Re: [boost] [GSoC 2014] [ Hypergeometric functions ] [ Complex Numbers Calculations ]

I am Cosmin Boaca and I want to work during GSoC 2014 at the hypergeometric functions project.

Hi Cosmin, Thank you for your interest in the project and also for the work you have already put in while researching and prototyping this project.

My first question is : is there a way to do this operations using boost::multiprecision types such as cpp_dec_float and cpp_bin_float in order to store the real and the imaginary part of the complex number ?

That is a good question. The C++ standard specifies the behavior of <complex> for the built-in types float, double, and long double, and *only* for these types. At the same time, Boost does not yet have an extended complex class for supporting complex calculations with user-defined floating-point types such as those in Boost.Multiprecision. There is a proposal for an extended complex class, but we have not had the opportunity to review it yet. So if complex calculations are to be used in Boost.Math, then we would need to find some sensible way to do these --- and I am not talking about breaking the complex numbers into real and imaginary constituents and performing the operations manually. This would not be a sensible use of development time.

The second question is : Can I use the complex functions from the cstdfloat branch of Boost.math ?

This is another good question --- and one on the cutting edge of Boost.Math. The experimental support of <complex> in Boost.Math is intended to be used for *exemplary* purposes only when evaluating and assessing the behavior of certain 128-bit floating-point types. We decided to put this support in namespace std because this is where it belongs for these exemplary purposes. But it is not really in the spirit of Boost to extend the std namespace. So even though the template support you find in the cstdfloat branch can handle complex calculations with all extended user-defined floating-point types, it is nopt intended to be used for this in other public areas of Boost. So we might have to find another solution. This is something that I will keep in mind for this upcoming project. Keep up the good work! Cheers, Chris On Monday, March 10, 2014 9:59 PM, Cosmin Boaca wrote: Hello, I am Cosmin Boaca and I want to work during GSoC 2014 at the hypergeometric functions project. The project aims to approximate some hypergeometric functions for real values of their parameters. Even though the final result of the computation will be a real floating point number, some intermediate results would require complex numbers calculations such as the real power of a negative number, the square root of a negative number and also basic operations with complex numbers. My first question is : is there a way to do this operations using boost::multiprecision types such as cpp_dec_float and cpp_bin_float in order to store the real and the imaginary part of the complex number ? The second question is : Can I use the complex functions from the cstdfloat branch of Boost.math ? Thank you, Cosmin Boaca _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost