scijs/ndarray-blas-gemv

Name: ndarray-blas-gemv

Owner: scijs

Description: BLAS Level 2 GEMV (Matrix-Vector multiply) for ndarrays

Created: 2015-05-14 14:51:30.0

Updated: 2015-11-04 12:57:48.0

Pushed: 2015-05-14 15:01:38.0

Homepage: null

Size: 128

Language: JavaScript

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README

ndarray-blas-gemv

BLAS Level 2 GEMV (matrix-vector multiply) for ndarrays

Usage

gemv( alpha, A, x, beta, y )

Calculate y <- alpha * A * x + beta * y for scalar alpha, matrix A, vector x, scalar beta, and vector y. Result is overwritten in vector y. All other inputs are unchanged.

Example

gemv = require('ndarray-blas-gemv')

A = ndarray([1,2,5,3], [2,2]),
x = ndarray([-4,7]),
y = ndarray([3,-2])

( -4, A, x, 2, y )

esult: y = [-34, -8]

To multiply using the transpose of A, you can simply use .transpose(1,0) to transpose the input (note that this calculates new strides and offsets but does not rearrange the physical memory).

A = ndarray([1,2,5,3], [2,2]),
x = ndarray([-4,7]),
y = ndarray([3,-2])

( -4, A.transpose(1,0), x, 2, y )

esult: y = [-118, -56]

Credits

(c) 2015 Ricky Reusser. MIT License