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119 lines
2.5 KiB
C++
119 lines
2.5 KiB
C++
// To use the simple FFT implementation
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// g++ -o demofft -I.. -Wall -O3 FFT.cpp
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// To use the FFTW implementation
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// g++ -o demofft -I.. -DUSE_FFTW -Wall -O3 FFT.cpp -lfftw3 -lfftw3f -lfftw3l
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#ifdef USE_FFTW
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#include <fftw3.h>
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#endif
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#include <vector>
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#include <complex>
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#include <algorithm>
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#include <iterator>
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#include <iostream>
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#include <Eigen/Core>
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#include <unsupported/Eigen/FFT>
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using namespace std;
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using namespace Eigen;
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template <typename T>
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T mag2(T a)
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{
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return a*a;
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}
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template <typename T>
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T mag2(std::complex<T> a)
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{
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return norm(a);
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}
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template <typename T>
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T mag2(const std::vector<T> & vec)
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{
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T out=0;
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for (size_t k=0;k<vec.size();++k)
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out += mag2(vec[k]);
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return out;
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}
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template <typename T>
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T mag2(const std::vector<std::complex<T> > & vec)
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{
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T out=0;
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for (size_t k=0;k<vec.size();++k)
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out += mag2(vec[k]);
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return out;
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}
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template <typename T>
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vector<T> operator-(const vector<T> & a,const vector<T> & b )
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{
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vector<T> c(a);
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for (size_t k=0;k<b.size();++k)
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c[k] -= b[k];
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return c;
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}
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template <typename T>
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void RandomFill(std::vector<T> & vec)
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{
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for (size_t k=0;k<vec.size();++k)
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vec[k] = T( rand() )/T(RAND_MAX) - .5;
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}
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template <typename T>
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void RandomFill(std::vector<std::complex<T> > & vec)
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{
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for (size_t k=0;k<vec.size();++k)
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vec[k] = std::complex<T> ( T( rand() )/T(RAND_MAX) - .5, T( rand() )/T(RAND_MAX) - .5);
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}
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template <typename T_time,typename T_freq>
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void fwd_inv(size_t nfft)
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{
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typedef typename NumTraits<T_freq>::Real Scalar;
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vector<T_time> timebuf(nfft);
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RandomFill(timebuf);
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vector<T_freq> freqbuf;
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static FFT<Scalar> fft;
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fft.fwd(freqbuf,timebuf);
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vector<T_time> timebuf2;
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fft.inv(timebuf2,freqbuf);
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long double rmse = mag2(timebuf - timebuf2) / mag2(timebuf);
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cout << "roundtrip rmse: " << rmse << endl;
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}
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template <typename T_scalar>
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void two_demos(int nfft)
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{
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cout << " scalar ";
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fwd_inv<T_scalar,std::complex<T_scalar> >(nfft);
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cout << " complex ";
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fwd_inv<std::complex<T_scalar>,std::complex<T_scalar> >(nfft);
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}
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void demo_all_types(int nfft)
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{
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cout << "nfft=" << nfft << endl;
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cout << " float" << endl;
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two_demos<float>(nfft);
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cout << " double" << endl;
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two_demos<double>(nfft);
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cout << " long double" << endl;
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two_demos<long double>(nfft);
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}
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int main()
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{
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demo_all_types( 2*3*4*5*7 );
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demo_all_types( 2*9*16*25 );
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demo_all_types( 1024 );
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return 0;
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}
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