gistfile1.md

This is my implementation of tanh for CUDA:

#include <iostream>
#include <math.h>
#include <cuComplex.h>
#include <complex>

typedef double     rtype;
typedef cuDoubleComplex ctype;
#define rpart(x)   (cuCreal(x))
#define ipart(x)   (cuCimag(x))
#define cmplx(x,y) (make_cuDoubleComplex(x,y))
#define cneg(x) (cuCmul(make_cuDoubleComplex(-1.0,0.0), x))


__host__ __device__ ctype cexp(ctype z) {
   ctype res;
   rtype s, c;
   rtype e = exp(rpart(z));
   sincos(ipart(z), &s, &c);
   res.x = c * e;
   res.y = s * e;
   return res;
}

__host__ __device__ ctype ctanh(const ctype& z) {
  return cuCdiv(cuCsub(cexp(z), cexp(cneg(z))) , cuCadd(cexp(z) , cexp(cneg(z))));
  }

int main(){

  double r = 0.5;
  double i = 0.5;

  std::complex<double> cpu_num(r,i);
  ctype cu_num = cmplx(r,i);

  std::complex<double> cpu_ans = std::tanh(cpu_num);
  ctype cu_ans = ctanh(cu_num);

  std::cout << "CPU real: " << std::real(cpu_ans) << " CPU imag: " << std::imag(cpu_ans) << std::endl;
  std::cout << "GPU real: " << rpart(cu_ans) << " GPU  imag: " << ipart(cu_ans) << std::endl;
  return 0;
}

save it as test.cu

compile like so:

nvcc -arch=sm_20 -O3 -o test test.cu

run it:

./test

and output is:

CPU real: 0.564083 CPU imag: 0.403896
GPU real: 0.564083 GPU  imag: 0.403896