Initial Guess

Initial Guess = {char_string} [filename]

Description / Usage

This optional card directs the initialization of the entire unknown vector. Three options are provided to set the entire solution field to numerical values determined by {char_string}. Three additional options are available for reading initial values of the solution vector from data files. The permissible values of {char_string} are:

zero

For an initial guess of zero (0.) for each degree of freedom in the unknown vector.

one

For an initial guess of one (1.) for each degree of freedom in the unknown vector.

random

For a random initial guess (between 0. and 1.) for each degree of freedom in the unknown vector.

read

To obtain the initial guess by reading the ASCII data file identified as the GUESS file, which must have initially been a SOLN file or a tmp_i.d (Write Intermediate Results) file.

read_exoII

To obtain the initial guess from the EXODUS II file specified by the FEM file card that is also used to supply mesh data. Any extraneous variables in the EXODUS II file that are not in the list of active variables for the current problem description are simply ignored.

read_exoII_file file name

To read the initial guess for the field variables from an EXODUS II database file different from the initial mesh database file. The file_name is specified as a single string following the read_exoII_file keyword. As with the read_exoII option, any extraneous variables not specified as active variables for the simulation will be simply ignored.

If this card is omitted, then the default behavior is to assume that a value of zero has been specified for {char_string}.

Examples

Following is a sample card:

Initial Guess = zero

Initial Guess = read_exoII_file      First_Iteration.exoII

Technical Discussion

This card provides the specification of the initial vector of unknowns in a problem. In most cases this vector is specified to be identically zero, though in some cases a nonzero vector may be of value (see Technical Discussion section of Debug card). The first three options (zero, one, random) employ an internally-generated vector of initial values, while the read option utilizes the values read from an ASCII solution file (see SOLN input card) previously calculated by Goma, and the read_exoII options employ solutions read from binary (exoII) files, not necessarily always generated by Goma.