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Original file line number Diff line number Diff line change
Expand Up @@ -42,25 +42,38 @@ Returns the index of the first falsy element in a one-dimensional ndarray.

```javascript
var vector = require( '@stdlib/ndarray/vector/ctor' );
var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );

var x = vector( [ 1.0, 3.0, 0.0, 2.0 ], 'generic' );

var idx = gindexOfFalsy( [ x ] );
var fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

var idx = gindexOfFalsy( [ x, fromIndex ] );
// returns 2
```

The function has the following parameters:

- **arrays**: array-like object containing a one-dimensional input ndarray.
- **arrays**: array-like object containing the following ndarrays:

- a one-dimensional input ndarray.
- a zero-dimensional ndarray containing the index from which to begin searching.

If the function is unable to find a falsy element, the function returns `-1`.

```javascript
var vector = require( '@stdlib/ndarray/vector/ctor' );
var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );

var x = vector( [ 1.0, 2.0, 3.0, 4.0 ], 'generic' );

var idx = gindexOfFalsy( [ x ] );
var fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

var idx = gindexOfFalsy( [ x, fromIndex ] );
// returns -1
```

Expand All @@ -73,6 +86,7 @@ var idx = gindexOfFalsy( [ x ] );
## Notes

- The function treats `NaN` values as falsy.
- If a specified starting search index is negative, the function resolves the starting search index by counting backward from the last element (where `-1` refers to the last element).

</section>

Expand All @@ -86,6 +100,7 @@ var idx = gindexOfFalsy( [ x ] );

```javascript
var discreteUniform = require( '@stdlib/random/discrete-uniform' );
var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var gindexOfFalsy = require( '@stdlib/blas/ext/base/ndarray/gindex-of-falsy' );

Expand All @@ -96,7 +111,11 @@ var opts = {
var x = discreteUniform( [ 10 ], 0, 5, opts );
console.log( ndarray2array( x ) );

var idx = gindexOfFalsy( [ x ] );
var fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

var idx = gindexOfFalsy( [ x, fromIndex ] );
console.log( idx );
```

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@

var bench = require( '@stdlib/bench' );
var ones = require( '@stdlib/ndarray/ones' );
var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
var isInteger = require( '@stdlib/assert/is-integer' ).isPrimitive;
var pow = require( '@stdlib/math/base/special/pow' );
var format = require( '@stdlib/string/format' );
Expand All @@ -46,7 +47,13 @@ var options = {
* @returns {Function} benchmark function
*/
function createBenchmark( len ) {
var x = ones( [ len ], options );
var fromIndex;
var x;

x = ones( [ len ], options );
fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});
return benchmark;

/**
Expand All @@ -61,7 +68,7 @@ function createBenchmark( len ) {

b.tic();
for ( i = 0; i < b.iterations; i++ ) {
out = gindexOfFalsy( [ x ] );
out = gindexOfFalsy( [ x, fromIndex ] );
if ( out !== out ) {
b.fail( 'should return an integer' );
}
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,10 @@
{{alias}}( arrays )
Returns the index of the first falsy element in a one-dimensional ndarray.

If a specified starting search index is negative, the function resolves the
starting search index by counting backward from the last element (where `-1`
refers to the last element).

If unable to find a falsy element, the function returns `-1`.

Parameters
Expand All @@ -10,6 +14,8 @@
Array-like object containing the following ndarrays:

- a one-dimensional input ndarray.
- a zero-dimensional ndarray containing the index from which to begin
searching.

Returns
-------
Expand All @@ -19,7 +25,8 @@
Examples
--------
> var x = {{alias:@stdlib/ndarray/vector/ctor}}( [ 1.0, 0.0, 3.0 ], 'generic' );
> {{alias}}( [ x ] )
> var i = {{alias:@stdlib/ndarray/from-scalar}}( 0, { 'dtype': 'generic' } );
> {{alias}}( [ x, i ] )
1

See Also
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -30,19 +30,25 @@ import { typedndarray } from '@stdlib/types/ndarray';
* - The function expects the following ndarrays:
*
* - a one-dimensional input ndarray.
* - a zero-dimensional ndarray containing the index from which to begin searching.
*
* @param arrays - array-like object containing ndarrays
* @returns index
*
* @example
* var vector = require( '@stdlib/ndarray/vector/ctor' );
* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
*
* var x = vector( [ 1.0, 3.0, 0.0, 2.0 ], 'generic' );
*
* var v = gindexOfFalsy( [ x ] );
* var fromIndex = scalar2ndarray( 0, {
* 'dtype': 'generic'
* });
*
* var v = gindexOfFalsy( [ x, fromIndex ] );
* // returns 2
*/
declare function gindexOfFalsy( arrays: [ typedndarray<unknown> ] ): number;
declare function gindexOfFalsy( arrays: [ typedndarray<unknown>, typedndarray<number> ] ): number;


// EXPORTS //
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
/* eslint-disable space-in-parens */

import zeros = require( '@stdlib/ndarray/zeros' );
import scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
import gindexOfFalsy = require( './index' );


Expand All @@ -29,8 +30,11 @@ import gindexOfFalsy = require( './index' );
const x = zeros( [ 10 ], {
'dtype': 'generic'
});
const fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

gindexOfFalsy( [ x ] ); // $ExpectType number
gindexOfFalsy( [ x, fromIndex ] ); // $ExpectType number
}

// The compiler throws an error if the function is provided a first argument which is not an array of ndarrays...
Expand All @@ -51,7 +55,10 @@ import gindexOfFalsy = require( './index' );
const x = zeros( [ 10 ], {
'dtype': 'generic'
});
const fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

gindexOfFalsy(); // $ExpectError
gindexOfFalsy( [ x ], {} ); // $ExpectError
gindexOfFalsy( [ x, fromIndex ], {} ); // $ExpectError
}
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
'use strict';

var discreteUniform = require( '@stdlib/random/discrete-uniform' );
var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var gindexOfFalsy = require( './../lib' );

Expand All @@ -29,5 +30,9 @@ var opts = {
var x = discreteUniform( [ 10 ], 0, 5, opts );
console.log( ndarray2array( x ) );

var idx = gindexOfFalsy( [ x ] );
var fromIndex = scalar2ndarray( 0, {
'dtype': 'generic'
});

var idx = gindexOfFalsy( [ x, fromIndex ] );
console.log( idx );
Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,16 @@
*
* @example
* var vector = require( '@stdlib/ndarray/vector/ctor' );
* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
* var gindexOfFalsy = require( '@stdlib/blas/ext/base/ndarray/gindex-of-falsy' );
*
* var x = vector( [ 1.0, 3.0, 0.0, 2.0 ], 'generic' );
*
* var v = gindexOfFalsy( [ x ] );
* var fromIndex = scalar2ndarray( 0, {
* 'dtype': 'generic'
* });
*
* var v = gindexOfFalsy( [ x, fromIndex ] );
* // returns 2
*/

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -20,10 +20,12 @@

// MODULES //

var ndarraylike2scalar = require( '@stdlib/ndarray/base/ndarraylike2scalar' );
var numelDimension = require( '@stdlib/ndarray/base/numel-dimension' );
var getStride = require( '@stdlib/ndarray/base/stride' );
var getOffset = require( '@stdlib/ndarray/base/offset' );
var getData = require( '@stdlib/ndarray/base/data-buffer' );
var clipIndex = require( '@stdlib/ndarray/base/clip-index' );
var strided = require( '@stdlib/blas/ext/base/gindex-of-falsy' ).ndarray;


Expand All @@ -37,21 +39,50 @@ var strided = require( '@stdlib/blas/ext/base/gindex-of-falsy' ).ndarray;
* - The function expects the following ndarrays:
*
* - a one-dimensional input ndarray.
* - a zero-dimensional ndarray containing the index from which to begin searching.
*
* @param {ArrayLikeObject<Object>} arrays - array-like object containing ndarrays
* @returns {integer} index
*
* @example
* var vector = require( '@stdlib/ndarray/vector/ctor' );
* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
*
* var x = vector( [ 1.0, 3.0, 0.0, 2.0 ], 'generic' );
*
* var v = gindexOfFalsy( [ x ] );
* var fromIndex = scalar2ndarray( 0, {
* 'dtype': 'generic'
* });
*
* var v = gindexOfFalsy( [ x, fromIndex ] );
* // returns 2
*/
function gindexOfFalsy( arrays ) {
var x = arrays[ 0 ];
return strided( numelDimension( x, 0 ), getData( x ), getStride( x, 0 ), getOffset( x ) ); // eslint-disable-line max-len
var fromIndex;
var stride;
var offset;
var idx;
var N;
var x;

x = arrays[ 0 ];
fromIndex = ndarraylike2scalar( arrays[ 1 ] );

N = numelDimension( x, 0 );
fromIndex = clipIndex( fromIndex, N );
if ( fromIndex >= N ) {
return -1;
}
N -= fromIndex;

stride = getStride( x, 0 );
offset = getOffset( x ) + ( stride*fromIndex );

idx = strided( N, getData( x ), stride, offset );
if ( idx >= 0 ) {
idx += fromIndex;
}
return idx;
}


Expand Down
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