XSLPchgvar

Purpose

This subroutine is deprecated and will be removed in a future release.
Define a column as an SLP variable or change the characteristics and values of an existing SLP variable.

Topic area

Data Input

Synopsis

int XPRS_CC XSLPchgvar(XSLPprob prob, int col, int *detrow, double *initstepbound, double *stepbound, double *penalty, double *damp, double *initial, double *value, int *tolset, int *history, int *converged, int *vartype);

Arguments

prob

The current SLP problem.

col

The index of the matrix column.

detrow

Address of an integer holding the index of the determining row. Use -1 if there is no determining row. May be NULL if not required.

initstepbound

Address of a double precision variable holding the initial step bound size. May be NULL if not required.

stepbound

Address of a double precision variable holding the current step bound size. Use zero to disable the step bounds. May be NULL if not required.

penalty

Address of a double precision variable holding the weighting of the penalty cost for exceeding the step bounds. May be NULL if not required.

damp

Address of a double precision variable holding the damping factor for the variable. May be NULL if not required.

initial

Address of a double precision variable holding the initial value for the variable. May be NULL if not required.

value

Address of a double precision variable holding the current value for the variable. May be NULL if not required.

tolset

Address of an integer holding the index of the tolerance set for this variable. Use zero if there is no specific tolerance set. May be NULL if not required.

history

Address of an integer holding the history value for this variable. May be NULL if not required.

converged

Address of an integer holding the convergence status for this variable. May be NULL if not required.

vartype

Address of an integer holding a bitmap defining the existence of certain properties for this variable:

Bit 1:	Variable has a delta vector
Bit 2:	Variable has an initial value
Bit 14:	Variable is the reserved "=" column

May be NULL if not required.

Example

The following example sets an initial value of 1,42 and tolerance set 2 for column 25 in the matrix.

double InitialValue;
int vartype, tolset;

InitialValue = 1,42;
tolset = 2;
vartype = 1<<1 | 1<<2;

XSLPchgvar(prob, 25, NULL, NULL, NULL, NULL,
   NULL, &InitialValue, NULL, &tolset,
   NULL, NULL, &vartype);

Note that bits 1 and 2 of vartype are set, indicating that the variable has a delta vector and an initial value. For columns already defined as SLP variables, use XSLPgetvar to obtain the current value of vartype because other bits may already have been set by the system.

Further information

1. If any of the arguments is NULL then the corresponding information for the variable will be left unaltered. If the information is new (i.e. the column was not previously defined as an SLP variable) then the default values will be used.

2. Changing history or converged is only effective during SLP iterations, changing value only during iterations and before calling functions that specifically use this like XSLPcascade.

3. Changing initial and initstepbound is only effective before XSLPconstruct.

4. If a value of XPRS_PLUSINFINITY is used in the value for stepbound or initstepbound, the delta will never have step bounds applied, and will almost always be regarded as converged.

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XSLPchgvar