title: Solving system using linalg with constraints
body: <p>I want to solve some system in the form of matrices using <code>linalg</code>, but the resulting solutions should sum up to 1. For example, suppose there are 3 unknowns, x, y, z. After solving the system their values should sum up to 1, like .3, .5, .2. Can anyone please tell me how I can do that? </p>
  
  <p>Currently, I am using something like <code>result = linalg.solve(A, B)</code>, where <code>A</code> and <code>B</code> are matrices. But this doesn't return solutions in the range <code>[0, 1]</code>.</p>