test_fft.cc
d147e5fb3242master

test_fft.cc
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			#include "my_types.hh"
			#include "fft.hh"
			#include <gtest/gtest.h>

			/*****************************************************************/
			TEST(FFT, transform) {
			UInt N = 512;
			Matrix<complex> m(N);

			Real k = 2 * M_PI / N;
			for (auto&& entry : index(m)) {
			int i = std::get<0>(entry);
			int j = std::get<1>(entry);
			auto& val = std::get<2>(entry);
			val = cos(k * i);
			}

			Matrix<complex> res = FFT::transform(m);

			for (auto&& entry : index(res)) {
			int i = std::get<0>(entry);
			int j = std::get<1>(entry);
			auto& val = std::get<2>(entry);
			if (std::abs(val) > 1e-10)
			std::cout << i << "," << j << " = " << val << std::endl;

			if (i == 1 && j == 0)
			ASSERT_NEAR(std::abs(val), N * N / 2, 1e-10);
			else if (i == N - 1 && j == 0)
			ASSERT_NEAR(std::abs(val), N * N / 2, 1e-10);
			else
			ASSERT_NEAR(std::abs(val), 0, 1e-10);
			}
			}
			/*****************************************************************/

			TEST(FFT, inverse_transform) {
			}
			/*****************************************************************/