/*******************************************************

* Copyright (c) 2015, ArrayFire

* All rights reserved.

*

* This file is distributed under 3-clause BSD license.

* The complete license agreement can be obtained at:

* http://arrayfire.com/licenses/BSD-3-Clause

********************************************************/

#include <arrayfire.h>

#include <gtest/gtest.h>

#include <testHelpers.hpp>

#include <af/dim4.hpp>

#include <af/traits.hpp>

#include <stdexcept>

#include <string>

#include <vector>

using af::array;

using af::cdouble;

using af::cfloat;

using af::dim4;

using af::dtype;

using af::dtype_traits;

using af::fft;

using af::fft2Norm;

using af::fft3Norm;

using af::fftC2R;

using af::fftNorm;

using af::fftR2C;

using af::randu;

using std::abs;

using std::string;

using std::vector;

template<typename T>

class FFT_REAL : public ::testing::Test {};

typedef ::testing::Types<cfloat, cdouble> TestTypes;

TYPED_TEST_CASE(FFT_REAL, TestTypes);

template<int rank>

array fft(const array &in, double norm) {

switch (rank) {

case 1: return fftNorm(in, norm);

case 2: return fft2Norm(in, norm);

case 3: return fft3Norm(in, norm);

default: return in;

}

}

#define MY_ASSERT_NEAR(aa, bb, cc) ASSERT_NEAR(abs(aa), abs(bb), (cc))

template<typename Tc, int rank>

void fft_real(dim4 dims) {

typedef typename dtype_traits<Tc>::base_type Tr;

SUPPORTED_TYPE_CHECK(Tr);

dtype ty = (dtype)dtype_traits<Tr>::af_type;

array a = randu(dims, ty);

bool is_odd = dims[0] & 1;

int dim0 = dims[0] / 2 + 1;

double norm = 1;

for (int i = 0; i < rank; i++) norm *= dims[i];

norm = 1 / norm;

array as = fftR2C<rank>(a, norm);

array af = fft<rank>(a, norm);

vector<Tc> has(as.elements());

vector<Tc> haf(af.elements());

as.host(&has[0]);

af.host(&haf[0]);

for (int j = 0; j < a.elements() / dims[0]; j++) {

for (int i = 0; i < dim0; i++) {

MY_ASSERT_NEAR(haf[j * dims[0] + i], has[j * dim0 + i], 1E-2)

<< "at " << j * dims[0] + i;

}

}

array b = fftC2R<rank>(as, is_odd, 1);

vector<Tr> ha(a.elements());

vector<Tr> hb(a.elements());

a.host(&ha[0]);

b.host(&hb[0]);

for (int j = 0; j < a.elements(); j++) { ASSERT_NEAR(ha[j], hb[j], 1E-2); }

}

TYPED_TEST(FFT_REAL, Even1D) { fft_real<TypeParam, 1>(dim4(1024, 256)); }

TYPED_TEST(FFT_REAL, Odd1D) { fft_real<TypeParam, 1>(dim4(625, 256)); }

TYPED_TEST(FFT_REAL, Even2D) { fft_real<TypeParam, 2>(dim4(1024, 256)); }

TYPED_TEST(FFT_REAL, Odd2D) { fft_real<TypeParam, 2>(dim4(625, 256)); }

TYPED_TEST(FFT_REAL, Even3D) { fft_real<TypeParam, 3>(dim4(32, 32, 32)); }

TYPED_TEST(FFT_REAL, Odd3D) { fft_real<TypeParam, 3>(dim4(25, 32, 32)); }