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sindexOfColumn

NPM version Build Status Coverage Status

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

Installation

npm install @stdlib/blas-ext-base-sindex-of-column

Alternatively,

  • To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
  • If you are using Deno, visit the deno branch (see README for usage intructions).
  • For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var sindexOfColumn = require( '@stdlib/blas-ext-base-sindex-of-column' );

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

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );

var x = new Float32Array( [ 2.0, 4.0, 0.0 ] );
var workspace = new Uint8Array( 2 );
var out = sindexOfColumn( 'row-major', 3, 2, A, 2, 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 Float32Array.
  • LDA: stride length for the first dimension of A (a.k.a., leading dimension of the matrix A).
  • x: search vector stored as a Float32Array.
  • strideX: stride length for x.
  • workspace: workspace array stored as a Uint8Array for tracking column match candidates. This parameter is ignored if the function is provided an input matrix stored in column-major order.
  • strideW: stride length for workspace.

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

/*
    A = [
        [ 1.0, 3.0 ],
        [ 2.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float32Array( [ 1.0, 2.0, 0.0, 3.0, 4.0, 0.0 ] );

var x = new Float32Array( [ 3.0, 4.0, 0.0 ] );
var workspace = new Uint8Array( 0 );
var out = sindexOfColumn( 'column-major', 3, 2, A, 3, x, 1, workspace, 1 );
// returns 1

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );

var x = new Float32Array( [ -2.0, -4.0, 0.0 ] );
var workspace = new Uint8Array( 2 );
var out = sindexOfColumn( 'row-major', 3, 2, A, 2, x, 1, workspace, 1 );
// returns -1

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

// Initial arrays:
var A0 = new Float32Array( [ 9999.0, 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );
var x0 = new Float32Array( [ 9999.0, 2.0, 4.0, 0.0 ] );

// Create offset views:
var A1 = new Float32Array( A0.buffer, A0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

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

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

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );

var x = new Float32Array( [ 2.0, 4.0, 0.0 ] );
var workspace = new Uint8Array( 2 );
var out = sindexOfColumn.ndarray( 3, 2, A, 2, 1, 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 Float32Array.
  • strideA1: stride length for the first dimension of A.
  • strideA2: stride length for the second dimension of A.
  • offsetA: starting index for A.
  • x: search vector stored as a Float32Array.
  • strideX: stride length for x.
  • offsetX: starting index for x.
  • workspace: workspace array stored as a Uint8Array for tracking column match candidates. This parameter is ignored if the function is provided an input matrix stored in column-major order.
  • strideW: stride length for workspace.
  • offsetW: starting index for workspace.

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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );

var A = new Float32Array( [ 1.0, 2.0, 0.0, 3.0, 4.0, 0.0 ] );

var x = new Float32Array( [ 3.0, 4.0, 0.0 ] );
var workspace = new Uint8Array( 0 );
var out = sindexOfColumn.ndarray( 3, 2, A, 1, 3, 0, x, 1, 0, workspace, 1, 0 );
// returns 1

Notes

  • If M <= 0 or N <= 0, both functions return -1.
  • When searching for a matching column, 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

var Float32Array = require( '@stdlib/array-float32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var ndarray2array = require( '@stdlib/ndarray-base-to-array' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var sindexOfColumn = require( '@stdlib/blas-ext-base-sindex-of-column' );

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

var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 ] );
console.log( ndarray2array( A, shape, strides, 0, order ) );

var x = new Float32Array( [ 2.0, 5.0, 8.0 ] );
console.log( x );

var workspace = new Uint8Array( shape[ 1 ] );

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

C APIs

Usage

#include "stdlib/blas/ext/base/sindex_of_column.h"

stdlib_strided_sindex_of_column( order, M, N, *A, LDA, *X, strideX, *workspace, strideW )

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

#include "stdlib/blas/base/shared.h"
#include <stdint.h>

const float A[] = { 1.0f, 2.0f, 3.0f, 4.0f, 0.0f, 0.0f };
const float x[] = { 2.0f, 4.0f, 0.0f };
uint8_t workspace[ 2 ];

int idx = stdlib_strided_sindex_of_column( CblasRowMajor, 3, 2, A, 2, x, 1, workspace, 1 );
// returns 1

The function accepts the following arguments:

  • order: [in] CBLAS_LAYOUT storage layout.
  • M: [in] CBLAS_INT number of rows in A.
  • N: [in] CBLAS_INT number of columns in A.
  • A: [in] float* input matrix.
  • LDA: [in] CBLAS_INT stride length for the first dimension of A (a.k.a., leading dimension of the matrix A).
  • X: [in] float* search vector.
  • strideX: [in] CBLAS_INT stride length for X.
  • workspace: [inout] uint8_t* workspace array for tracking column match candidates. This parameter is ignored if the function is provided an input matrix stored in column-major order.
  • strideW: [in] CBLAS_INT stride length for workspace.

When an input matrix is stored in column-major order, the workspace parameter is ignored, and, thus, one may either provide an empty workspace array or a NULL pointer.

#include "stdlib/blas/base/shared.h"

const float A[] = { 1.0f, 2.0f, 0.0f, 3.0f, 4.0f, 0.0f };
const float x[] = { 3.0f, 4.0f, 0.0f };

int idx = stdlib_strided_sindex_of_column( CblasColMajor, 3, 2, A, 3, x, 1, NULL, 1 );
// returns 1
CBLAS_INT stdlib_strided_sindex_of_column( const CBLAS_LAYOUT order, const CBLAS_INT M, const CBLAS_INT N, const float *A, const CBLAS_INT LDA, const float *X, const CBLAS_INT strideX, uint8_t *workspace, const CBLAS_INT strideW );

stdlib_strided_sindex_of_column_ndarray( M, N, *A, strideA1, strideA2, offsetA, *X, strideX, offsetX, *workspace, strideW, offsetW )

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

#include <stdint.h>

const float A[] = { 1.0f, 2.0f, 3.0f, 4.0f, 0.0f, 0.0f };
const float x[] = { 2.0f, 4.0f, 0.0f };
uint8_t workspace[ 2 ];

int idx = stdlib_strided_sindex_of_column_ndarray( 3, 2, A, 2, 1, 0, x, 1, 0, workspace, 1, 0 );
// returns 1

The function accepts the following arguments:

  • M: [in] CBLAS_INT number of rows in A.
  • N: [in] CBLAS_INT number of columns in A.
  • A: [in] float* input matrix.
  • strideA1: [in] CBLAS_INT stride length for the first dimension of A.
  • strideA2: [in] CBLAS_INT stride length for the second dimension of A.
  • offsetA: [in] CBLAS_INT starting index for A.
  • X: [in] float* search vector.
  • strideX: [in] CBLAS_INT stride length for X.
  • offsetX: [in] CBLAS_INT starting index for X.
  • workspace: [inout] uint8_t* workspace array for tracking column match candidates. This parameter is ignored if the function is provided an input matrix stored in column-major order.
  • strideW: [in] CBLAS_INT stride length for workspace.
  • offsetW: [in] CBLAS_INT starting index for workspace.

When an input matrix is stored in column-major order, the workspace parameter is ignored, and, thus, one may either provide an empty workspace array or a NULL pointer.

const float A[] = { 1.0f, 2.0f, 0.0f, 3.0f, 4.0f, 0.0f };
const float x[] = { 3.0f, 4.0f, 0.0f };

int idx = stdlib_strided_sindex_of_column_ndarray( 3, 2, A, 1, 3, 0, x, 1, 0, NULL, 1, 0 );
// returns 1
CBLAS_INT stdlib_strided_sindex_of_column_ndarray( const CBLAS_INT M, const CBLAS_INT N, const float *A, const CBLAS_INT strideA1, const CBLAS_INT strideA2, const CBLAS_INT offsetA, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, uint8_t *workspace, const CBLAS_INT strideW, const CBLAS_INT offsetW );

Examples

#include "stdlib/blas/ext/base/sindex_of_column.h"
#include "stdlib/blas/base/shared.h"
#include <stdio.h>

int main( void ) {
    // Create a matrix (column-major):
    const float A[] = { 1.0f, 2.0f, 0.0f, 3.0f, 4.0f, 0.0f, 5.0f, 6.0f, 0.0f };

    // Create a search vector:
    const float x[] = { 3.0f, 4.0f, 0.0f };

    // Specify the number of matrix rows and columns:
    const int M = 3;
    const int N = 3;

    // Perform a search:
    int idx = stdlib_strided_sindex_of_column( CblasColMajor, M, N, A, M, x, 1, NULL, 1 );

    // Print the result:
    printf( "index value: %d\n", idx );
}

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, 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.

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License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.

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

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