To check whether the problem was solved to optimality.
sym_isOptimal()
This post-solution query routine is used to learn whether the problem was solved to
optimality.
It prints whether or not the problem was solved to optimality to scilab console.
This function takes no arguments
It returns 1 if the problem was solved to optimality or 0 if it was not solved to optimality or -1 if there was an error.