24 lines
755 B
C++
24 lines
755 B
C++
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#include <vector>
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#include <complex>
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#define POCKETFFT_CACHE_SIZE (16*1024*1024)
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#define POCKETFFT_NO_MULTITHREADING // MT doesn't seem to help at small sizes
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#include <pocketfft_hdronly.h>
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void fft_mag(std::complex<float>* in, float* out, size_t len)
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{
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pocketfft::shape_t shape{len};
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pocketfft::stride_t stride(1);
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stride[0] = sizeof(std::complex<float>);
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pocketfft::shape_t axes;
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axes.push_back(0);
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std::vector<std::complex<float>> out_rev(len);
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pocketfft::c2c(shape, stride, stride, axes, pocketfft::FORWARD, in, out_rev.data(), 1.0f);
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// negative frequencies first
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for(size_t i=0;i<len/2;i++)
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out[i] = abs(out_rev[i + len/2]);
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for(size_t i=0;i<len/2;i++)
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out[i + len/2] = abs(out_rev[i]);
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}
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