r large matrices and sparse
% matrices.  Here's an illustration of how pathetic inv(A)*b can be.

A = gallery ('frank',16) ; xtrue = ones (16,1) ; b = A*xtrue ;

x = inv(A)*b ; norm (b-A*x)
x = A\b      ; norm (b-A*x)

%%
% The performance difference between BACKSLASH and INV for even small
% sparse matrices is striking.

load west0479 ;
A = west0479 ;
n = size (A,1)
b = rand (n,1) ;
tic ; x = A\b ; toc
norm (b-A*x)
tic ; x = inv(A)*b ; toc
norm (b-A*x)

%%
% What if you want to solve multiple systems?  Use