Description
The routine CPXchgcoef() is used to change a single coefficient in the constraint matrix, objective coefficients, right-hand side or ranges of a LP 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)Synopsis
int CPXchgcoef (CPXENVptr env,
CPXLPptr lp,
int i,
int j,
double newvalue);
CPXENVptr envThe pointer to the CPLEX environment as returned by one of the
CPXopenCPLEX routines.
CPXLPptr lpA pointer to a CPLEX LP problem object as returned by
CPXcreateprob().
int iAn integer that indicates the numerical index of the row in which the coefficient is located. The objective row is referenced with
i = -1.
int jAn integer that indicates the numerical 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.
double newvalueThe new value for the coefficient being changed.
status = CPXchgcoef (env, lp, 10, 15, 23.2);