How to Multiply cv::Mat with mask

I'd like multiply two arrays(cv::Mat) with mask for speed up application. In add and subtraction exists **mask** - optional operation mask - 8-bit single channel array, that specifies elements of the output array to be changed Provide OpenCV similar functionality for multiplication and divide? I can fill multiplier by mask with neutral element(1). But this is slow down. I can multiply with operation per pixel(two cycles through columns and rows), but in this case I need to know data type(uchar, double, int, ...) for template function Mat::at