boostorg/math

Complex number functions

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evanmiller commented

Are these still needed?

https://www.boost.org/doc/libs/1_81_0/libs/math/doc/html/inverse_complex.html

I see that all six of these functions are in std::complex as of C++11.

mborland commented

Since we are moving to C++14 in the next release we could add the [[deprecated("Replaced by C++11")]] attribute to these.

jzmaddock commented

I'm cool with that.

NAThompson commented

Are we sure that 1) these don't work with multiprecision, and 2) they aren't used by some standard library implementation?

mborland commented

Are we sure that 1) these don't work with multiprecision, and 2) they aren't used by some standard library implementation?

  1. They return std::complex which is limited to float, double, and long double

  2. That would be a question for @CaseyCarter or @StephanTLavavej. Does MSVC use Boost.Math for complex special functions? I know you use some of the others.

ckormanyos commented

work with multiprecision

When I was recently writing my new cpp_double_fp_backend for Multiprecision, I got the impression that these functions were used in some of the tests. I'm not sure if they are actually needed for the Multiprecision-backend implementations themselves.

I'll try to take a look before the trail runs cold, since I was recently just snoping around these areas.

StephanTLavavej commented

We don't use Boost.Math for <complex>'s inverse trig functions; our use is restricted to [sf.cmath].

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ckormanyos commented

We don't use Boost.Math for <complex>'s inverse trig functions; our use is restricted to [sf.cmath].

Cool

ckormanyos commented

Are we sure that 1) these don't work with multiprecision

No, personally I'm really unsure of that.

Just about every floating-point backend includes the headers when Boost.Math is available. If this is absolutely necessary, I'm not sure.

Wouldn't we need to modify these backends in Multiprecision if deprecation ensues? or did i miss the obvious, as I may have and sometimes do?

jzmaddock commented

No std::complex can not be used for multiprecision types. But... the scalar versions for float/double/long double could well be deprecated I guess. Does that make things worse/less generic though?