extract: Extract or Replace Parts of a Distributed Matrix

In wrathematics/pbdDMAT: 'pbdR' Distributed Matrix Methods

Extract or Replace Parts of a Distributed Matrix

Description

Operators to extract or replace parts of a distributed matrix.

Usage

## S4 method for signature 'ddmatrix'
x[i, j, ICTXT]

Arguments

x	numeric distributed matrix.
i, j	indices specifying elements to extract or replace. Indices can be numeric, character, empty, or NULL. number of elements for a vector (including lists), rows for a matrix or data frame or lines for a function. If negative, all but the n last/first number of elements of x.
ICTXT	optional BLACS context number for output

Details

[ can be used to extract/replace for a distributed matrix exactly as you would with an ordinary matrix.

The functions rely on reblocking across different BLACS contexts. If i is not empty, then the input distributed matrix will be redistributed along context 1, where extracting/deleting rows does not destroy block-cyclicality. Likewise, if j is not empty, then the input distributed matrix will be redistributed along context 2. When extraction is complete, the matrix will be redistributed across its input context.

Value

Returns a distributed matrix.

wrathematics/pbdDMAT documentation built on Oct. 2, 2024, 2:56 p.m.