code: public SDVariable replaceWhere(SDVariable update, SDVariable from, Condition condition) {
          return replaceWhere(null, update, from, condition);
      }
docs: Element-wise replace where condition:<br>
  out[i] = from[i] if condition(update[i]) is satisfied, or<br>
  out[i] = update[i] if condition(update[i]) is NOT satisfied
  
  @param update    Source array
  @param from      Replacement values array (used conditionally). Must be same shape as 'update' array
  @param condition Condition to check on update array elements
  @return New array with values replaced where condition is satisfied