 from the M-files in the FACTORIZE package).
%
% Hopefully the object-oriented overhead will drop in future versions of
% MATLAB, and you can ignore this caveat.

A = rand (10) ; b = rand (10,1) ; F = factorize (A) ;

tic ; for k = 1:10000, x = F\b ; end ; toc

tic ; for k = 1:10000, x = A\b ; end ; toc

[L,U,p] = lu (A, 'vector') ;
opL = struct ('LT', true) ;
opU = struct ('UT', true) ;
tic ; 
for k = 1:10000
    x = linsolve (U, linsolve (L, b(p,:), opL), opU) ;
end
toc

%% Summary
%
% So ... don't use IN