A\B is not faster when A is square and triangular
Reported by Sergei
BUG DESCRIPTION:
----------------
This code works slower (about three times)
N=5000;
Ncond=10;
S=rand(N,N);
B=rand(N,Ncond);
[L, U] = lu(S);
sol = U\(L\B);
than this one
sol=S\B;
check the conditioner number for this solution, it was not more than 10 ^ 7
time measurements have shown that most of the time is spent on code: sol = U \ (L \ B);