:  3704 time:   0.0052 resid: 9.058758e-11
</pre><h2>LU and LINSOLVE are fast and accurate but complicated to use<a name="8"></a></h2>
         <p>A quick look at ``help lu'' will scroll off your screen.  For full matrices, [L,U,p] = lu (A,'vector') is fastest.  Then for
            the forward/backsolves, use LINSOLVE instead of BACKSLASH for even faster performance.  But for sparse matrices, use the optional
            'Q' output of LU so you get a good fill-reducing ordering.  But you can't use 'Q' if t