How to use

expressionValue

method

in

jscl.math.function.Sgn

public Generic selfExpand() {
  final Generic result = selfEvaluate();
  if (result == null) {
    return expressionValue();
  } else {
    return result;
  }
}

public Generic selfSimplify() {
  final Generic result = selfEvaluate();
  if (result == null) {
    try {
      Variable v = parameters[0].variableValue();
      if (v instanceof Abs) {
        return JsclInteger.valueOf(1);
      } else if (v instanceof Sgn) {
        Function f = (Function) v;
        return f.selfSimplify();
      }
    } catch (NotVariableException e) {
    }
    return expressionValue();
  } else {
    return result;
  }
}