xreducer¶
Defined in xtensor/xreducer.hpp
- template <class F, class CT, class X>
-
class
xt::
xreducer
¶ Reducing function operating over specified axes.
The xreducer class implements an xexpression applying a reducing function to an xexpression over the specified axes.
- See
- reduce
- Template Parameters
F
: the function typeCT
: the closure type of the xexpression to reduceX
: the list of axes
Inherits from xt::xexpression< xreducer< F, CT, X > >, xt::xexpression_const_iterable< xreducer< F, CT, X > >
Constructor
- template <class Func, class CTA, class AX>
-
xreducer
(Func &&func, CTA &&e, AX &&axes)¶ Constructs an xreducer expression applying the specified function to the given expression over the given axes.
- Parameters
func
: the function to applye
: the expression to reduceaxes
: the axes along which the reduction is performed
Size and shape
-
auto
size
() const¶ Returns the size of the expression.
-
auto
dimension
() const¶ Returns the number of dimensions of the expression.
-
auto
shape
() const¶ Returns the shape of the expression.
-
layout_type
layout
() const¶ Returns the shape of the expression.
Data
-
auto
operator[]
(const xindex &index) const¶ Returns a constant reference to the element at the specified position in the reducer.
- Parameters
index
: a sequence of indices specifying the position in the reducer. Indices must be unsigned integers, the number of indices in the sequence should be equal or greater than the number of dimensions of the reducer.
- template <class... Args>
-
auto
operator()
(Args... args) const¶ Returns a constant reference to the element at the specified position in the reducer.
- Parameters
args
: a list of indices specifying the position in the reducer. Indices must be unsigned integers, the number of indices should be equal or greater than the number of dimensions of the reducer.
- template <class It>
-
auto
element
(It first, It last) const¶ Returns a constant reference to the element at the specified position in the reducer.
- Parameters
first
: iterator starting the sequence of indiceslast
: iterator ending the sequence of indices The number of indices in the sequence should be equal to or greater than the number of dimensions of the reducer.
Broadcasting
- template <class S>
-
bool
broadcast_shape
(S &shape) const¶ Broadcast the shape of the reducer to the specified parameter.
- Return
- a boolean indicating whether the broadcasting is trivial
- Parameters
shape
: the result shape
- template <class S>
-
bool
is_trivial_broadcast
(const S &strides) const¶ Compares the specified strides with those of the container to see whether the broadcasting is trivial.
- Return
- a boolean indicating whether the broadcasting is trivial
- template <class F, class E, class X>
-
auto
xt::
reduce
(F &&f, E &&e, X &&axes)¶ Returns an xexpression applying the speficied reducing function to an expresssion over the given axes.
The returned expression either hold a const reference to
e
or a copy depending on whethere
is an lvalue or an rvalue.- Parameters
f
: the reducing function to apply.e
: the xexpression to reduce.axes
: the list of axes.