) computes the factorization of A and returns it as an
% object that you can reuse to solve a linear system with x=F\b.  It picks
% LU, QR, or Cholesky for you, just like BACKSLASH.
%
% S = inverse(A) is simpler yet.  It does NOT compute inv(A), but
% factorizes A.  When multiplying S*b, it doesn't mulitply by the inverse,
% but uses the correct forward/backsolve equations to solve the linear
% system.

n = 1000 ;
A = rand (n) ;
b = rand (n,1) ;
c = rand (n,1) ;

tic ;                       x = A\b ; y = A\