Walker control file keywords
Contents
 List of all control file keywords

Detailed description of control file keywords
 Keyword 'C0'
 Keyword 'C3'
 Keyword 'C4'
 Keyword 'COM1'
 Keyword 'COM2'
 Keyword 'S'
 Keyword 'T'
 Keyword 'b'
 Keyword 'beta'
 Keyword 'betapdf'
 Keyword 'bprime'
 Keyword 'c'
 Keyword 'centering'
 Keyword 'cja'
 Keyword 'cja_accurate'
 Keyword 'coeff'
 Keyword 'const_coeff'
 Keyword 'const_shear'
 Keyword 'cov'
 Keyword 'decay'
 Keyword 'default'
 Keyword 'depvar'
 Keyword 'diag_ou'
 Keyword 'dirichlet'
 Keyword 'dirichletpdf'
 Keyword 'dissipation'
 Keyword 'dt'
 Keyword 'elem'
 Keyword 'end'
 Keyword 'eq_A005H'
 Keyword 'eq_A005L'
 Keyword 'eq_A005S'
 Keyword 'eq_A05H'
 Keyword 'eq_A05L'
 Keyword 'eq_A05S'
 Keyword 'eq_A075H'
 Keyword 'eq_A075L'
 Keyword 'eq_A075S'
 Keyword 'evolution'
 Keyword 'exodusii'
 Keyword 'filetype'
 Keyword 'fixed'
 Keyword 'fluctuation'
 Keyword 'format'
 Keyword 'fullvar'
 Keyword 'gamma'
 Keyword 'gamma_method'
 Keyword 'gammapdf'
 Keyword 'gaussian'
 Keyword 'gendir'
 Keyword 'glm'
 Keyword 'gmshbin'
 Keyword 'gmshtxt'
 Keyword 'gnorm'
 Keyword 'gnorm_accurate'
 Keyword 'gravity'
 Keyword 'heavy'
 Keyword 'homdecay'
 Keyword 'homogeneous'
 Keyword 'hydroproductions'
 Keyword 'hydrotimescale'
 Keyword 'hydrotimescales'
 Keyword 'icbeta'
 Keyword 'icdelta'
 Keyword 'icdirichlet'
 Keyword 'icgamma'
 Keyword 'icgaussian'
 Keyword 'icjointgaussian'
 Keyword 'init'
 Keyword 'inst_velocity'
 Keyword 'interval'
 Keyword 'jointbeta'
 Keyword 'jointcorrgaussian'
 Keyword 'jointdelta'
 Keyword 'jointdirichlet'
 Keyword 'jointgamma'
 Keyword 'jointgaussian'
 Keyword 'kappa'
 Keyword 'kappaprime'
 Keyword 'lambda'
 Keyword 'light'
 Keyword 'massfracbeta'
 Keyword 'mean'
 Keyword 'mean_gradient'
 Keyword 'mixdirichlet'
 Keyword 'mixmassfracbeta'
 Keyword 'mixnumfracbeta'
 Keyword 'montecarlo_homdecay'
 Keyword 'mu'
 Keyword 'multiple'
 Keyword 'ncomp'
 Keyword 'node'
 Keyword 'normalization'
 Keyword 'npar'
 Keyword 'nstep'
 Keyword 'numfracbeta'
 Keyword 'omega'
 Keyword 'ornsteinuhlenbeck'
 Keyword 'overwrite'
 Keyword 'pari'
 Keyword 'pdfs'
 Keyword 'policy'
 Keyword 'position'
 Keyword 'precision'
 Keyword 'prod_A005H'
 Keyword 'prod_A005L'
 Keyword 'prod_A005S'
 Keyword 'prod_A05H'
 Keyword 'prod_A05L'
 Keyword 'prod_A05S'
 Keyword 'prod_A075H'
 Keyword 'prod_A075L'
 Keyword 'prod_A075S'
 Keyword 'product'
 Keyword 'r'
 Keyword 'r123_philox'
 Keyword 'r123_threefry'
 Keyword 'raw'
 Keyword 'rcomma'
 Keyword 'rho'
 Keyword 'rho2'
 Keyword 'rng'
 Keyword 'rngs'
 Keyword 'rngsse_gm19'
 Keyword 'rngsse_gm29'
 Keyword 'rngsse_gm31'
 Keyword 'rngsse_gm55'
 Keyword 'rngsse_gm61'
 Keyword 'rngsse_gq58.1'
 Keyword 'rngsse_gq58.3'
 Keyword 'rngsse_gq58.4'
 Keyword 'rngsse_lfsr113'
 Keyword 'rngsse_mrg32k3a'
 Keyword 'rngsse_mt19937'
 Keyword 'scientific'
 Keyword 'seed'
 Keyword 'seqlen'
 Keyword 'sigmasq'
 Keyword 'skewnormal'
 Keyword 'slm'
 Keyword 'solve'
 Keyword 'spike'
 Keyword 'stationary'
 Keyword 'statistics'
 Keyword 'term'
 Keyword 'theta'
 Keyword 'title'
 Keyword 'ttyi'
 Keyword 'txt'
 Keyword 'variant'
 Keyword 'velocity'
 Keyword 'walker'
 Keyword 'wrightfisher'
 Keyword 'zero'
This page documents the control file keywords of Walker.
List of all control file keywords
C0 real Set Langevin SDE parameter C0 C3 real Set gamma (dissipation) SDE parameter C3 C4 real Set gamma (dissipation) SDE parameter C4 COM1 real Set gamma (dissipation) SDE parameter COM1 COM2 real Set gamma (dissipation) SDE parameter COM2 S real(s) Set SDE parameter(s) S T real(s) Set SDE parameter(s) T b real(s) Set SDE parameter(s) b beta Introduce the beta SDE input block betapdf 4 reals Configure a beta distribution bprime real(s) Set SDE parameter(s) bprime c real(s) Set SDE parameter(s) c centering string Specify datacentering for PDF output cja Select the Cheng, Johnk, Atkinson algorithm for sampling a beta cja_accurate Select the accurate Cheng, Johnk, Atkinson algorithm for sampling a beta coeff string Select the coefficients policy const_coeff Select constant coefficients policy const_shear Select constant shear coefficients policy cov real(s) Set SDE parameter(s) cov decay Select decay coefficients policy default Select the default ASCII floatingpoint output depvar character Select dependent variable (in a relevant block) diag_ou Introduce the diagonal OrnsteinUhlenbeck SDE input block dirichlet Start configuration block for the Dirichlet SDE dirichletpdf reals Configure a Dirichlet distribution dissipation Introduce the (particle) dissipation equation input block or coupling dt real Select constant time step size elem Specify elemcentering for output end End of an input block eq_A005H Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light<<heavy eq_A005L Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light>>heavy eq_A005S Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light=heavy eq_A05H Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light<<heavy eq_A05L Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light>>heavy eq_A05S Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light=heavy eq_A075H Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light<<heavy eq_A075L Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light>>heavy eq_A075S Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light=heavy evolution Select PDF output policy evolution exodusii Select ExodusII output filetype string Select output file type fixed Select the fixed ASCII floatingpoint output fluctuation string Select fluctuation (as the dependent variable) to solve for format string Specify the ASCII floatingpoint output format fullvar string Select full variable (as the dependent variable) to solve for gamma Introduce the gamma SDE input block gamma_method string Select an Intel MKL gamma RNG method gammapdf 2 reals Configure a gamma distribution gaussian 2 reals Configure a Gaussian distribution gendir Start configuration block for the generalized Dirichlet SDE glm string Select the generalized Langevin model for the velocity PDF model gmshbin Select Gmsh binary output for outputing PDFs gmshtxt Select Gmsh ASCII output for outputing PDFs gnorm Select the GNORM (see MKL doc) algorithm for sampling a gamma gnorm_accurate Select the accurate GNORM (see MKL doc) algorithm for sampling a gamma gravity 3 reals Set Langevin SDE parameter gravity heavy string Select the heavyfluid normalization for the mixture Dirichlet SDE homdecay Select homogeneous decay coefficients policy homogeneous Select homogeneous coefficients policy hydroproductions string(s) Set MixMassFractionBeta SDE parameter(s) productions hydrotimescale Select hydrotimescale coefficients policy hydrotimescales string(s) Set MixMassFractionBeta SDE parameter(s) hydrotimescales icbeta Introduce an icbeta...end block used to configure beta distributions icdelta Introduce a icdelta...end block used to configure delta spikes icdirichlet Configure a Dirichlet PDF as initial condition icgamma Configure a gamma distribution as initial condition icgaussian Configure a joint uncorrelated Gaussian as initial condition icjointgaussian Configure an joint correlated Gaussian as initial condition init string Select initialization policy inst_velocity Select the instantaneous velocity coefficients policy interval uint Set interval (within a relevant block) jointbeta Select the joint beta initialization policy jointcorrgaussian Select the joint correlated Gaussian initialization policy jointdelta Select the joint delta initialization policy jointdirichlet Select the Dirichlet initialization policy jointgamma Select the joint gamma initialization policy jointgaussian Select the joint Gaussian initialization policy kappa real(s) Set SDE parameter(s) kappa kappaprime real(s) Set SDE parameter(s) kappaprime lambda real(s) Set SDE parameter(s) lambda light string Select the lightfluid normalization for the mixture Dirichlet SDE massfracbeta Introduce the massfracbeta SDE input block mean real(s) Set SDE parameter(s) mean mean_gradient real(s) Set prescribed mean gradient mixdirichlet Start configuration block for the Mixture Dirichlet SDE mixmassfracbeta Introduce the mixmassfracbeta SDE input block mixnumfracbeta Introduce the mixnumfracbeta SDE input block montecarlo_homdecay Select Monte Carlo homogeneous decay coefficients policy mu real(s) Set SDE parameter(s) mu multiple Select PDF output policy multiple ncomp uint Set number of scalar components for a system of differential equations node Specify nodecentering for output normalization string Select mixture Dirichlet PDF model normalization type npar uint Set total number of particles nstep uint Set number of time steps to take numfracbeta Introduce the numfracbeta SDE input block omega real(s) Set SDE parameter(s) omega ornsteinuhlenbeck Introduce the OrnsteinUhlenbeck SDE input block overwrite Select PDF output policy overwrite pari uint Set particles output interval pdfs Start of probability density function (PDF) input block policy string Select PDF output file policy position Introduce the (particle) position equation input block or coupling precision int Precision in digits for ASCII floatingpoint output prod_A005H Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light<<heavy prod_A005L Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light>>heavy prod_A005S Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light=heavy prod_A05H Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light<<heavy prod_A05L Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light>>heavy prod_A05S Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light=heavy prod_A075H Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light<<heavy prod_A075L Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light>>heavy prod_A075S Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light=heavy product string Select product (as the dependent variable) to solve for r real(s) Set SDE parameter(s) r r123_philox Select Random123 Philox RNG r123_threefry Select Random123 ThreeFry RNG raw Select the raw initialization policy rcomma real(s) Set SDE parameter(s) rcomma rho real(s) Set SDE parameter(s) rho rho2 real(s) Set SDE parameter(s) rho2 rng string Select random number generator (RNG) from pool of enabled RNGs rngs Start of a random number generators description input block rngsse_gm19 Select RNGSSE GM19 RNG rngsse_gm29 Select RNGSSE GM29 RNG rngsse_gm31 Select RNGSSE GM31 RNG rngsse_gm55 Select RNGSSE GM55 RNG rngsse_gm61 Select RNGSSE GM61 RNG rngsse_gq58.1 Select RNGSSE GQ58.1 RNG rngsse_gq58.3 Select RNGSSE GQ58.3 RNG rngsse_gq58.4 Select RNGSSE GQ58.4 RNG rngsse_lfsr113 Select RNGSSE LFSR113 RNG rngsse_mrg32k3a Select RNGSSE MRG32K3A RNG rngsse_mt19937 Select RNGSSE MT19937 RNG scientific Select the scientific ASCII floatingpoint output seed uint Set random number generator seed seqlen string Specify the RNGSSE RNG sequence length sigmasq real(s) Set SDE parameter(s) sigmasq skewnormal Start configuration block for the Skewnormal SDE slm string Select the simplified Langevin model (SLM) for the velocity PDF model solve string Select dependent variable to solve for spike even reals Configure a delta spike stationary Select the stationary coefficients policy statistics Start of statistics input block term real Set maximum nondimensional time to simulate theta real(s) Set SDE parameter(s) theta title string Set analysis title ttyi uint Set screen output interval txt Select ASCII output for outputing PDFs variant string Select velocity PDF model variant velocity real(s) Specify velocity walker Start configuration block of the random walker wrightfisher Start configuration block for the WrightFisher SDE zero Select the zero initialization policy
Detailed description of control file keywords
Keyword 'C0'
Set Langevin SDE parameter C0
This keyword is used to specify a real number used to parameterize the Langevin model for the fluctuating velocity in homogeneous variabledensity turbulence. Example: "C0 2.1".
Expected type: real
Keyword 'C3'
Set gamma (dissipation) SDE parameter C3
This keyword is used to specify a real number used to parameterize the gamma distribution dissipation (turbulence frequency) model for particles Example: "C3 1.0".
Expected type: real
Lower bound: 0.000000
Keyword 'C4'
Set gamma (dissipation) SDE parameter C4
This keyword is used to specify a real number used to parameterize the gamma distribution dissipation (turbulence frequency) model for particles Example: "C4 0.25".
Expected type: real
Lower bound: 0.000000
Keyword 'COM1'
Set gamma (dissipation) SDE parameter COM1
This keyword is used to specify a real number used to parameterize the gamma distribution dissipation (turbulence frequency) model for particles Example: "COM1 0.44".
Expected type: real
Lower bound: 0.000000
Keyword 'COM2'
Set gamma (dissipation) SDE parameter COM2
This keyword is used to specify a real number used to parameterize the gamma distribution dissipation (turbulence frequency) model for particles Example: "COM2 0.9".
Expected type: real
Lower bound: 0.000000
Keyword 'S'
Set SDE parameter(s) S
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "S 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'T'
Set SDE parameter(s) T
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "T 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'b'
Set SDE parameter(s) b
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "b 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'beta'
Introduce the beta SDE input block
This keyword is used to introduce a beta ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), with linear drift and quadratic diagonal diffusion, whose invariant is the joint beta distribution. For more details on the beta SDE, see https:/
Keyword 'betapdf'
Configure a beta distribution
This keyword is used to specify the configuration of beta distributions for the beta initialization policy. The configuration is given by four real numbers inside a betapdf...end block. Example: "betapdf 0.2 0.3 0.0 1.0 end", which specifies a univariate beta distribution with shape parameters 0.2 and 0.3, displacement 0.0, and scale 1.0. See also the help on keyword icbeta.
Expected type: 4 reals
Keyword 'bprime'
Set SDE parameter(s) bprime
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "bprime 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'c'
Set SDE parameter(s) c
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "c 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'centering'
Specify datacentering for PDF output
This keyword is used to select the data centering of the probability value output on the sample space grid for file output of probability density functions (PDFs). Example: "centering elem", which selects elementcentered values. Valid options are 'elem' and 'node', denoting cellcentered and pointcentered output, respectively.
Expected type: string
Expected valid choices: 'elem'  'node'
Keyword 'cja'
Select the Cheng, Johnk, Atkinson algorithm for sampling a beta
This keyword is used to select the ChengJohnkAtkinson method used to generate beta random numbers using the Intel Math Kernel Library (MKL) random number generators.
Keyword 'cja_accurate'
Select the accurate Cheng, Johnk, Atkinson algorithm for sampling a beta
This keyword is used to select the accurate version of the ChengJohnkAtkinson method used to generate beta random numbers using the Intel Math Kernel Library (MKL) random number generators.
Keyword 'coeff'
Select the coefficients policy
This keyword is used to select a coefficients policy. This is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Expected type: string
Expected valid choices: 'const_coeff'  'decay'  'homogeneous'  'homdecay'  'montecarlo_homdecay'  'hydrotimescale'  'const_shear'  'stationary'  'inst_velocity'
Keyword 'const_coeff'
Select constant coefficients policy
This keyword is used to select the 'constant coefficients' coefficients policy. A coefficients policy is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const_coeff", which selects 'constant coefficients' coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'const_shear'
Select constant shear coefficients policy
This keyword is used to select the prescribed constant shear coefficients policy, used to compute a homogeneous free shear flow using the Langevin model. This policy (or model) prescribes a constant mean shear in the y direction and computes the dissipation of turbulent kinetic energy specifically for this flow. The flow is a fully developed homogeneous turbulent shear flow with a uniform mean velocity gradient in one direction (y) and the mean flow is in predominantly in the x direction. The flow is considered to be far from solid boundaries. See Pope, S.B. (2000). Turbulent flows (Cambridge: Cambridge University Press).
Keyword 'cov'
Set SDE parameter(s) cov
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "cov 4.0 2.5 1.1 32.0 5.6 23.0 end" The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'decay'
Select decay coefficients policy
This keyword is used to select the decay coefficients policy. This policy (or model) is used to constrain a beta stochastic differential equation so that its variance, <y^2>, always decays. A coefficients policy, in general, is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'default'
Select the default ASCII floatingpoint output
This keyword is used to select the 'default' floatingpoint output format for ASCII floatingpoint real number output. Example: "format default", which selects the default floatingpoint output. Valid options are 'default', 'fixed', and 'scientific'. For more info on these various formats, see http:/
Keyword 'depvar'
Select dependent variable (in a relevant block)
Dependent variable, e.g, in differential equations.
Expected type: character
Keyword 'diag_ou'
Introduce the diagonal OrnsteinUhlenbeck SDE input block
This keyword is used to introduce a diag_ou ... end block, where 'diag_ou' stands for diagonal OrnsteinUhlenbeck' and is used to specify the configuration of a system of stochastic differential equations (SDEs), with linear drift and constant diagonal diffusion, whose invariant is the joint normal distribution. Keywords allowed in a diagou ... end block: 'depvar', 'ncomp', 'rng', 'init', 'coeff', 'sigmasq', 'theta', 'mu'. For an example diagou ... end block, see doc/html/walker_example_diagou.html.
Keyword 'dirichlet'
Start configuration block for the Dirichlet SDE
This keyword is used to introduce a dirichlet ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), whose invariant is the Dirichlet distribution. For more details on the Dirichlet SDE, see https:/
Keyword 'dirichletpdf'
Configure a Dirichlet distribution
This keyword is used to specify the configuration of a Dirichlet distribution for the Dirichlet initialization policy. The configuration is given by a vector of positive real numbers inside a dirichletpdf...end block. Example: "dirichletpdf 0.1 0.3 0.2 end"  prescribe a Dirichlet distribution with shape parameters 0.1, 0.3, and 0.2. See also the help on keyword icdirichlet.
Expected type: reals
Keyword 'dissipation'
Introduce the (particle) dissipation equation input block or coupling
This keyword is used to introduce a dissipation ... end block, used to specify the configuration of a system of deterministic or stochastic differential equations, governing a particle quantity that models the dissipation rate of turbulent kinetic energy, used to coupled to particle velocity model, e.g, the Langevin, model. Note that the random number generator r123_philox is automatically put on the list as a selected RNG if no RNG is selected. Keywords allowed in a dissipation ... end block: 'depvar', 'rng', 'init', 'coeff', 'velocity', 'For an example dissipation ... end block, see doc/html/walker_example_dissipation.html. (2) To specify a dependent variable (by a character) used to couple a differential equation system, in which the 'dissipation' keyword appears) to another labeled by a 'depvar'.
Keyword 'dt'
Select constant time step size
This keyword is used to specify the time step size that used as a constant during simulation. Setting 'cfl' and 'dt' are mutually exclusive. If both 'cfl' and 'dt' are set, 'dt' wins.
Expected type: real
Lower bound: 0.000000
Keyword 'elem'
Specify elemcentering for output
This keyword is used to select elemcentering for variable output. In walker for example, this is used to configure probability values on the sample space grid for file output of probability density functions (PDFs). Example: "centering elem", which selects elementcentered values. Valid options are 'elem' and 'node', denoting cellcentered and pointcentered output, respectively. In inciter this keyword is used in output variable specification blocks, prefixing variable names by either 'node' or 'elem', to specify their centering for output to file.
Keyword 'end'
End of an input block
The end of a block is given by the 'end' keyword in the input file. Example: "rngs ... end".
Keyword 'eq_A005H'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light<<heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.05, IC: light << heavy.
Keyword 'eq_A005L'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light>>heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.05, IC: light >> heavy.
Keyword 'eq_A005S'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.05, IC:light=heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.05, IC: light = heavy.
Keyword 'eq_A05H'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light<<heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.5, IC: light << heavy.
Keyword 'eq_A05L'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light>>heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.5, IC: light >> heavy.
Keyword 'eq_A05S'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.5, IC:light=heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.5, IC: light = heavy.
Keyword 'eq_A075H'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light<<heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.75, IC: light << heavy.
Keyword 'eq_A075L'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light>>heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.75, IC: light >> heavy.
Keyword 'eq_A075S'
Select inverse equilibrium hydro time scale from DNS of HRT, A=0.75, IC:light=heavy
Inverse equilibrium hydrodynamics time scale from DNS of homogeneous RayleighTaylor instability, tau_eq, A = 0.75, IC: light = heavy.
Keyword 'evolution'
Select PDF output policy evolution
This keyword is used to select the 'evolution' output file policy for requested probability density functions (PDFs) within a pdfs ... end block. Example: "policy evolution", which selects the evolution output file policy. The evolution policy output appends new time step to the same output file for each time instant, yielding a time evolution of data in a single file. Valid PDF policy options are 'overwrite', 'multiple', and 'evolution'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'exodusii'
Select ExodusII output
This keyword is used to select the ExodusII output file type readable by, e.g., ParaView of either a requested probability density function (PDF) within a pdfs ... end block or for meshbased field output in a field_output ... end block. Example: "filetype exodusii", which selects ExodusII file output. For more info on ExodusII, see http:/
Keyword 'filetype'
Select output file type
This keyword is used to specify the output file type of a requested probability density function (PDF) within a pdfs ... end block or for meshbased field output in a field_output ... end block. Example: "filetype exodusii", which selects ExodusII output. Valid options depend on which block the keyword is used: in a pdfs ... end the valid choices are 'txt', 'gmshtxt', 'gmshbin', and 'exodusii', in a field_output ... end block the valid choices are 'exodusii' and 'root'.
Expected type: string
Expected valid choices: 'txt'  'gmshtxt'  'gmshbin'  'root'  'exodusii'
Keyword 'fixed'
Select the fixed ASCII floatingpoint output
This keyword is used to select the 'fixed' floatingpoint output format for ASCII floatingpoint real number output. Example: "format fixed", which selects the fixed floatingpoint output. Valid options are 'default', 'fixed', and 'scientific'. For more info on these various formats, see http:/
Keyword 'fluctuation'
Select fluctuation (as the dependent variable) to solve for
This keyword is used to select the fluctuation of a random variable as what quantity to solve for, i.e., use as the dependent variable, e.g., in a position or velocity model for a stochastic particle. This configures how statistics must be interpreted.
Expected type: string
Keyword 'format'
Specify the ASCII floatingpoint output format
This keyword is used to select the floatingpoint output format for ASCII floatingpoint number output. Example: "format scientific", which selects the scientific floatingpoint output. Valid options are 'default', 'fixed', and 'scientific'. For more info on these various formats, see http:/
Expected type: string
Expected valid choices: 'default'  'scientific'  'fixed'
Keyword 'fullvar'
Select full variable (as the dependent variable) to solve for
This keyword is used to select the full random (instantaneous) variable as what quantity to solve for, i.e., use as the dependent variable, in, e.g., a position or velocity model for a stochastic particle. This configures how statistics must be interpreted.
Expected type: string
Keyword 'gamma'
Introduce the gamma SDE input block
This keyword is used to introduce the gamma ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), with linear drift and linear diagonal diffusion, whose invariant is the joint gamma distribution.
Keyword 'gamma_method'
Select an Intel MKL gamma RNG method
This keyword is used to specify the method used to generate gamma random numbers using the Intel Math Kernel Library (MKL) random number generators. Valid options are 'gnorm' and 'gnorm_accurate'.
Expected type: string
Expected valid choices: 'gnorm'  'gnorm_accurate'
Keyword 'gammapdf'
Configure a gamma distribution
This keyword is used to specify the configuration of gamma distributions for the gamma initialization policy. The configuration is given by two real numbers inside a gammapdf...end block. Example: "gammapdf 0.2 0.3 end", which specifies a univariate gamma distribution with shape and scale parameters 0.2 and 0.3, respectively. See also the help on keyword icgamma.
Expected type: 2 reals
Keyword 'gaussian'
Configure a Gaussian distribution
This keyword is used to specify the configuration of Gaussian distributions for the jointgaussian initialization policy. The configuration is given by two real numbers inside a gaussian...end block. Example: "gaussian 0.2 0.3 end", which specifies a Gaussian distribution with 0.2 mean and 0.3 variance. See also the help on keyword icgaussian.
Expected type: 2 reals
Keyword 'gendir'
Start configuration block for the generalized Dirichlet SDE
This keyword is used to introduce a gendir ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), whose invariant is Lochner's generalized Dirichlet distribution. For more details on the generalized Dirichlet SDE, see https:/
Keyword 'glm'
Select the generalized Langevin model for the velocity PDF model
This keyword is used to select the generalized Langevin model for the Lagrangian velocity in turbulent flows.
Expected type: string
Keyword 'gmshbin'
Select Gmsh binary output for outputing PDFs
This keyword is used to select the binary output file type readable by Gmsh of a requested probability density function (PDF) within a pdfs ... end block. Example: "filetype gmshbin", which selects Gmsh binary file output. Valid options are 'txt', 'gmshtxt', 'gmshbin', and 'exodusii'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'gmshtxt'
Select Gmsh ASCII output for outputing PDFs
This keyword is used to select the ASCII (text) output file type readable by Gmsh of a requested probability density function (PDF) within a pdfs ... end block. Example: "filetype gmshtxt", which selects Gmsh ASCII file output. Valid options are 'txt', 'gmshtxt', 'gmshbin', and 'exodusii'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'gnorm'
Select the GNORM (see MKL doc) algorithm for sampling a gamma
This keyword is used to select the GNORM method used to generate gamma random numbers using the Intel Math Kernel Library (MKL) random number generators.
Keyword 'gnorm_accurate'
Select the accurate GNORM (see MKL doc) algorithm for sampling a gamma
This keyword is used to select the accurate version of the GNORM method used to generate gamma random numbers using the Intel Math Kernel Library (MKL) random number generator.
Keyword 'gravity'
Set Langevin SDE parameter gravity
This keyword is used to specify a vector of 3 real numbers used to parameterize the Langevin model for the fluctuating velocity in homogeneous variabledensity turbulence, prescribing a gravy body force in the three coordinate directions, x, y, z. Example: "gravity 0.0 0.2 1.0 end".
Expected type: 3 reals
Keyword 'heavy'
Select the heavyfluid normalization for the mixture Dirichlet SDE
This keyword is used to select the heavyfluid normalization for the mixture Dirichlet PDF/SDE model for multimaterial mixing in turbulent flows.
Expected type: string
Keyword 'homdecay'
Select homogeneous decay coefficients policy
This keyword is used to select the homogeneous decay coefficients policy. This policy (or model) is used to constrain a beta stochastic differential equation so that its variance, <y^2>, always decays and its mean, <R> = rho2/(1+r<RY>/<R>), where Y = <Y> + y, does not change in time. Note that R = rho2/(1+rY). This policy is similar to 'montecarlo_homdecay', but computes the SDE coefficient S in a different but statistically equivalent way. While 'homdecay' only requires the estimation of statistics, <R>, <r^2>, and <r^3>, 'montecarlo_homdecay' requires <R^2>, <YR^2>, and <Y(1Y)R^3>. A coefficients policy, in general, is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'homogeneous'
Select homogeneous coefficients policy
This keyword is used to select the homogeneous coefficients policy. This policy (or model) is used to constrain a Dirichlet stochastic differential equation so that its mean density stays constant. A coefficients policy, in general, is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'hydroproductions'
Set MixMassFractionBeta SDE parameter(s) productions
This keyword is used to specify a vector of strings used to parameterize the system of stochastic differential equations, configured in a mixmassfracbeta ... end block. Within the mixmassfracbeta ... end block the coefficients policy must be set to 'hydrotimescale' in order for the hydroproductions ... end block to be in effect. The 'hydroproductions' keyword is then used to specify a list of strings, each specifying which turbulent kinetic energy production dividied by the dissipation rate (P/eps) data (from direct numerical simulations) should be used for the particular component integrated. Available P/eps data are defined in src/
Expected type: string(s)
Keyword 'hydrotimescale'
Select hydrotimescale coefficients policy
This keyword is used to select the hydrodynamicstimescale coefficients policy. This policy (or model) is used to constrain a beta stochastic differential equation (SDE) so that its variance, <y^2>, always decays and its mean, <R> = rho2/(1+r<RY>/<R>), where Y = <Y> + y, does not change in time. Note that R = rho2/(1+rY). This policy is similar to 'homdecay' as well as 'montecarlo_homdecay', but instead of simply constraining b' and kappa' to ensure decay in the evolution of <y^2>, b' and kappa' are specified as functions of an externallyspecified hydrodynamics time scale, as a function of time. This policy is more similar to 'homdecay' than to 'montecarlo_homdecay' in that only requires the estimation of statistics, <R>, <r^2>, and <r^3>. A coefficients policy, in general, is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'hydrotimescales'
Set MixMassFractionBeta SDE parameter(s) hydrotimescales
This keyword is used to specify a vector of strings used to parameterize the system of stochastic differential equations, configured in a mixmassfracbeta ... end block. Within the mixmassfracbeta ... end block the coefficients policy must be set to 'hydrotimescale' in order for the hydrotimescales ... end block to be in effect. The 'hydrotimescales' keyword is then used to specify a list of strings, each specifying which inverse time scale should be used for the particular component integrated. Available time scales are defined in src/DiffEq/HydroTimescales.hpp. Example: "hydrotimescales eq_A05S
eq_A05H eq_A05L eq_A05S eq_A05S end", which configures five inverse hydrodynamics time scales associated to 5 components, i.e., 5 scalar stochastic differential equations, integrated, specified and configured within the given mixmassfracbeta ... end block. The length of the hydrotimescales vector depends on the number of scalar components and is controlled by the preceding keyword 'ncomp'. For mixmassfracbeta, ncomp is the actual number of scalar components * 4, since mixmassfractionbeta always computes 4 additional derived stochastic variables (in a diagnostic) fashion. See also MixMassFractionBeta::derived() in src/
Expected type: string(s)
Keyword 'icbeta'
Introduce an icbeta...end block used to configure beta distributions
This keyword is used to introduce an icbeta...end block in which beta distributions are configured for the beta initialization policy. Example: "init jointbeta"  select beta initpolicy,"icbeta betapdf 0.2 0.3 0.0 1.0 end end"  prescribe a univariate beta distribution with shape parameters 0.2 and 0.3, displacement 0.0, and scale 1.0. See also the help on keyword jointbeta and betapdf.
Keyword 'icdelta'
Introduce a icdelta...end block used to configure delta spikes
This keyword is used to introduce a icdelta...end block in which delta spikes are configured for the delta initialization policy. Example: "init jointdelta"  select joint delta initpolicy,"icdelta spike 0.1 0.3 0.9 0.7 end end"  prescribe a univariate distribution that consists of two deltaspikes at sample space positions 0.1 and 0.9 with spike heights 0.3 and 0.7, respectively. Note that the sum of the heights must add up to unity. See also the help on keyword jointdelta and spike.
Keyword 'icdirichlet'
Configure a Dirichlet PDF as initial condition
This keyword is used to introduce an icdirichlet...end block in which a Dirichlet distribution is configured for the Dirichlet initialization policy
Keyword 'icgamma'
Configure a gamma distribution as initial condition
This keyword is used to introduce an icgamma...end block in which gamma distributions are configured for the gamma initialization policy. Example: "init jointgamma"  select gamma initpolicy,"icgamma gammapdf 0.2 0.3 end end"  prescribe a univariate gamma distribution with shape and scale parameters 0.2 and 0.3, respectively. See also the help on keyword jointgamma and gammapdf.
Keyword 'icgaussian'
Configure a joint uncorrelated Gaussian as initial condition
This keyword is used to introduce an icgaussian...end block in which Gaussian distributions are configured for the jointgaussian initialization policy. Example: "init jointgaussian"  select jointgaussian initpolicy,"icgaussian gaussian 0.2 0.3 end end"  prescribes a univariate Gaussian distribution with 0.2 mean and 0.3 variance. See also the help on keyword jointgaussian and gaussian.
Keyword 'icjointgaussian'
Configure an joint correlated Gaussian as initial condition
This keyword is used to introduce an icjointgaussian...end block in which a multivariate joint Gaussian distribution is configured for the jointgaussian initialization policy. Example: "init jointgaussian"  select jointgaussian initpolicy, " icjointgaussian mean 0.0 0.5 1.0 end cov 4.0 2.5 1.1 32.0 5.6 23.0 end end"  prescribes a trivariate joint Gaussian distribution with means 0.0, 0.5 and 1.0, and a covariance matrix which must be symmetric positive definite. See also the help on keyword jointgaussian and gaussian.
Keyword 'init'
Select initialization policy
This keyword is used to select an initialization policy. This is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init raw", which selects raw initialization policy, which leaves the memory uninitialized. Note that this option may behave differently depending on the particular equation or physical model. See the init policies in DiffEq/
Expected type: string
Expected valid choices: 'raw'  'zero'  'jointdelta'  'jointbeta'  'jointgaussian'  'jointcorrgaussian'  'jointgamma'
Keyword 'inst_velocity'
Select the instantaneous velocity coefficients policy
This keyword is used to select the instantaneous velocity coefficients policy. This is used to prescribe a coupling for instantaneous velocity to some other differential equation, e.g., to update Lagrangian particle position or to couple a mix model to velocity.
Keyword 'interval'
Set interval (within a relevant block)
This keyword is used to specify an interval in time steps. This must be used within a relevant block.
Expected type: uint
Lower bound: 0
Keyword 'jointbeta'
Select the joint beta initialization policy
This keyword is used to select the joint beta initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'jointcorrgaussian'
Select the joint correlated Gaussian initialization policy
This keyword is used to select the joint correlated Gaussian initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'jointdelta'
Select the joint delta initialization policy
This keyword is used to select the joint delta initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'jointdirichlet'
Select the Dirichlet initialization policy
This keyword is used to select the Dirichlet initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'jointgamma'
Select the joint gamma initialization policy
This keyword is used to select the joint gamma initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'jointgaussian'
Select the joint Gaussian initialization policy
This keyword is used to select the joint Gaussian initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. For an example, see tk::InitPolicies in DiffEq/
Keyword 'kappa'
Set SDE parameter(s) kappa
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "kappa 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'kappaprime'
Set SDE parameter(s) kappaprime
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "kappaprime 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'lambda'
Set SDE parameter(s) lambda
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "lambda 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'light'
Select the lightfluid normalization for the mixture Dirichlet SDE
This keyword is used to select the lightfluid normalization for the mixture Dirichlet PDF/SDE model for multimaterial mixing in turbulent flows.
Expected type: string
Keyword 'massfracbeta'
Introduce the massfracbeta SDE input block
This keyword is used to introduce a massfracbeta ... end block, used to specify the configuration of a system of numberfraction beta SDEs, a system of stochastic differential equations (SDEs), in which, in addition to the dependent variable, computed with linear drift and quadratic diagonal diffusion (whose invariant is joint beta), two additional variables are computed. In other words, this is a beta SDE but there are two additional stochastic variables computed based on the beta SDE. If Y is governed by the beta SDE, then the massfraction beta SDE additionally governs rho(Y) and V(Y), where both rho and V are random variables, computed by rho(Y) = rho2 / ( 1 + r Y ), and V(Y) = ( 1 + r Y ) / rho2. For more details on the beta SDE, see https:/
Keyword 'mean'
Set SDE parameter(s) mean
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "mean 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'mean_gradient'
Set prescribed mean gradient
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "mean_gradient 1.0 1.0 0.0 end". One use of a mean gradient vector is to specify a prescribed mean scalar gradient in 3 spatial directions for a scalar transprot equation.
Expected type: real(s)
Keyword 'mixdirichlet'
Start configuration block for the Mixture Dirichlet SDE
This keyword is used to introduce a mixdirichlet ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), whose invariant is the Dirichlet distribution constrained to model multimaterial mixing in turbulent flows. For more details on the Dirichlet SDE, see https:/
Keyword 'mixmassfracbeta'
Introduce the mixmassfracbeta SDE input block
This keyword is used in multiple ways: (1) To introduce a mixmassfracbeta ... end block, used to specify the configuration of a system of mix massfraction beta SDEs, a system of stochastic differential equations (SDEs), whose solution is the joint beta distribution and in which the usual beta SDE parameters b and kappa are specified via functions that constrain the beta SDE to be consistent with the turbulent mixing process. The mix massfraction beta SDE is similar to the massfraction beta SDE, only the process is made consistent with the nomix and fully mixed limits via the specification of the SDE coefficients b and kappa. As in the massfraction beta SDE, Y is governed by the beta SDE and two additional stochastic variables are computed. However, in the mix massfraction beta SDE the parameters b and kappa are given by b = Theta * b' and kappa = kappa' * <y^2>, where Theta = 1
 <y^2> / [ <Y> ( 1  <Y> ], the fluctuation about the mean, <Y>, is defined as usual: y = Y  <Y>, and b' and kappa' are userspecified constants. Similar to the massfraction beta SDE, there two additional random variables computed besides, Y, and they are rho(Y) and V(Y). For more detail on the massfraction beta SDE, see the help on keyword 'massfracbeta'. For more details on the beta SDE, see https:/
/ and src/doi.org/ 10.1080/ 14685248.2010.510843 DiffEq/ . Keywords allowed in a mixmassfracbeta ... end block: 'depvar', 'ncomp', 'rng', 'init', 'coeff', 'bprime', 'S', 'kappaprime', 'rho2', 'hydrotimescales', 'hydroproductions', 'velocity', 'dissipation', 'r'. For an example mixmassfracbeta ... end block, see doc/html/walker_example_mixmassfracbeta.html. (2) To specify a dependent variable (by a character) used to couple a differential equation system, in which the 'mixmassfracbeta' keyword appears) to another labeled by a 'depvar'.Beta/ Beta.hpp
Keyword 'mixnumfracbeta'
Introduce the mixnumfracbeta SDE input block
This keyword is used to introduce a mixnumfracbeta ... end block, used to specify the configuration of a system of mix numberfraction beta SDEs, a system of stochastic differential equations (SDEs), whose solution is the joint beta distribution and in which the usual beta SDE parameters b and kappa are specified via functions that constrain the beta SDE to be consistent with the turbulent mixing process. The mix numberfraction beta SDE is similar to the numberfraction beta SDE, only the process is made consistent with the nomix and fully mixed limits via the specification of the SDE coefficients b and kappa. As in the numberfraction beta SDE, X is governed by the beta SDE and two additional stochastic variables are computed. However, in the mix numberfraction beta SDE the parameters b and kappa are given by b = Theta * b' and kappa = kappa' * <x^2>, where Theta = 1
 <x^2> / [ <X> ( 1  <X> ], the fluctuation about the mean, <X>, is defined as usual: x = X  <X>, and b' and kappa' are userspecified constants. Similar to the numberfraction beta SDE, there two additional random variables computed besides, X, and they are rho(X) and V(X). For more detail on the numberfraction beta SDE, see the help on keyword 'numfracbeta'. For more details on the beta SDE, see https:/
/ and src/DiffEq/Beta/Beta.h. Keywords allowed in a mixnumfracbeta ... end block: 'depvar', 'ncomp', 'rng', 'init', 'coeff', 'bprime', 'S', 'kappaprime', 'rho2', 'rcomma'. For an example mixnumfracbeta ... end block, see doc/html/walker_example_mixnumfracbeta.html.doi.org/ 10.1080/ 14685248.2010.510843
Keyword 'montecarlo_homdecay'
Select Monte Carlo homogeneous decay coefficients policy
This keyword is used to select the Monte Carlo homogeneous decay coefficients policy. This policy (or model) is used to constrain a beta stochastic differential equation (SDE) so that its variance, <y^2>, always decays and its mean, <R> = rho2/(1+r<RY>/<R>), where Y = <Y> + y, does not change in time. Note that R = rho2/(1+rY). This policy is similar to 'homdecay', but computes the the SDE coefficient S in a different but statistically equivalent way. While 'homdecay' only requires the estimation of statistics, <R>, <r^2>, and <r^3>, 'montecarlo_homdecay' requires <R^2>, <YR^2>, and <Y(1Y)R^3>. A coefficients policy, in general, is used to specify how the coefficients are set at each time step during timeintegration. Example: "coeff const", which selects constant coefficients policy, which sets constant coefficients before t = 0 and leaves the coefficients unchanged during time integration. Note that this option may behave differently depending on the particular equation or physical model.
Keyword 'mu'
Set SDE parameter(s) mu
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "mu 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'multiple'
Select PDF output policy multiple
This keyword is used to select the 'multiple' output file policy for requested probability density functions (PDFs) within a pdfs ... end block. Example: "policy multiple", which selects the multiple output file policy. The multiple policy output creates a new file for each time step. Valid PDF policy options are 'overwrite', 'multiple', and 'evolution'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'ncomp'
Set number of scalar components for a system of differential equations
This keyword is used to specify the number of scalar components of a vector. 'ncomp' means "number of components". It is also used for specifying the number of scalar components of a transporter scalar (see also the keywords 'transport').
Expected type: uint
Lower bound: 1
Keyword 'node'
Specify nodecentering for output
This keyword is used to select nodecentering for variable output. In walker for example, this is used to configure probability values on the sample space grid for file output of probability density functions (PDFs). Example: "centering elem", which selects elementcentered values. Valid options are 'elem' and 'node', denoting cellcentered and pointcentered output, respectively. In inciter this keyword is used in output variable specification blocks, prefixing variable names by either 'node' or 'elem', to specify their centering for output to file.
Keyword 'normalization'
Select mixture Dirichlet PDF model normalization type
This keyword is used to select the mixture Dirichlet PDF model normalization type.
Expected type: string
Expected valid choices: 'light'  'heavy'
Keyword 'npar'
Set total number of particles
This keyword is used to specify the total number of particles in a simulation.
Expected type: uint
Lower bound: 1
Keyword 'nstep'
Set number of time steps to take
This keyword is used to specify the number of time steps to take in a simulation. The number of time steps are used in conjunction with the maximmum time specified by keyword 'term': the simulation stops whichever is reached first. Both 'nstep' and 'term' can be left unspecified, in which case their default values are used. See also 'term'.
Expected type: uint
Lower bound: 1
Keyword 'numfracbeta'
Introduce the numfracbeta SDE input block
This keyword is used to introduce a numfracbeta ... end block, used to specify the configuration of a system of numberfraction beta SDEs, a system of stochastic differential equations (SDEs), in which, in addition to the dependent variable, computed with linear drift and quadratic diagonal diffusion (whose invariant is joint beta), two additional variables are computed. In other words, this is a beta SDE but there are two additional stochastic variables computed based on the beta SDE. If X is governed by the beta SDE, then the numberfraction beta SDE additionally governs rho(X) and V(X), where both rho and V are random variables, computed by rho(X) = rho2 ( 1  r' X ), and V(X) = 1 / [ rho2 ( 1  r'X ) ]. For more details on the beta SDE, see https:/
Keyword 'omega'
Set SDE parameter(s) omega
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "omega 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'ornsteinuhlenbeck'
Introduce the OrnsteinUhlenbeck SDE input block
This keyword is used to introduce an ornsteinuhlenbeck ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), with linear drift and constant diffusion, whose invariant is the joint normal distribution. Keywords allowed in an ornsteinuhlenbeck ... end block: 'depvar', 'ncomp', 'rng', 'init', 'coeff', 'sigmasq', 'theta', 'mu'. For an example ornsteinuhlenbeck ... end block, see doc/html/walker_example_ou.html.
Keyword 'overwrite'
Select PDF output policy overwrite
This keyword is used to select the the 'overwrite' output file policy for requested probability density functions (PDFs) within a pdfs ... end block. Example: "policy overwrite", which selects the overwrite output file policy. The overwrite policy overwrites the same output file containing a single time step. Valid PDF policy options are 'overwrite', 'multiple', and 'evolution'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'pari'
Set particles output interval
This keyword is used to specify the interval in time steps for particles output during a simulation.
Expected type: uint
Lower bound: 1
Keyword 'pdfs'
Start of probability density function (PDF) input block
This keyword is used to start a block in the input file containing the descriptions and settings of requested output for probability density functions (PDFs). Example: "pdfs mypdf( y1 : 1.0e2 ) end", which requests a singlevariate PDF to be output to file, whose sample space variable is y1, using automatic determination of the bounds of the sample space, using 1.0e2 as the sample space bin size, and call the PDF "mypdf". For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'policy'
Select PDF output file policy
This keyword is used to select the output file policy for requested probability density functions (PDFs) within a pdfs ... end block. Example: "policy overwrite", which selects the overwrite output file policy. Valid options are 'overwrite', 'multiple', and 'evolution'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Expected type: string
Expected valid choices: 'overwrite'  'multiple'  'evolution'
Keyword 'position'
Introduce the (particle) position equation input block or coupling
This keyword is used to introduce a position ... end block, used to specify the configuration of a system of deterministic or stochastic differential equations, governing particle positions usually in conjunction with velocity model, e.g, the Langevin, model. Note that the random number generator r123_philox is automatically put on the list as a selected RNG if no RNG is selected. Keywords allowed in a position ... end block: 'depvar', 'rng', 'init', 'coeff', 'velocity', 'For an example position ... end block, see doc/html/walker_example_position.html. (2) To specify a dependent variable (by a character) used to couple a differential equation system, in which the 'position' keyword appears) to another labeled by a 'depvar'.
Keyword 'precision'
Precision in digits for ASCII floatingpoint output
This keyword is used to select the precision in digits for ASCII floatingpoint real number output. Example: "precision 10", which selects ten digits for floatingpoint output, e.g., 3.141592654. The number of digits must be larger than zero and lower than the maximum representable digits for the given floatingpoint type, defined by std::numeric_limits< FLOAT_TYPE >::digits10+2. For more info on setting the precision in C++, see http:/
Expected type: int
Lower bound: 1
Upper bound: 16
Expected valid choices: integer between [1...16] (both inclusive)
Keyword 'prod_A005H'
Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light<<heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.05, IC: light << heavy.
Keyword 'prod_A005L'
Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light>>heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.05, IC: light >> heavy.
Keyword 'prod_A005S'
Select production divided by dissipation rate from DNS of HRT, A=0.05, IC:light=heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.05, IC: light = heavy.
Keyword 'prod_A05H'
Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light<<heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.5, IC: light << heavy.
Keyword 'prod_A05L'
Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light>>heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.5, IC: light >> heavy.
Keyword 'prod_A05S'
Select production divided by dissipation rate from DNS of HRT, A=0.5, IC:light=heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.5, IC: light = heavy.
Keyword 'prod_A075H'
Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light<<heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.75, IC: light << heavy.
Keyword 'prod_A075L'
Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light>>heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.75, IC: light >> heavy.
Keyword 'prod_A075S'
Select production divided by dissipation rate from DNS of HRT, A=0.75, IC:light=heavy
Production divided by dissipation rate from DNS of homogeneous RayleighTaylor instability, P/e, A = 0.75, IC: light = heavy.
Keyword 'product'
Select product (as the dependent variable) to solve for
This keyword is used to select the product of multiple random variables as what quantity to solve for, i.e., use as the dependent variable, e.g., in a velocity model, solve for the product of the full density and the full velocity, i.e., the full momentum, for a stochastic particle. This configures how statistics must be interpreted.
Expected type: string
Keyword 'r'
Set SDE parameter(s) r
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "r 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'r123_philox'
Select Random123 Philox RNG
This keyword is used to select the Philox generator, based on Feistel network and integer multiplication, provided by the Random123 random number generator library. For more info on Random123 see http:/
Keyword 'r123_threefry'
Select Random123 ThreeFry RNG
This keyword is used to select the ThreeFry generator, related to the Threefish block cipher from Skein Hash Function, provided by the Random123 random number generator library. For more info on Random123 see http:/
Keyword 'raw'
Select the raw initialization policy
This keyword is used to select the raw initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init raw", which selects raw initialization policy, which leaves the memory uninitialized. Note that this option may behave differently depending on the particular equation or physical model. See the the init policies in DiffEq/
Keyword 'rcomma'
Set SDE parameter(s) rcomma
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "rcomma 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'rho'
Set SDE parameter(s) rho
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "rho 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'rho2'
Set SDE parameter(s) rho2
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "rho2 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'rng'
Select random number generator (RNG) from pool of enabled RNGs
This keyword is used to select a particular random number generator (RNG) from a preselected set of (enabled and configured) pool of RNGs. The pool is specified by the 'rngs ... end' block and it must precede the selection of an RNG.
Expected type: string
Expected valid choices: 'r123_threefry'  'r123_philox'  'rngsse_gm19'  'rngsse_gm29'  'rngsse_gm31'  'rngsse_gm55'  'rngsse_gm61'  'rngsse_gq58.1'  'rngsse_gq58.3'  'rngsse_gq58.4'  'rngsse_mt19937'  'rngsse_lfsr113'  'rngsse_mrg32k3a' Remember: the RNG must be listed in the pool before it can be selected via this keyword!
Keyword 'rngs'
Start of a random number generators description input block
This keyword is used to start a block in the input file containing the descriptions and settings of requested random number generators. Example: "rngs mkl_mcg59 seed 2134 uniform_method accurate end end" which enables the MCG59 generator from MKL using the seed 2134. For more info on the structure of the rngs ... end block, see doc/pages/rngs_
Keyword 'rngsse_gm19'
Select RNGSSE GM19 RNG
This keyword is used to select the GM19 random number generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gm29'
Select RNGSSE GM29 RNG
This keyword is used to select the GM29 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gm31'
Select RNGSSE GM31 RNG
This keyword is used to select the GM31 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gm55'
Select RNGSSE GM55 RNG
This keyword is used to select the GM55 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gm61'
Select RNGSSE GM61 RNG
This keyword is used to select the GM61 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gq58.1'
Select RNGSSE GQ58.1 RNG
This keyword is used to select the GQ58.1 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gq58.3'
Select RNGSSE GQ58.3 RNG
This keyword is used to select the GQ58.3 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSS2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_gq58.4'
Select RNGSSE GQ58.4 RNG
This keyword is used to select the GQ58.4 generator, using a method based on parallel evolution of an ensemble of transformations of a twodimensional torus, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_lfsr113'
Select RNGSSE LFSR113 RNG
This keyword is used to select the LFSR113 generator, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_mrg32k3a'
Select RNGSSE MRG32K3A RNG
This keyword is used to select the MRG32K3A generator, a combined multiple recursive random number generator with two components of order 3, provided by the RNGSS2 random number generator library. For more info on RNGSSE see https:/
Keyword 'rngsse_mt19937'
Select RNGSSE MT19937 RNG
This keyword is used to select the MT19937 generator, a Mersenne Twister generator, provided by the RNGSSE2 random number generator library. For more info on RNGSSE see https:/
Keyword 'scientific'
Select the scientific ASCII floatingpoint output
This keyword is used to select the 'scientific' floatingpoint output format for ASCII floatingpoint real number output. Example: "format scientific", which selects the scientific floatingpoint output. Valid options are 'default', 'fixed', and 'scientific'. For more info on these various formats, see http:/
Keyword 'seed'
Set random number generator seed
This keyword is used to specify a seed for a random number generator Example: rngmkl_mcg31 seed 1234 end
Expected type: uint
Keyword 'seqlen'
Specify the RNGSSE RNG sequence length
This keyword is used to select a random number generator sequence length, used by the RNGSSE2 random number generator library. Valid options are 'short', 'medium', and 'long'. For more info on RNGSSE see https:/
Expected type: string
Expected valid choices: 'short'  'medium'  'long'
Keyword 'sigmasq'
Set SDE parameter(s) sigmasq
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "sigmasq 4.0 2.5 1.1 32.0 5.6 23.0 end" The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'skewnormal'
Start configuration block for the Skewnormal SDE
This keyword is used to introduce a skewnormal ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), whose invariant is the joint skewnormal distribution. For more details on the skewnormal distribution, see http:/
Keyword 'slm'
Select the simplified Langevin model (SLM) for the velocity PDF model
This keyword is used to select the simplified Langevin model (SLM) for the Lagrangian velocity in turbulent flows.
Expected type: string
Keyword 'solve'
Select dependent variable to solve for
This keyword is used to select an the quantity (the dependent variable) to solve for in walker's position and/or velocity model. This configures how statistics must be interpreted.
Expected type: string
Expected valid choices: 'fullvar'  'fluctuation'  'product'  'fluctuating_momentum'
Keyword 'spike'
Configure a delta spike
This keyword is used to specify the configuration of delta spikes for, the delta initialization policy. The configuration is given by an even set of real numbers inside a spike...end block. Example: "spike 0.1 1.0 end", which specifies a delta spike at sample space position 0.1 with relative height 1.0. The height must be between [0.0...1.0] inclusive and specifies a relative probability. See also the help on keyword icdelta.
Expected type: even reals
Keyword 'stationary'
Select the stationary coefficients policy
This keyword is used to select the stationary coefficients policy. This policy will keep a stochastic differential equation at a constant statistically stationary state.
Keyword 'statistics'
Start of statistics input block
This keyword is used to start a block in the input file containing the descriptions and settings of requested output for statistical moments. Example: "statistics <Y> <yy> end", which requests the first two moments of the flutcutating variable 'Y'. For more info on the structure of the statistics ... end block, see doc/pages/statistics_
Keyword 'term'
Set maximum nondimensional time to simulate
This keyword is used to specify the termination time in a simulation. The termination time and number of time steps, specified by 'nstep', are used in conjunction to determine when to stop a simulation: whichever is reached first. Both 'nstep' and 'term' can be left unspecified, in which case their default values are used. See also 'nstep'.
Expected type: real
Lower bound: 0.000000
Keyword 'theta'
Set SDE parameter(s) theta
This keyword is used to specify a vector of real numbers used to parameterize a system of stochastic differential equations. Example: "theta 5.0 2.0 3.0 end". The length of the vector depends on the particular type of SDE system and is controlled by the preceding keyword 'ncomp'.
Expected type: real(s)
Keyword 'title'
Set analysis title
The analysis title may be specified in the input file using the 'title' keyword. The 'title' keyword must be followed by a doublequoted string specifying the analysis title. Example: title "Example problem". Specifying a title is optional.
Expected type: string
Keyword 'ttyi'
Set screen output interval
This keyword is used to specify the interval in time steps for screen output during a simulation.
Expected type: uint
Lower bound: 0
Keyword 'txt'
Select ASCII output for outputing PDFs
This keyword is used to select the text output file type of a requested probability density function (PDF) within a pdfs ... end block. Example: "filetype txt", which selects textfile output. Valid options are 'txt', 'gmshtxt', 'gmshbin', and 'exodusii'. For more info on the structure of the pdfs ... end block, see doc/pages/statistics_
Keyword 'variant'
Select velocity PDF model variant
This keyword is used to select the velocity PDF model variant.
Expected type: string
Expected valid choices: 'slm'  'glm'
Keyword 'velocity'
Specify velocity
This keyword is used to configure a velocity vector, used for, e.g., boundary or initial conditions.
Expected type: real(s)
Keyword 'walker'
Start configuration block of the random walker
This keyword is used to select the walker. Walker, is a random walker, that allows temporal integration of a system of ordinary or stochastic differential equations (SDEs) of various types and the collection of arbitrary coupled statistics and probability density functions. Walker is intended as a general mathematical tool to analyze the behavior of SDEs and its statistics.
Keyword 'wrightfisher'
Start configuration block for the WrightFisher SDE
This keyword is used to introduce a wright_fisher ... end block, used to specify the configuration of a system of stochastic differential equations (SDEs), whose invariant is the Dirichlet distribution. For more details on the WrightFisher SDE, see http:/
Keyword 'zero'
Select the zero initialization policy
This keyword is used to select the zero initialization policy. The initialization policy is used to specify how the initial conditions are set at t = 0 before timeintegration. Example: "init zero", which selects zero initialization policy, which puts zeros in memory. Note that this option may behave differently depending on the particular equation or physical model. See the init policies in DiffEq/