petsc-3.13.6 2020-09-29
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Gets the scalar value for a particular option in the database. Logically Collective on the communicator passed in PetscOptionsBegin()


#include "petscsys.h"
PetscErrorCode PetscOptionsScalar(PetscOptionItems *PetscOptionsObject,const char opt[],const char text[],const char man[],PetscScalar currentvalue,PetscScalar *value,PetscBool  *set)

Input Parameters

opt - option name
text - short string that describes the option
man - manual page with additional information on option
currentvalue - the current value; caller is responsible for setting this value correctly. Normally this is done with either
                PetscOptionsScalar(..., obj->value,&obj->value,...) or
                value = defaultvalue
                PetscOptionsScalar(..., value,&value,&flg);
                if (flg) {

Output Parameter

value - the value to return
flg - PETSC_TRUE if found, else PETSC_FALSE


If the user does not supply the option at all value is NOT changed. Thus you should ALWAYS initialize value if you access it without first checking if the set flag is true.

The default/currentvalue passed into this routine does not get transferred to the output value variable automatically.

Must be between a PetscOptionsBegin() and a PetscOptionsEnd()

See Also

PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(), PetscOptionsGetInt(),
PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool() PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(), PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(), PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(), PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(), PetscOptionsFList(), PetscOptionsEList()







Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages