ptypy.engines.utils.reduce_dimension

ptypy.engines.utils.reduce_dimension(a, dim, local_indices=None)

Apply a low-rank approximation on a.

Parameters:

• a (ndarray) – 3D numpy array

• dim (int) – The number of dimensions to retain. The case dim=0 (which would just reduce all layers to a mean) is not implemented.

• local_indices – Used for Containers distributed across nodes. Local indices of the current node.

Returns:

where:

• reduced array is the result of dimensionality reduction (same shape as a)

• modes: 3D array of length dim containing eigenmodes (aka singular vectors)

• coefficients: 2D matrix representing the decomposition of a.

Return type:

reduced array, modes, coefficients