Index related functions — xtensor documentation (original) (raw)

Defined in xtensor/core/xoperation.hpp

template<class T>
inline auto xt::where(const T &condition)

return vector of indices where condition is true (equivalent to nonzero(condition))

Parameters:

condition – input array

Returns:

vector of index_types where condition is not equal to zero

template<class T>
inline auto xt::nonzero(const T &arr)

return vector of indices where T is not zero

Parameters:

arr – input array

Returns:

vector of vectors, one for each dimension of arr, containing the indices of the non-zero elements in that dimension

template<layout_type L = ::xt::layout_type::row_major, class T>
inline auto xt::argwhere(const T &arr)

return vector of indices where arr is not zero

Template Parameters:

L – the traversal order

Parameters:

arr – input array

Returns:

vector of index_types where arr is not equal to zero (use [xt::from_indices](xtensor.html#namespacext%5F1ade2d67c70b0ec6af8294f4b7f201a722) to convert)

template<class T>
inline auto xt::from_indices(const std::vector<T> &idx)

Converts std::vector<index_type> (returned e.g.

from [xt::argwhere](#group%5F%5Flogical%5F%5Foperators%5F1ga8e8213a0ec55abe31dc046b6a03379d7)) to xtensor.

Parameters:

idx – vector of indices

Returns:

[xt::xtensor](xtensor.html#namespacext%5F1a29d0a2d76c0f69cf43aa3b4f55a7a26d)<typename index_type::value_type, 2> (e.g. [xt::xtensor](xtensor.html#namespacext%5F1a29d0a2d76c0f69cf43aa3b4f55a7a26d)<size_t, 2>)