npm package: @stdlib/blas-ext-base-gindex-of-row
Description: Return the index of the first row in an input matrix which has the same elements as a provided search vector.
Author: The Stdlib Authors
Latest version: 0.1.1

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# gindexOfRow

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> Return the index of the first row in an input matrix which has the same elements as a provided search vector.

<section class="installation">

## Installation

```bash
npm install @stdlib/blas-ext-base-gindex-of-row
```

</section>

<section class="usage">

## Usage

```javascript
var gindexOfRow = require( '@stdlib/blas-ext-base-gindex-of-row' );
```

#### gindexOfRow( order, M, N, A, LDA, x, strideX )

Returns the index of the first row in an input matrix which has the same elements as a provided search vector.

```javascript
/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ];

var x = [ 3.0, 4.0 ];
var out = gindexOfRow( 'row-major', 3, 2, A, 2, x, 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 as a linear array.
-   **LDA**: stride of the first dimension of `A` (a.k.a., leading dimension of the matrix `A`).
-   **x**: search vector.
-   **strideX**: stride length of `x`.

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

```javascript
var A = [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ];

var x = [ -3.0, -4.0 ];
var out = gindexOfRow( 'row-major', 3, 2, A, 2, x, 1 );
// returns -1
```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.

<!-- eslint-disable stdlib/capitalized-comments -->

```javascript
var Float64Array = require( '@stdlib/array-float64' );

// Initial arrays:
var A0 = new Float64Array( [ 9999.0, 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ] );
var x0 = new Float64Array( [ 9999.0, 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 out = gindexOfRow( 'row-major', 3, 2, A1, 2, x1, 1 );
// returns 1
```

#### gindexOfRow.ndarray( M, N, A, strideA1, strideA2, offsetA, x, strideX, offsetX )

Returns the index of the first row in an input matrix which has the same elements as a provided search vector using alternative indexing semantics.

```javascript
/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = [ 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ];

var x = [ 3.0, 4.0 ];
var out = gindexOfRow.ndarray( 3, 2, A, 2, 1, 0, x, 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 as a linear array.
-   **strideA1**: stride of the first dimension of `A`.
-   **strideA2**: stride of the second dimension of `A`.
-   **offsetA**: starting index for `A`.
-   **x**: search vector.
-   **strideX**: stride length of `x`.
-   **offsetX**: starting index for `x`.

While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, offset parameters support indexing semantics based on starting indices. For example,

```javascript
/*
    A = [
        [ 1.0, 2.0 ],
        [ 3.0, 4.0 ],
        [ 0.0, 0.0 ]
    ]
*/
var A = [ 9999.0, 1.0, 2.0, 3.0, 4.0, 0.0, 0.0 ];

var x = [ 9999.0, 3.0, 4.0 ];
var out = gindexOfRow.ndarray( 3, 2, A, 2, 1, 1, x, 1, 1 );
// returns 1
```

</section>

<!-- /.usage -->

<section class="notes">

## 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.
-   Both functions support array-like objects having getter and setter accessors for array element access (e.g., [`@stdlib/array-base/accessor`][@stdlib/array/base/accessor]).

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint-disable max-len -->

<!-- eslint no-undef: "error" -->

```javascript
var ndarray2array = require( '@stdlib/ndarray-base-to-array' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var gindexOfRow = require( '@stdlib/blas-ext-base-gindex-of-row' );

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

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

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

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

<!-- /.related -->

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* * *

## Notice

This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].

#### Community

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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