int GRBaddgenconstrNorm ( GRBmodel *model,
    const char *name,
    int resvar,
    int nvars,
    const int *vars,
    double which )

Add a new general constraint of type GRB_GENCONSTR_NORM to a model. Note that, due to our lazy update approach, the new constraint won't actually be added until you update the model (using GRBupdatemodel), optimize the model (using GRBoptimize), or write the model to disk (using GRBwrite).

A NORM constraint <span>$</span>r = \mbox{norm}\{x_1,\ldots,x_n\}<span>$</span> states that the resultant variable <span>$</span>r<span>$</span> should be equal to the vector norm of the argument vector <span>$</span>x_1,\ldots,x_n<span>$</span>.


model: The model to which the new general constraint should be added.

name: Name for the new general constraint. This argument can be NULL, in which case the constraint is given a default name.

resvar: The index of the resultant variable <span>$</span>r<span>$</span> whose value will be equal to the NORM of the other variables.

nvars: The number <span>$</span>n<span>$</span> of operand variables over which the NORM will be taken.

vars: An array containing the indices of the operand variables <span>$</span>x_j<span>$</span> over which the NORM will be taken. Note that this array may not contain duplicates.

which: Which norm to use. Options are 0, 1, 2, and GRB_INFINITY.

Return value:

A non-zero return value indicates that a problem occurred while adding the general constraint. Refer to the Error Code table for a list of possible return values. Details on the error can be obtained by calling GRBgeterrormsg.

Example usage:

  /* x5 = 2-norm(x1, x3, x4) */
  int ind[] = {1, 3, 4};
  error = GRBaddgenconstrNorm(model, "orconstr", 5, 3, ind, 2.0);