tic ; F = F + w ; x = F\b ; toc
tic ; y = (A+w*w')\b ;      toc
norm (x-y)

tic ; F = F - t ; x = F\b ; toc
tic ; y = (A+w*w'-t*t')\b ; toc
norm (x-y)
</pre><pre class="codeoutput">Elapsed time is 0.032744 seconds.
Elapsed time is 0.198138 seconds.
ans =
   3.3726e-17
Elapsed time is 0.035119 seconds.
Elapsed time is 0.207019 seconds.
ans =
   3.4408e-17
</pre><h2>Caveat Executor<a name="19"></a></h2>
         <p>One caveat:  If you have a large number of very small systems to solve, the object-oriented ove