# dlib C++ Library - curand_dlibapi.cpp

    // Copyright (C) 2015  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_DNN_CuRAND_CPP_
    #define DLIB_DNN_CuRAND_CPP_

    #ifdef DLIB_USE_CUDA

    #include "curand_dlibapi.h"
    #include <curand.h>
    #include "../string.h"

    static const char* curand_get_error_string(curandStatus_t s)
    {
        switch(s)
        {
            case CURAND_STATUS_NOT_INITIALIZED:
                return "CUDA Runtime API initialization failed.";
            case CURAND_STATUS_LENGTH_NOT_MULTIPLE:
                return "The requested length must be a multiple of two.";
            default:
                return "A call to cuRAND failed";
        }
    }

    // Check the return value of a call to the cuDNN runtime for an error condition.
    #define CHECK_CURAND(call)                                                      \
    do{                                                                              \
        const curandStatus_t error = call;                                         \
        if (error != CURAND_STATUS_SUCCESS)                                        \
        {                                                                          \
            std::ostringstream sout;                                               \
            sout << "Error while calling " << #call << " in file " << __FILE__ << ":" << __LINE__ << ". ";\
            sout << "code: " << error << ", reason: " << curand_get_error_string(error);\
            throw dlib::curand_error(sout.str());                            \
        }                                                                          \
    }while(false)

    namespace dlib
    {
        namespace cuda
        {

        // ----------------------------------------------------------------------------------------

            curand_generator::
            curand_generator(
                unsigned long long seed
            ) : handle(nullptr)
            {
                curandGenerator_t gen;
                CHECK_CURAND(curandCreateGenerator(&gen, CURAND_RNG_PSEUDO_DEFAULT));
                handle = gen;

                CHECK_CURAND(curandSetPseudoRandomGeneratorSeed(gen, seed));
            }

            curand_generator::
            ~curand_generator()
            {
                if (handle)
                {
                    curandDestroyGenerator((curandGenerator_t)handle);
                }
            }

            void curand_generator::
            fill_gaussian (
                tensor& data,
                float mean,
                float stddev
            )
            {
                if (data.size() == 0)
                    return;

                CHECK_CURAND(curandGenerateNormal((curandGenerator_t)handle,
                                            data.device(),
                                            data.size(),
                                            mean,
                                            stddev));
            }

            void curand_generator::
            fill_uniform (
                tensor& data
            )
            {
                if (data.size() == 0)
                    return;

                CHECK_CURAND(curandGenerateUniform((curandGenerator_t)handle, data.device(), data.size()));
            }

            void curand_generator::
            fill (
                cuda_data_ptr<unsigned int>& data
            )
            {
                if (data.size() == 0)
                    return;

                CHECK_CURAND(curandGenerate((curandGenerator_t)handle, data, data.size()));
            }

        // -----------------------------------------------------------------------------------

        }
    }

    #endif // DLIB_USE_CUDA

    #endif // DLIB_DNN_CuRAND_CPP_