<div class="gmail_quote">On Thu, Nov 4, 2010 at 10:18, Benjamin Sanderse <span dir="ltr"><<a href="mailto:B.Sanderse@cwi.nl">B.Sanderse@cwi.nl</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div id=":5z">I am not sure if I understand you correctly. During initialization, several matrices are formed by kronecker products, and the resulting matrices have the size of the number of unknowns; i.e. if n is the number of unknowns then the matrices are n x n, although they typically have only a*n nonzero elements, with a around 10-20.<br>
</div></blockquote><div><br></div><div>I'm curious about the structure of these kronecker products. For example, you may have</div><div><br></div><div>K = A \otimes B</div><div><br></div><div>Is either one of A or B dense? Are they both large and distributed, or is one much smaller than the other? If they are both distributed, what distribution do you want the vector to have?</div>
<div><br></div><div>A different question is, what problem are you solving? E.g. if this is a Galerkin method for stochastic PDE, it gives us some idea about the structure, and the natural follow-up question is what is the size of the (reduced how?) stochastic space, and do the stochastic basis functions have local or global support.</div>
<div> </div><div>Jed</div></div>