<div dir="ltr"><div dir="ltr">On Wed, Jan 15, 2020 at 9:59 AM Xiangdong <<a href="mailto:epscodes@gmail.com">epscodes@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Maybe I am not clear. I want to solve the block tridiagonal system Tx=b a few times with same T but different b. On CPU, I can have it by applying the ILU0 and reuse the factorization. Since it is block tridiagonal, ILU0 would give same results as LU.<div><br></div><div>I am trying to do the same thing on GPU with chowiluviennacl, but found default factorization does not produce the exact factorization for tridiagonal system. Can we tight the drop off tolerance so that it can work as LU for tridiagonal system?</div></div></blockquote><div><br></div><div>There are no options in our implementation. You could look at the ViennaCL manual to see if we missed something.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Thank you.</div><div><br></div><div>Xiangdong<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jan 15, 2020 at 9:41 AM Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">On Wed, Jan 15, 2020 at 9:36 AM Xiangdong <<a href="mailto:epscodes@gmail.com" target="_blank">epscodes@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Can chowiluviennacl do ilu0? <div><br></div><div>I need to solve a tri-diagonal system directly. If I apply the PCILU, I will obtain the exact solution with preonly + pcilu. However, the preonly + chowiluviennacl will not provide the exact solution. Any option keys to set the CHOWILUVIENNACL filling level or dropping off tolerance like the standard ilu?</div></div></blockquote><div><br></div><div>No. However, such a scheme makes less sense here. This algorithm spawns a individual threads for individual elements. Drop tolerance</div><div>is not less work, it is sparser, but that should not matter for a tridiagonal system. Levels also is not applicable since you have only 1 level.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Thank you.</div><div><br></div><div>Best,</div><div>Xiangdong</div><div><br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jan 14, 2020 at 10:05 PM Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">On Tue, Jan 14, 2020 at 9:56 PM Xiangdong <<a href="mailto:epscodes@gmail.com" target="_blank">epscodes@gmail.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Dear Developers,</div><div><br></div><div>I have a quick question about the chowiluviennacl. When I tried to use it, I found that it only works for np=1, not np>1. However, in the description of chowiluviennacl.cxx, it says "the ViennaCL Chow-Patel parallel ILU preconditioner".</div></div></blockquote><div><br></div><div>By parallel, this means shared memory parallelism on the GPU.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>I am wondering whether I am using it correctly. Does chowiluviennacl work for np>1? </div></div></blockquote><div><br></div><div>I do not believe so. I do not see why it could not be extended, but that would mean writing some more code.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>In addition, are there option keys for the chowiluviennacl one can try?</div><div>Thank you.</div><div><br></div><div>Best,</div><div>Xiangdong</div></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>
</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>
</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br></div></div></div></div></div></div></div></div>