xbuilder¶
Defined in xtensor/xbuilder.hpp
- template <class T, class S>
-
auto
xt::
ones
(S shape)¶ Returns an xexpression containing ones of the specified shape.
- Template Parameters
shape
: the shape of the returned expression.
- template <class T, class I, std::size_t L>
-
auto
xt::
ones
(const I (&shape)[L])¶
- template <class T, class S>
-
auto
xt::
zeros
(S shape)¶ Returns an xexpression containing zeros of the specified shape.
- Template Parameters
shape
: the shape of the returned expression.
- template <class T, class I, std::size_t L>
-
auto
xt::
zeros
(const I (&shape)[L])¶
- template <class T = bool>
-
auto
xt::
eye
(const std::vector<std::size_t> &shape, int k = 0)¶ Generates an array with ones on the diagonal.
- Return
- xgenerator that generates the values on access
- Parameters
shape
: shape of the resulting expressionk
: index of the diagonal. 0 (default) refers to the main diagonal, a positive value refers to an upper diagonal, and a negative value to a lower diagonal.
- Template Parameters
T
: value_type of xexpression
- template <class T = bool>
-
auto
xt::
eye
(std::size_t n, int k = 0)¶ Generates a (n x n) array with ones on the diagonal.
- Return
- xgenerator that generates the values on access
- Parameters
n
: length of the diagonal.k
: index of the diagonal. 0 (default) refers to the main diagonal, a positive value refers to an upper diagonal, and a negative value to a lower diagonal.
- Template Parameters
T
: value_type of xexpression
- template <class T>
-
auto
xt::
arange
(T start, T stop, T step = 1)¶ Generates numbers evenly spaced within given half-open interval [start, stop).
- Return
- xgenerator that generates the values on access
- Parameters
start
: start of the intervalstop
: stop of the intervalstep
: stepsize
- Template Parameters
T
: value_type of xexpression
- template <class T>
-
auto
xt::
arange
(T stop)¶ Generate numbers evenly spaced within given half-open interval [0, stop) with a step size of 1.
- Return
- xgenerator that generates the values on access
- Parameters
stop
: stop of the interval
- Template Parameters
T
: value_type of xexpression
- template <class T>
-
auto
xt::
linspace
(T start, T stop, std::size_t num_samples = 50, bool endpoint = true)¶ Generates num_samples evenly spaced numbers over given interval.
- Return
- xgenerator that generates the values on access
- Parameters
start
: start of intervalstop
: stop of intervalnum_samples
: number of samples (defaults to 50)endpoint
: if true, include endpoint (defaults to true)
- Template Parameters
T
: value_type of xexpression
- template <class T>
-
auto
xt::
logspace
(T start, T stop, std::size_t num_samples, T base = 10, bool endpoint = true)¶ Generates num_samples numbers evenly spaced on a log scale over given interval.
- Return
- xgenerator that generates the values on access
- Parameters
start
: start of interval (pow(base, start) is the first value).stop
: stop of interval (pow(base, stop) is the final value, except if endpoint = false)num_samples
: number of samples (defaults to 50)base
: the base of the log space.endpoint
: if true, include endpoint (defaults to true)
- Template Parameters
T
: value_type of xexpression
- template <class E>
-
auto
xt::
diag
(E &&arr, int k = 0)¶ xexpression with values of arr on the diagonal, zeroes otherwise
xt::xarray<double> a = {1, 5, 9}; auto b = xt::diag(a); // => {{1, 0, 0}, // {0, 5, 0}, // {0, 0, 9}}
- Return
- xexpression function with shape n x n and arr on the diagonal
- Parameters
arr
: the 1D input array of length nk
: the offset of the considered diagonal
- template <class E>
-
auto
xt::
diagonal
(E &&arr, int offset = 0, std::size_t axis_1 = 0, std::size_t axis_2 = 1)¶ Returns the elements on the diagonal of arr If arr has more than two dimensions, then the axes specified by axis_1 and axis_2 are used to determine the 2-D sub-array whose diagonal is returned.
The shape of the resulting array can be determined by removing axis1 and axis2 and appending an index to the right equal to the size of the resulting diagonals.
xt::xarray<double> a = {{1, 2, 3}, {4, 5, 6} {7, 8, 9}}; auto b = xt::diagonal(a); // => {1, 5, 9}
- Return
- xexpression with values of the diagonal
- Parameters
arr
: the input arrayoffset
: offset of the diagonal from the main diagonal. Can be positive or negative.axis_1
: Axis to be used as the first axis of the 2-D sub-arrays from which the diagonals should be taken.axis_2
: Axis to be used as the second axis of the 2-D sub-arrays from which the diagonals should be taken.
- template <class E>
-
auto
xt::
tril
(E &&arr, int k = 0)¶ Extract lower triangular matrix from xexpression.
The parameter k selects the offset of the diagonal.
- Return
- xexpression containing lower triangle from arr, 0 otherwise
- Parameters
arr
: the input arrayk
: the diagonal above which to zero elements. 0 (default) selects the main diagonal, k < 0 is below the main diagonal, k > 0 above.
- template <class E>
-
auto
xt::
triu
(E &&arr, int k = 0)¶ Extract upper triangular matrix from xexpression.
The parameter k selects the offset of the diagonal.
- Return
- xexpression containing lower triangle from arr, 0 otherwise
- Parameters
arr
: the input arrayk
: the diagonal below which to zero elements. 0 (default) selects the main diagonal, k < 0 is below the main diagonal, k > 0 above.
- template <class E>
-
auto
xt::
flip
(E &&arr, std::size_t axis)¶ Reverse the order of elements in an xexpression along the given axis.
Note: A NumPy/Matlab style
flipud(arr)
is equivalent toxt::flip(arr, 0)
,fliplr(arr)
toxt::flip(arr, 1)
.- Return
- xexpression evaluating to reversed array
- Parameters
arr
: the input xexpressionaxis
: the axis along which elements should be reversed