/**
* ExpVector substitution. Clone and set exponent to d at position i.
*
* @param i position.
* @param d new exponent.
* @return substituted ExpVector.
*/
public ExpVector subst(int i, long d) {
ExpVector V = (ExpVector) this.clone();
long e = V.setVal(i, d);
return V;
// return EVSU(this, i, d);
}
