XSLPgetdf
XSLPgetdf |
Purpose
Get a distribution factor
Synopsis
int XSLP_CC XSLPgetdf(XSLPprob Prob, int ColIndex, int RowIndex, double *Value)
Arguments
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Prob
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The current SLP problem.
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ColIndex
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The index of the column whose distribution factor is to be retrieved.
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RowIndex
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The index of the row from which the distribution factor is to be taken.
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Value
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Address of a double precision variable to receive the value of the distribution factor. May be
NULL if not required.
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Example
The following example retrieves the value of the distribution factor for column 282 in row 134 and changes it to be twice as large.
double Value; XSLPgetdf(prob,282,134,&Value); Value = Value * 2; XSLPchgdf(prob,282,134,&Value);
Further information
The distribution factor of a column in a row is the matrix coefficient of the corresponding delta vector in the row. Distribution factors are used in conventional recursion models, and are essentially normalized first-order derivatives. Xpress-SLP can accept distribution factors instead of initial values, provided that the values of the variables involved can all be calculated after optimization using determining rows, or by a callback.
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