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CPXchgcoef

int CPXPUBLIC CPXchgcoef(CPXCENVptr env, CPXLPptr lp, int i, int j, double newvalue)
Definition file: cplex.h
Include files: cplex.h

The routine CPXchgcoef is used to change a single coefficient in the constraint matrix, linear objective coefficients, right-hand side or ranges of a CPLEX problem object. The coefficient is specified using its coordinates in the constraint matrix. When changing matrix coefficients from zero to nonzero values, be sure that the corresponding row and column indices exist in the problem, so that -1 ≤ i < CPXgetnumrows(env,lp) and -2 ≤ j < CPXgetnumcols(env,lp)

Example

 status = CPXchgcoef (env, lp, 10, 15, 23.2);

See Also:

CPXchgobj, CPXchgrhs, CPXchgrngval

Parameters:

env

A pointer to the CPLEX environment as returned by CPXopenCPLEX.

lp

A pointer to a CPLEX problem object as returned by CPXcreateprob.

i

An integer that indicates the numeric index of the row in which the coefficient is located. The linear objective row is referenced with i = -1.

j

An integer that indicates the numeric index of the column in which the coefficient is located. The RHS column is referenced with j = -1. The range value column is referenced with j = -2. If j = -2 is specified and row i is not a ranged row, an error status is returned.

newvalue

The new value for the coefficient being changed.

Returns:

The routine returns zero on success and nonzero if an error occurs.