Quote:
Originally Posted by Xing Wu
Hello, I have a question about linear regression,
Ax=b, how to find constrained solution, like some elements of x have to be positive.
Thank you.

One possibility is to minimize Ax  b subject to the constraints of nonnegative x, which is a linear programming problem. If you want to minimize the squared error subject to nonnegative x, it would be a quadratic programming problem. Hope this helps.