project2linspace -- project a rational point onto affine subspace

Usage:

xp = project2linspace(A,b,x0)
Inputs:
- A, a matrix,
- b, a matrix, a vector
- x0, a matrix, a rational vector
Outputs:
- xp, a matrix, the projection of x0

Description

Projects a rational point $x_0$ onto the affine subspace given by $A x = b$

The source of this document is in SemidefiniteProgramming/SDPdoc.m2:373:0.