Interesting, because http://www.cplusplus.com/reference/std/complex/complex/, which I recognize is not the C++ standard, just says that std::complex is specialized for those types, not restricted to them. Clang was happy to compile std::complex<int> and related for me just now, so we might want to worry about users doing this since we all know MPI users don't read the MPI standard so why should we expect MPI-C++ users to read both the MPI and C++ standards? JeffS was not necessarily suggesting we replace the C++ standard with a human being. He was suggesting someone write the proposal for this feature. I don't see how a standards document is going to produce draft text for the MPI standard. Do you? :-) Jeff On Tue, Jun 26, 2012 at 10:05 AM, Jed Brown <[email protected]> wrote:

On Tue, Jun 26, 2012 at 6:33 AM, Jeff Hammond <[email protected]> wrote:

...

So one issue to consider here is that std::complex is a template, not a single type. �One can presumably stick lots of types inside the brackets.

Good thing the C++ standards committee nipped that one in the bud:

26.4 The effect of instantiating the template complex for any type other than float, double, or long double�is unspecified. The specializations complex<float>, complex<double>, and complex<long double> are�literal types (3.9).

...

So the MPI Forum needs to figure out which of the existing C99 types that will work with this. �Do we support std::complex<long double>? How about std::complex<uint64_t>?

No

...

My reference is http://www.cplusplus.com/reference/std/complex/complex/, btw.

As a standards guy, why not use a standard (or a final draft, which you can have for free)?

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf

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-- Jeff Hammond Argonne Leadership Computing Facility University of Chicago Computation Institute [email protected] / (630) 252-5381 http://www.linkedin.com/in/jeffhammond https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond