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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'>I’ve faced similar issues with std::complex, but the material below,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'>which is not in the C++ standard, has suppressed my fears. Not<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'>eliminated though.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'><a href="http://fftw.org/doc/Complex-numbers.html">http://fftw.org/doc/Complex-numbers.html</a> (has a broken link, corrected below)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1388.pdf">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1388.pdf</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'>Chetan<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> petsc-users-bounces@mcs.anl.gov [mailto:petsc-users-bounces@mcs.anl.gov] <b>On Behalf Of </b>Jack Poulson<br><b>Sent:</b> Tuesday, February 07, 2012 10:10 AM<br><b>To:</b> PETSc users list<br><b>Subject:</b> Re: [petsc-users] one compilation error in PETSc-dev with enabling GPU and complex number<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>On Tue, Feb 7, 2012 at 11:29 AM, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:<o:p></o:p></p><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><p class=MsoNormal>On Tue, Feb 7, 2012 at 11:20 AM, recrusader <<a href="mailto:recrusader@gmail.com" target="_blank">recrusader@gmail.com</a>> wrote:<o:p></o:p></p></div><div><div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><p class=MsoNormal>Whether is it possible to find an efficient mechanism to do the conversion between std::complex and cusp::complex when the conversion is necessary.<o:p></o:p></p></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal>That does not matter. This is a compile error. We are not going to change this right now, and it seems like you are not going<o:p></o:p></p></div><div><p class=MsoNormal>make the necessary changes, so I would say that complex numbers are not supported with our GPU code right now. The<o:p></o:p></p></div><div><p class=MsoNormal>change would involve using cusp::complex for PetscScalar, and I am not sure how much work that would entail.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal> Matt<o:p></o:p></p></div></div></blockquote><div><p class=MsoNormal><br>Matt, <o:p></o:p></p></div><div><p class=MsoNormal><br>You might be interested to hear that the C++03 standard states that "The effect of instantiating the template complex for any type other than float, double or long double is unspecified". Thus, complex quad precision with it is probably a bad idea and, if I'm not mistaken, the standard does not state that the class must store data in the form<br><br>double real, imag;<br><br>so this could potentially break interfaces (e.g., to BLAS or LAPACK). Maybe it would be worthwhile to avoid usage of std::complex and simultaneously fix the compatibility issue with cusp::complex. I recently ripped std::complex out of Elemental for the above reasons.<br><br>Jack<o:p></o:p></p></div></div></div></div></body></html>