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enQuote:mecej4 wrote:
https://software.intel.com/en-us/comment/1747740#comment-1747740
<a id="comment-1747740"></a>
<div class="field field-name-comment-body field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p><strong class="quote-header">Quote:</strong><blockquote class="quote-msg quote-nest-1 odd"><div class="quote-author"><em class="placeholder">mecej4</em> wrote:</div></p>
<p>With a condition number of 4E15, and the 15.95 decimal digits that 64-bit reals provide, you have <strong>less than one</strong> reliable digit in your solution. How, then, do you conclude that "the result of the first equation is correct"?</p>
<p>To proceed further, we need to know more data on a case where you judge the results to be wrong -- for example, you may provide a file containing the Pardiso solutions and another containing the "correct" solutions from another (please specify its identity completely).</p>
<p></blockquote></p>
<p>I have compared the solution with other two solvers, the origional sequential solver that use ILU precondition and PETSc. The latter two solver can generate close results while Pardiso cannot. More important, this is from a flow problem, we check the results with theoretical analysis and we are sure the results by the other two solvers are correct, at least, resonable.</p>
<p>One question is that Pardiso can solve one equation correctly, seems that for matrices with high condition number, Pardiso may solve it by chance.</p>
<p>Please find the results compare in the attached file (some of them have also been included in the previous attachment), where x_pardiso_i.txt is the result of pardiso, x_PETSc_i.txt is the result of PETSc and x_i.txt is the result of origional sequential solver, i is the ith linear equation.</p>
<p>Thanks,</p>
<p>Daniel</p>
</div></div></div>Sat, 17 Aug 2013 17:54:37 +0000danielsuecomment 1747740 at https://software.intel.comWith a condition number of
https://software.intel.com/en-us/comment/1747724#comment-1747724
<a id="comment-1747724"></a>
<div class="field field-name-comment-body field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>With a condition number of 4E15, and the 15.95 decimal digits that 64-bit reals provide, you have <strong>less than one</strong> reliable digit in your solution. How, then, do you conclude that "the result of the first equation is correct"?</p>
<p>To proceed further, we need to know more data on a case where you judge the results to be wrong -- for example, you may provide a file containing the Pardiso solutions and another containing the "correct" solutions from another solver (please specify its identity completely).</p>
</div></div></div>Sat, 17 Aug 2013 09:15:00 +0000mecej4comment 1747724 at https://software.intel.com