ArrayUtil

namespace ndarray

namespace arrayutil

Functions

ndarray::LL getNumOfElementByShape(const ndarray::Shape &shape)

get array size or number of element by array shape.

Example: shape{2,3,4} => output 2*3*4 = 24

Return

number of element of given array.

Parameters

• shape: vector data of array shape.

ndarray::Shape getCumulativeMultiShape(const ndarray::Shape &shape, const int offset = 0)

get cumulative multyping shape. output size should be same as shape_size.

Example 1: shape{2,3,4} => cum_shape{12,4,1}

Example 2: shape{2,3,4,5}, offset = 2 => cun_shape{3,1}

Example 3: Shape{2,3}, offset=1 => cum_shape{1}

Return

vector data with cumulative multyping shape likse as stride.

Parameters

• shape: vector data of array shape.

• offset: skip number of element from last of the shape.

ndarray::Shape getMatmulOutShape(const ndarray::Shape &l_shape, const ndarray::Shape &r_shape)

get matmul expected output shape from two array shape. Also support broad castring. Example: l_shape{4,1,3,4}, r_shape{1,3,4,5} => out_shape{4,3,3,5}

Return

Expected broad casted matmul shape.

Parameters

• l_shape: left array shape.

• r_shape: right array shape.

ndarray::LL getIndexFromIndices(const ndarray::Indices &indices, const ndarray::Array &A)

calculate actula location of the given indices

Example: indices{0,1} of a 2D array. output will be that row and column actual location in 1D array.

Return

actual location of that indices.

Parameters

• indices: a vector of indices. size must be same as ndarray shape size.

• A: a ndarray.