submatrix

1 7.4

A smaller grid of numbers taken from a larger grid by choosing some rows and columns

noun
/sʌbˈmeɪtrɪks/

Specialized

: submatriz

At a given tree level i, all nodes (there are 2^i nodes, each of size m = n_i or m = n_i + 1, where n_i = N/2^i) again execute the Cholesky algorithm on a submatrix of size m.
submatrix of size
block submatrix
submatrix operands

Examples

The other method is to data-copy a small submatrix A in PRLF to a buffer that stores A in full format so that standard linear addressing can be used.

Academic text (2000)
To find the memory location of an element A(i, j) in any triangle submatrix of size 24, a lookup at address alpha i + j less than or equal to 1 and less than or equal to 24 of the map M1 is done.

Academic text (2000)
Also, the majority of the processing is done in calls to DGEMM on submatrix blocks of variable size.

Academic text (2000)
A block of data may be a row or a column of an image, a row or column of a matrix, or it may be a subimage or submatrix depending on the requirements of the application.

Academic text (2000)
To find the memory location of an element in any triangle submatrix of size 23, the kernel performs a lookup at address j + alpha i less than or equal to 1 less than or equal to 24 of the map M2.

Academic text (2000)
The format is a blocked format, which is a special case of the block-cyclic format, and that suggests a key observation: the various calls to the BLAS routines of a dense linear-algebra code encounter the same submatrix operands over and over again.

Academic text (1997)
The no answer refers to perhaps being unable to add the blocked data typed to the FORTRAN or C language and/or to suitably modify the current BLAS to accept blocked submatrix operands.

Academic text (1997)
As a by-product of this work, we have discovered a way to improve a library such as LAPACK by taking advantage of the relationship between submatrix operands of multiple BLAS calls in a LAPACK algorithm. The BLAS routines have to be modified to accept block submatrix operands.

Academic text (1997)
As a by-product of this work, we have discovered a way to improve a library such as LAPACK by taking advantage of the relationship between submatrix operands of multiple BLAS calls in a LAPACK algorithm. The BLAS routines have to be modified to accept block submatrix operands.

Academic text (1997)
In mathematics, a submatrix can be extracted from a larger matrix by selecting specific rows and columns.

Surface Forms

submatrix singular

submatrices plural

Morphology

submatrix = matrix (transparent) = sub + matrix

The prefix 'sub-' meaning 'under/secondary/part of' combines directly with 'matrix' to denote a smaller or constituent matrix, which is readily inferable.

Etymology

The word submatrix breaks into sub- meaning 'under' or 'smaller part', the same sub- you see in submarine and subway, and matrix meaning 'grid' or 'place where things are formed'. So, a submatrix is a smaller grid taken from inside a larger one.