Documentation


GRBaddgenconstrOr

int GRBaddgenconstrOr ( GRBmodel *model,
    const char *name,
    int resvar,
    int nvars,
    int* vars )

Add a new general constraint of type GRB_GENCONSTR_OR 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).

An OR constraint <span>$</span>r = \mbox{or}\{x_1,\ldots,x_n\}<span>$</span> states that the binary resultant variable <span>$</span>r<span>$</span> should be <span>$</span>1<span>$</span> if and only if any of the operand variables <span>$</span>x_1,\ldots,x_n<span>$</span> is equal to <span>$</span>1<span>$</span>. If all operand variables are <span>$</span>0<span>$</span>, then the resultant should be <span>$</span>0<span>$</span> as well.

Note that all variables participating in such a constraint will be forced to be binary; independently of how they were created.

Arguments:

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.

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

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

const int *vars: An array containing the indices of the binary operand variables <span>$</span>x_j<span>$</span> over which the OR concatenation will be taken.

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 = or(x1, x3, x4) */
  int ind[] = {1, 3, 4};
  error = GRBaddgenconstrOr(model, "orconstr", 5, 3, ind);