public SDVariable subi(SDVariable sameDiffVariable) {
        return subi(sameDiff.generateNewVarName(new SubOp().opName(),0),sameDiffVariable);

    }
public SDVariable subi ( SDVariable sameDiffVariable ) { return subi ( sameDiff . generateNewVarName ( new SubOp ( ) . opName ( ) , 0 ) , sameDiffVariable ) ; }
@param sameDiffVariable
@return