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@ -13,17 +13,18 @@ |
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* |
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* But also less abstract (which can be both a good thing and bad thing) |
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* |
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* wavelet function does not shuffle! |
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*/ |
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namespace wvlt{ |
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inline namespace V2 { |
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double inner_product(double* x, double const* coef, unsigned int stride){ |
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inline double inner_product(double* x, double const* coef, unsigned int stride){ |
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return x[0] * coef[0] + x[stride] * coef[1] + x[2*stride] * coef[2] + x[3*stride] * coef[3]; |
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} |
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// will overwrite x, x1 and x2 are next elements, or wrap around
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// size is size of vector x (so x[size-1] is valid)
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void wavelet_mul(double* x, double x1, double x2, unsigned int size, unsigned int stride){ |
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inline void wavelet_mul(double* x, double x1, double x2, unsigned int size, unsigned int stride){ |
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assert(is_pow_of_two(size) && is_pow_of_two(stride) && 4*stride <= size); |
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for(int i = 0; i < size - 2*stride; i += 2*stride){ |
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@ -42,7 +43,7 @@ namespace wvlt{ |
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// will overwrite x, x2 and x1 are previous elements, or wrap around
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// size is size of vector x (so x[size-1] is valid)
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void wavelet_inv(double* x, double x1, double x2, unsigned int size, unsigned int stride){ |
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inline void wavelet_inv(double* x, double x1, double x2, unsigned int size, unsigned int stride){ |
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assert(is_pow_of_two(size) && is_pow_of_two(stride) && 4*stride <= size); |
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for(int i = size - 2*stride; i >= 2*stride; i -= 2*stride){ |
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@ -58,5 +59,19 @@ namespace wvlt{ |
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x[i] = y1; |
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x[i+stride] = y2; |
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} |
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inline void wavelet(double* x, unsigned int size){ |
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assert(is_pow_of_two(size) && size >= 4); |
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for(int i = 1; i <= size / 4; i <<= 1){ |
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wavelet_mul(x, x[0], x[i], size, i); |
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} |
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} |
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inline void unwavelet(double* x, unsigned int size){ |
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assert(is_pow_of_two(size) && size >= 4); |
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for(int i = size / 4; i >= 1; i >>= 1){ |
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wavelet_inv(x, x[size-i], x[size-2*i], size, i); |
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} |
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} |
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} |
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} |
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