complex_vec_t fourier_transform::backwards(const complex_vec_t &in, size_t n) const
{
if(n==0){
n=in.size();
}else{
if(n>in.size())
throw std::invalid_argument("Output size must be less than or equal to input size.");
}
complex_vec_t result(in.size());
complex_t wn=root_of_unity(n);
backwards_impl(n, wn, &in[0], 1, &result[0], 1);
result.resize(n);
return result;
}
/**
* computes element-by-element division of two matrices (matrix1 / matrix2) into result
*/
bool mat_dot_div(unsigned int nx1, unsigned int ny1, unsigned int nz1,
const complex_vec_t& matrix1,
unsigned int nx2, unsigned int ny2, unsigned int nz2,
const complex_vec_t& matrix2,
complex_vec_t& result) {
if(nx1 != nx2 || ny1 != ny2 || nz1 != nz2 || matrix1.size() != matrix2.size()) {
std::cerr << "error: matrix sizes are not the same for dot division operation"
<< std::endl;
return false;
} // if
result.clear();
complex_vec_t::const_iterator i1 = matrix1.begin();
complex_vec_t::const_iterator i2 = matrix2.begin();
for(; i1 != matrix1.end(); ++ i1, ++ i2) {
result.push_back((*i1) / (*i2));
} // for
return true;
} // mat_dot_div()
complex_vec_t fourier_transform::forwards(const complex_vec_t &in) const
{
size_t n=calc_padded_size(in.size());
complex_vec_t result(n);
complex_t wn=root_of_unity(n);
if(n==in.size()){
forwards_impl(n, wn, &in[0], 1, &result[0], 1);
}else{
complex_vec_t buffer(in);
buffer.resize(n, complex_t(0.0,0.0) );
forwards_impl(n, wn, &buffer[0], 1, &result[0], 1);
}
return result;
}
/**
* computes element-by-element product of two matrices into result
*/
bool mat_dot_prod(unsigned int x1_size, unsigned int y1_size, unsigned int z1_size,
const complex_vec_t& matrix1,
unsigned int x2_size, unsigned int y2_size, unsigned int z2_size,
const complex_vec_t& matrix2,
complex_vec_t& result) {
if(x1_size != x2_size || y1_size != y2_size || z1_size != z2_size
|| matrix1.size() != matrix2.size()) {
std::cerr << "error: matrix sizes are not the same for dot product operation" << std::endl;
return false;
} // if
result.clear();
complex_vec_t::const_iterator i1 = matrix1.begin();
complex_vec_t::const_iterator i2 = matrix2.begin();
for(; i1 != matrix1.end(); ++ i1, ++ i2) {
result.push_back((*i1) * (*i2));
} // for
return true;
} // mat_dot_prod()