README.md

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dindexOfRow

Return the index of the first row in a double-precision floating-point input matrix which has the same elements as a provided search vector.

Usage

import dindexOfRow from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-dindex-of-row@deno/mod.js';

dindexOfRow( order, M, N, A, LDA, x, strideX, workspace, strideW )

Returns the index of the first row in a double-precision floating-point input matrix which has the same elements as a provided search vector.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

/*
    A = [
        [ 1.0, 3.0 ],
        [ 2.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float64Array( [ 1.0, 2.0, 0.0, 3.0, 4.0, 0.0 ] );

var x = new Float64Array( [ 2.0, 4.0 ] );
var workspace = new Uint8Array( 3 );
var out = dindexOfRow( 'column-major', 3, 2, A, 3, x, 1, workspace, 1 );
// returns 1

The function has the following parameters:

• order: storage layout.
• M: number of rows in A.
• N: number of columns in A.
• A: input matrix stored as a Float64Array.
• LDA: stride of the first dimension of A (a.k.a., leading dimension of the matrix A).
• x: search vector stored as a Float64Array.
• strideX: stride length of x.
• workspace: workspace array stored as a Uint8Array for tracking row match candidates. This parameter is ignored if the function is provided an input matrix stored in row-major order.
• strideW: stride length of workspace.

When an input matrix is stored in row-major order, the workspace parameter is ignored, and, thus, one may provide an empty workspace array.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );

var x = new Float64Array( [ 3.0, 4.0 ] );
var workspace = new Uint8Array( 0 );
var out = dindexOfRow( 'row-major', 3, 2, A, 2, x, 1, workspace, 1 );
// returns 1

If the function is unable to find a matching row, the function returns -1.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

/*
    A = [
        [ 1.0, 3.0 ],
        [ 2.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float64Array( [ 1.0, 2.0, 0.0, 3.0, 4.0, 0.0 ] );

var x = new Float64Array( [ -3.0, -4.0 ] );
var workspace = new Uint8Array( 3 );
var out = dindexOfRow( 'column-major', 3, 2, A, 3, x, 1, workspace, 1 );
// returns -1

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

// Initial arrays:
var A0 = new Float64Array( [ 0.0, 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );
var x0 = new Float64Array( [ 0.0, 3.0, 4.0 ] );

// Create offset views:
var A1 = new Float64Array( A0.buffer, A0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var workspace = new Uint8Array( 0 );
var out = dindexOfRow( 'row-major', 3, 2, A1, 2, x1, 1, workspace, 1 );
// returns 1

dindexOfRow.ndarray( M, N, A, strideA1, strideA2, offsetA, x, strideX, offsetX, workspace, strideW, offsetW )

Returns the index of the first row in a double-precision floating-point input matrix which has the same elements as a provided search vector using alternative indexing semantics.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

/*
    A = [
        [ 1.0, 3.0 ],
        [ 2.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float64Array( [ 1.0, 2.0, 0.0, 3.0, 4.0, 0.0 ] );

var x = new Float64Array( [ 2.0, 4.0 ] );
var workspace = new Uint8Array( 3 );
var out = dindexOfRow.ndarray( 3, 2, A, 1, 3, 0, x, 1, 0, workspace, 1, 0 );
// returns 1

The function has the following parameters:

• M: number of rows in A.
• N: number of columns in A.
• A: input matrix stored as a Float64Array.
• strideA1: stride of the first dimension of A.
• strideA2: stride of the second dimension of A.
• offsetA: starting index for A.
• x: search vector stored as a Float64Array.
• strideX: stride length of x.
• offsetX: starting index for x.
• workspace: workspace array stored as a Uint8Array for tracking row match candidates. This parameter is ignored if the function is provided an input matrix stored in row-major order.
• strideW: stride length of workspace.
• offsetW: starting index for workspace.

When an input matrix is stored in row-major order, the workspace parameter is ignored, and, thus, one may provide an empty workspace array.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';

var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );

var x = new Float64Array( [ 3.0, 4.0 ] );
var workspace = new Uint8Array( 0 );
var out = dindexOfRow.ndarray( 3, 2, A, 2, 1, 0, x, 1, 0, workspace, 1, 0 );
// returns 1

Notes

• When searching for a matching row, the function checks for equality using the strict equality operator ===. As a consequence, NaN values are considered distinct, and -0 and +0 are considered the same.

Examples

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@deno/mod.js';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-base-to-array@deno/mod.js';
import shape2strides from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-base-shape2strides@deno/mod.js';
import dindexOfRow from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-dindex-of-row@deno/mod.js';

var shape = [ 3, 3 ];
var order = 'row-major';
var strides = shape2strides( shape, order );

var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 0.0, 0.0, 0.0 ] );
console.log( ndarray2array( A, shape, strides, 0, order ) );

var x = new Float64Array( [ 4.0, 5.0, 6.0 ] );
console.log( x );

var workspace = new Uint8Array( shape[ 0 ] );

var out = dindexOfRow( order, shape[ 0 ], shape[ 1 ], A, strides[ 0 ], x, 1, workspace, 1 );
console.log( out );

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Notice

This package is part of stdlib, a standard library with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.