🚀 go-pugleaf

I have a Least Square Estimation problem which took me a long time but
still couldn't figure out the the method to solve it. I'm sure that 
there is no expilict solution, what I want to know  is the computer
searching algorithm. Could somebody help me?

The problem is to minimize the next function:

       \sum_{s} ||b_{s} - A_{s} *B *c_{s} ||^{2}

where	b_{s}: vector of T by 1,(T is very large, could be thousands), known
	A_{s}: Matrix of T by m, known
	B:     Matrix of m by n,(m > n, m:n could be 100:5), unkown.
	c_{s}: vector of n by 1, unknown.

	\sum_{s} means sum over s, s is the foot note.

Any helpful suggestion is appreciated.