105 lines
1.8 KiB
C++
105 lines
1.8 KiB
C++
#ifndef MIX_HPP
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#define MIX_HPP
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#include <cmath>
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// Use like `Householder<double, 8>::inPlace(data)` - size must be ≥ 1
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template<typename Sample, int size>
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class Householder
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{
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static constexpr Sample multiplier{-2.0/size};
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public:
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static void inPlace(Sample *arr)
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{
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double sum = 0;
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for (int i = 0; i < size; ++i)
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{
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sum += arr[i];
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}
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sum *= multiplier;
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for (int i = 0; i < size; ++i)
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{
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arr[i] += sum;
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}
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};
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};
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// Use like `Hadamard<double, 8>::inPlace(data)` - size must be a power of 2
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template<typename Sample, int size>
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class Hadamard
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{
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public:
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static inline void recursiveUnscaled(Sample * data)
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{
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if (size <= 1)
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{
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return;
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}
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constexpr int hSize = size/2;
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// Two (unscaled) Hadamards of half the size
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Hadamard<Sample, hSize>::recursiveUnscaled(data);
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Hadamard<Sample, hSize>::recursiveUnscaled(data + hSize);
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// Combine the two halves using sum/difference
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for (int i = 0; i < hSize; ++i)
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{
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double a = data[i];
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double b = data[i + hSize];
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data[i] = (a + b);
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data[i + hSize] = (a - b);
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}
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}
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static inline void inPlace(Sample * data)
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{
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recursiveUnscaled(data);
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Sample scalingFactor = std::sqrt(1.0/size);
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for (int c = 0; c < size; ++c)
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{
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data[c] *= scalingFactor;
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}
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}
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};
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template<typename T, uint numCh>
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class Shuffle
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{
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public:
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static inline void outOfPlace(T *in, T *out, const int *shuffle_spec)
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{
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for (int c=0; c < numCh; c++)
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{
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T sign = 1;
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int s = shuffle_spec[c];
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if (s < 0)
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{
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sign = -1;
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s *= -1;
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}
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if (s >= numCh)
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{
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s = 0;
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}
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out[s] = sign * in[c];
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}
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};
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static inline void inPlace(T *data, const int *shuffle_spec)
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{
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T temp[numCh];
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for (int c=0; c < numCh; c++)
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{
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temp[c] = data[c];
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}
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Shuffle<T, numCh>::outOfPlace(temp, data, shuffle_spec);
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};
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};
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#endif
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