/**
* @brief Sum along a dimension
*
* Usage:
* @code
* Matrix<cxfl> m = rand<double> (8,7,6);
* m = sum (m,0); // dims (7,6);
* @endcode
*
* @param M Matrix
* @param d Dimension
* @return Sum of M along dimension d
*/
template <class T> inline static Matrix<T> sum (const MatrixType<T>& M, const size_t& d = 0) {
Vector<size_t> sz = size(M);
size_t dim = sz[d];
Matrix<T> res;
assert (d < M.NDim());
// No meaningful sum over particular dimension
if (dim == 1)
return res;
// Empty? allocation
if (isempty(M))
return res;
// Inner size
size_t insize = 1;
for (size_t i = 0; i < d; ++i)
insize *= sz[i];
// Outer size
size_t outsize = 1;
for (size_t i = d+1; i < std::min(M.NDim(),sz.size()); ++i)
outsize *= sz[i];
// Adjust size vector and allocate
sz [d] = 1;
res = Matrix<T>(sz);
// Sum
#pragma omp parallel default (shared)
{
#pragma omp for
for (int i = 0; i < outsize; ++i) {
for (size_t j = 0; j < insize; ++j) {
res[i*insize + j] = T(0);
for (size_t k = 0; k < dim; ++k)
res[i*insize + j] += M[i*insize*dim + j + k*insize];
}
}
}
return res;
}
/**
* @brief Highest dimension unequal 1
*
* Usage:
* @code
* Matrix<cxfl> m = rand<double> (8,7,6);
* size_t nd = ndims(m); // 2
* @endcode
*
* @param M Matrix
* @return Highest non-one dimension
*/
template <class T> inline static size_t ndims (const MatrixType<T>& M) {
size_t nd = 0;
for (size_t i = 1; i < M.NDim(); ++i)
if (size(M,i) > 1)
nd = i;
return (nd + 1);
}
