DKS/src/MIC/MICFFT.cpp

#include "MICFFT.h"
#include<stdio.h>
#include<complex>
#include <time.h>
#include <sys/time.h>

MICFFT::MICFFT(MICBase *base) {
  m_micbase = base;
  m_fftsetup = false;
}

MICFFT::~MICFFT() {
  if (m_fftsetup) {
#pragma offload target(mic:0)
    {
      DftiFreeDescriptor(&FFTHandle_m);
      DftiFreeDescriptor(&handle);
    }
  }
}

//setup fft
int MICFFT::setupFFT(int ndim, int N[3]) {
  //set up FFT engine
#pragma offload target(mic:0) in(N:length(3) DKS_ALLOC DKS_FREE)
  {

    MKL_LONG sizes[3], strides[4];
    sizes[0] = N[0]; sizes[1] = N[1]; sizes[2] = N[2];
    //strides[0] = 0; strides[1] = sizes[1]; strides[2] = 1; strides[3] = sizes[0]*sizes[1];
    strides[0] = 0; strides[1] = sizes[0]*sizes[1]; strides[2] = sizes[0]; strides[3] = 1;

    MKL_LONG dims = 3;
    DftiCreateDescriptor(&(this->getHandle()), DFTI_DOUBLE, DFTI_COMPLEX, dims, sizes);
    DftiSetValue(this->getHandle(), DFTI_INPUT_STRIDES, strides);
    DftiSetValue(this->getHandle(), DFTI_COMPLEX_STORAGE, DFTI_COMPLEX_COMPLEX);
    DftiCommitDescriptor(this->getHandle());

  }

  m_fftsetup = true;
  return DKS_SUCCESS;
}
//BENI:
//setup fft
int MICFFT::setupFFTRC(int ndim, int N[3], double scale) {

  //set up FFT engine for REAL->COMPLEX

#pragma offload target(mic:0) in(N:length(3) DKS_ALLOC DKS_FREE)
  {

    MKL_LONG sizes[3], real_strides[4], complex_strides[4];
    sizes[0] = N[2]; sizes[1] = N[1]; sizes[2] = N[0];
    //real_strides[0] = 0; real_strides[1] = 2*sizes[1]*(sizes[0]/2+1); real_strides[2] = 2*(sizes[0]/2+1); real_strides[3] = 1;
    real_strides[0] = 0; real_strides[1] = sizes[2]*sizes[1]; real_strides[2] = sizes[2]; real_strides[3] = 1;
    //real_strides[0] = 0; real_strides[1] = 1; real_strides[2] = sizes[0]; real_strides[3] = sizes[0]*sizes[1];
    //complex_strides[0] = 0; complex_strides[1] = sizes[1]*(sizes[0]/2+1); complex_strides[2] = (sizes[0]/2+1); complex_strides[3] = 1;
    complex_strides[0] = 0; complex_strides[1] = sizes[1]*(sizes[2]/2+1); complex_strides[2] = (sizes[2]/2+1); complex_strides[3] = 1;
    //complex_strides[0] = 0; complex_strides[2] = (sizes[0]/2+1); complex_strides[3] = sizes[1]*(sizes[0]/2+1); complex_strides[1] = 1;

    MKL_LONG dims = 3;
    DftiCreateDescriptor(&(this->getHandleRC()), DFTI_DOUBLE, DFTI_REAL, dims, sizes);
    DftiSetValue(this->getHandleRC(),DFTI_CONJUGATE_EVEN_STORAGE,  DFTI_COMPLEX_COMPLEX);
    DftiSetValue(this->getHandleRC(), DFTI_PACKED_FORMAT, DFTI_CCE_FORMAT);
    DftiSetValue(this->getHandleRC(), DFTI_PLACEMENT, DFTI_NOT_INPLACE);
    DftiSetValue(this->getHandleRC(), DFTI_INPUT_STRIDES, real_strides);
    DftiSetValue(this->getHandleRC(), DFTI_OUTPUT_STRIDES, complex_strides);
    DftiSetValue(this->getHandleRC(), DFTI_FORWARD_SCALE, scale);			
    DftiCommitDescriptor(this->getHandleRC());

  }

  return DKS_SUCCESS;
}

//BENI:
//setup fft
int MICFFT::setupFFTCR(int ndim, int N[3], double scale) {

  //set up FFT engine for COMPLEX->REAL

#pragma offload target(mic:0) in(N:length(3) DKS_ALLOC DKS_FREE)
  {	
    MKL_LONG sizes[3], real_strides[4], complex_strides[4];
    sizes[0] = N[2]; sizes[1] = N[1]; sizes[2] = N[0];
    //real_strides[0] = 0; real_strides[1] = 2*sizes[1]*(sizes[0]/2+1); real_strides[2] = 2*(sizes[0]/2+1); real_strides[3] = 1;
    real_strides[0] = 0; real_strides[1] = sizes[2]*sizes[1]; real_strides[2] = sizes[2]; real_strides[3] = 1;
    //real_strides[0] = 0; real_strides[1] = 1; real_strides[2] = sizes[0]; real_strides[3] = sizes[0]*sizes[1];
    //complex_strides[0] = 0; complex_strides[1] = sizes[1]*(sizes[0]/2+1); complex_strides[2] = (sizes[0]/2+1); complex_strides[3] = 1;
    complex_strides[0] = 0; complex_strides[1] = sizes[1]*(sizes[2]/2+1); complex_strides[2] = (sizes[2]/2+1); complex_strides[3] = 1;
    //complex_strides[0] = 0; complex_strides[2] = (sizes[0]/2+1); complex_strides[3] = sizes[1]*(sizes[0]/2+1); complex_strides[1] = 1;

    MKL_LONG dims = 3;
    DftiCreateDescriptor(&(this->getHandleCR()), DFTI_DOUBLE, DFTI_REAL, dims, sizes);
    DftiSetValue(this->getHandleCR(),DFTI_CONJUGATE_EVEN_STORAGE,  DFTI_COMPLEX_COMPLEX);
    DftiSetValue(this->getHandleCR(), DFTI_PACKED_FORMAT, DFTI_CCE_FORMAT);
    DftiSetValue(this->getHandleCR(), DFTI_PLACEMENT, DFTI_NOT_INPLACE);
    DftiSetValue(this->getHandleCR(), DFTI_INPUT_STRIDES, complex_strides);
    DftiSetValue(this->getHandleCR(), DFTI_OUTPUT_STRIDES, real_strides);
    DftiSetValue(this->getHandleCR(), DFTI_BACKWARD_SCALE, scale);			
    DftiCommitDescriptor(this->getHandleCR());



  }

  return DKS_SUCCESS;
}

//execute COMPLEX->COMPLEX FFT
int MICFFT::executeFFT(void *mem_ptr, int ndim, int N[3], int streamId, bool forward) {

  _Complex double *ptr = (_Complex double*) mem_ptr;

#pragma offload target(mic:0) in(ptr:length(0) DKS_RETAIN DKS_REUSE) in(forward)
  {
    if (forward)
      DftiComputeForward(this->getHandle(), ptr);
    else
      DftiComputeBackward(this->getHandle(), ptr);
  }

  return DKS_SUCCESS;
}

//execute iFFT
int MICFFT::executeIFFT(void *mem_ptr, int ndim, int N[3], int streamId) {
  return executeFFT(mem_ptr, ndim, N, -1, false);
}

//execute REAL->COMPLEX FFT
int MICFFT::executeRCFFT(void *in_ptr, void *out_ptr, int ndim, int N[3], int streamId) {

  double *real_ptr = (double*) in_ptr;
  //std::complex<double> *compl_ptr = (std::complex<double> *) out_ptr;
  _Complex double *compl_ptr = (_Complex double *) out_ptr;
  int sizereal = N[0]*N[1]*N[2];
  int sizecompl = (N[0]/2+1)*N[1]*N[2];

//std::cout << "start real-compl fft on mic " << std::endl;
	
  //std::cout << "real_ptr = " << real_ptr << std::endl;
  //std::cout << "compl_ptr = " << compl_ptr << std::endl;
  //std::cout << "EXECUTE AVERAGING OVER 10 LOOPS OF FFT" << std::endl;	

#pragma offload target(mic:0) in(real_ptr:length(0) DKS_RETAIN DKS_REUSE) in(compl_ptr:length(0) DKS_RETAIN DKS_REUSE) 
  //#pragma offload target(mic:0) nocopy(real_ptr:length(sizereal) RETAIN REUSE) nocopy(compl_ptr:length(sizecompl) RETAIN REUSE) 
  {
    //for (int i=0;i<10;++i){ //loop 10 times for benchmarking
      DftiComputeForward(this->getHandleRC(), real_ptr, compl_ptr);
    //}
  }

//std::cout << "end real-compl fft on mic " << std::endl;


  return DKS_SUCCESS;
}

//execute COMPLEX->REAL FFT
int MICFFT::executeCRFFT(void *in_ptr, void *out_ptr, int ndim, int N[3], int streamId) {

  //_Complex double *ptr = (_Complex double*) mem_ptr;

  double *real_ptr = (double*) out_ptr;
  _Complex double *compl_ptr = (_Complex double *) in_ptr;

  //std::cout << "real_ptr = " << real_ptr << std::endl;
  //std::cout << "compl_ptr = " << compl_ptr << std::endl;
  int sizereal = N[0]*N[1]*N[2];
  int sizecompl = (N[0]/2+1)*N[1]*N[2];

  //std::cout << "offload to perform backward fft ... " << std::endl;
//struct timeval start, end;
//gettimeofday(&start,NULL);
#pragma offload target(mic:0) in(real_ptr:length(0) DKS_RETAIN DKS_REUSE) in(compl_ptr:length(0) DKS_RETAIN DKS_REUSE) 
  //#pragma offload target(mic:0) nocopy(real_ptr:length(sizereal) RETAIN REUSE) nocopy(compl_ptr:length(sizecompl) RETAIN REUSE) 
  {
    //for (int i=0;i<10;++i){ //loop 10 times for benchmarking
      DftiComputeBackward(this->getHandleCR(), compl_ptr, real_ptr);
    //}
  }

// End timing offloaded FFT. 
//gettimeofday(&end,NULL);
// Print execution time of offloaded computational loop.
//printf ("Total time for IFFT spent = %f seconds\n",
//(double) (end.tv_usec-start.tv_usec) /1000000+(double) (end.tv_sec-start.tv_sec));
  //std::cout << "IFFT DONE!" << std::endl;
  return DKS_SUCCESS;
}


//normalize IFFT
int MICFFT::normalizeFFT(void *mem_ptr, int ndim, int N[3], int streamId) {

  int size = N[0] * N[1] * N[2];

  _Complex double *ptr = (_Complex double*) mem_ptr;
#pragma offload target(mic:0) in(ptr:length(0) DKS_RETAIN DKS_REUSE) in(size)
  {
#pragma omp parallel for		       
    for (int i = 0; i < size; i++) {
      __real__ ptr[i] = __real__ ptr[i] / size;
      __imag__ ptr[i] = __imag__ ptr[i] / size;
    }  
  }

  return DKS_SUCCESS;

}