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Adds complete wavelet algorithm

master
Joshua Moerman 11 years ago
parent
commit
ea705aedc1
  1. 21
      wavelet/wavelet2.hpp
  2. 0
      wavelet/wavelet_test.cpp

21
wavelet/wavelet2.hpp

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

0
wavelet/wavelet_test.cpp