joshua/compress
Archived
1
Fork 0
Code Activity

Adds complete wavelet algorithm

Browse source
This commit is contained in:
Joshua Moerman 2013-12-01 21:27:25 +01:00
parent 82896f161a
commit ea705aedc1
2 changed files with 18 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
wavelet/wavelet2.hpp
View file

@ -13,17 +13,18 @@
*
* But also less abstract (which can be both a good thing and bad thing)
*
* wavelet function does not shuffle!
*/
namespace wvlt{
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];
}
// will overwrite x, x1 and x2 are next elements, or wrap around
// 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);
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
// 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);
for(int i = size - 2*stride; i >= 2*stride; i -= 2*stride){
@ -58,5 +59,19 @@ namespace wvlt{
x[i] = y1;
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 Normal file
View file