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Merged
merged 12 commits into from
Feb 16, 2025
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feat: add C ndarray implementation for blas/base/zscal #4864

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73cec23
feat: add C ndarray implementation for zscal
aman-095 Jan 23, 2025
fab60bb
refactor: revert implementation for ndarray
aman-095 Jan 28, 2025
517a2be
test: remove duplicate tests
aman-095 Jan 28, 2025
656fc60
Merge branch 'stdlib-js:develop' into zscal-ndarray
aman-095 Feb 11, 2025
91f9d28
chore: update description
aman-095 Feb 11, 2025
7e20875
Merge remote-tracking branch 'upstream/develop' into zscal-ndarray
stdlib-bot Feb 14, 2025
c06accf
chore: resolve lint error
aman-095 Feb 14, 2025
f1a23e5
Merge branch 'develop' into zscal-ndarray
kgryte Feb 16, 2025
0191794
docs: fix note
kgryte Feb 16, 2025
96ce8ee
docs: update copy
kgryte Feb 16, 2025
3222785
docs: update note
kgryte Feb 16, 2025
6013447
docs: fix example
kgryte Feb 16, 2025
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137 changes: 85 additions & 52 deletions lib/node_modules/@stdlib/blas/base/zscal/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

@license Apache-2.0

Copyright (c) 2024 The Stdlib Authors.
Copyright (c) 2025 The Stdlib Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -30,39 +30,39 @@ limitations under the License.
var zscal = require( '@stdlib/blas/base/zscal' );
```

#### zscal( N, za, zx, strideX )
#### zscal( N, alpha, x, strideX )

Scales values from `zx` by `za`.
Scales values from `x` by `alpha`.

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var zx = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var za = new Complex128( 2.0, 0.0 );
var x = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
var alpha = new Complex128( 2.0, 0.0 );

zscal( 3, za, zx, 1 );
// zx => <Complex128Array>[ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ]
zscal( 3, alpha, x, 1 );
// x => <Complex128Array>[ 2.0, 2.0, 2.0, 2.0, 2.0, 2.0 ]
```

The function has the following parameters:

- **N**: number of indexed elements.
- **za**: scalar [`Complex128`][@stdlib/complex/float64/ctor] constant.
- **zx**: input [`Complex128Array`][@stdlib/array/complex128].
- **strideX**: index increment for `zx`.
- **alpha**: scalar [`Complex128`][@stdlib/complex/float64/ctor] constant.
- **x**: input [`Complex128Array`][@stdlib/array/complex128].
- **strideX**: index increment for `x`.

The `N` and stride parameters determine how values from `zx` are scaled by `za`. For example, to scale every other value in `zx` by `za`,
The `N` and stride parameters determine how values from `x` are scaled by `alpha`. For example, to scale every other value in `x` by `alpha`,

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var za = new Complex128( 2.0, 0.0 );
var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var alpha = new Complex128( 2.0, 0.0 );

zscal( 2, za, zx, 2 );
// zx => <Complex128Array>[ 2.0, 4.0, 3.0, 4.0, 10.0, 12.0, 7.0, 8.0 ]
zscal( 2, alpha, x, 2 );
// x => <Complex128Array>[ 2.0, 4.0, 3.0, 4.0, 10.0, 12.0, 7.0, 8.0 ]
```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
Expand All @@ -74,49 +74,49 @@ var Complex128Array = require( '@stdlib/array/complex128' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );

// Initial array:
var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var x0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

// Define a scalar constant:
var za = new Complex128( 2.0, 2.0 );
var alpha = new Complex128( 2.0, 2.0 );

// Create an offset view:
var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var x1 = new Complex128Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Scales every other value from `zx1` by `za`...
zscal( 3, za, zx1, 1 );
// zx0 => <Complex128Array>[ 1.0, 2.0, -2.0, 14.0, -2.0, 22.0, -2.0, 30.0 ]
zscal( 3, alpha, x1, 1 );
// x0 => <Complex128Array>[ 1.0, 2.0, -2.0, 14.0, -2.0, 22.0, -2.0, 30.0 ]
```

#### zscal.ndarray( N, za, zx, strideX, offsetX )
#### zscal.ndarray( N, alpha, x, strideX, offsetX )

Scales values from `zx` by `za` using alternative indexing semantics.
Scales values from `x` by `alpha` using alternative indexing semantics.

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var za = new Complex128( 2.0, 2.0 );
var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var alpha = new Complex128( 2.0, 2.0 );

zscal.ndarray( 3, za, zx, 1, 0 );
// zx => <Complex128Array>[ -2.0, 6.0, -2.0, 14.0, -2.0, 22.0 ]
zscal.ndarray( 3, alpha, x, 1, 0 );
// x => <Complex128Array>[ -2.0, 6.0, -2.0, 14.0, -2.0, 22.0 ]
```

The function has the following additional parameters:

- **offsetX**: starting index for `zx`.
- **offsetX**: starting index for `x`.

While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to scale every other value in the input strided array starting from the second element,

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var za = new Complex128( 2.0, 2.0 );
var x = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var alpha = new Complex128( 2.0, 2.0 );

zscal.ndarray( 2, za, zx, 2, 1 );
// zx => <Complex128Array>[ 1.0, 2.0, -2.0, 14.0, 5.0, 6.0, -2.0, 30.0 ]
zscal.ndarray( 2, alpha, x, 2, 1 );
// x => <Complex128Array>[ 1.0, 2.0, -2.0, 14.0, 5.0, 6.0, -2.0, 30.0 ]
```

</section>
Expand All @@ -127,7 +127,7 @@ zscal.ndarray( 2, za, zx, 2, 1 );

## Notes

- If `N <= 0` or `strideX <= 0` , both functions return `zx` unchanged.
- If `N <= 0` or `strideX <= 0` , both functions return `x` unchanged.
- `zscal()` corresponds to the [BLAS][blas] level 1 function [`zscal`][zscal].

</section>
Expand All @@ -150,15 +150,15 @@ function rand() {
return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}

var zx = filledarrayBy( 10, 'complex128', rand );
console.log( zx.toString() );
var x = filledarrayBy( 10, 'complex128', rand );
console.log( x.toString() );

var za = new Complex128( 2.0, 2.0 );
console.log( za.toString() );
var alpha = new Complex128( 2.0, 2.0 );
console.log( alpha.toString() );

// Scales elements from `zx` by `za`:
zscal( zx.length, za, zx, 1 );
console.log( zx.get( zx.length-1 ).toString() );
// Scales elements from `x` by `alpha`:
zscal( x.length, alpha, x, 1 );
console.log( x.get( x.length-1 ).toString() );
```

</section>
Expand Down Expand Up @@ -191,28 +191,53 @@ console.log( zx.get( zx.length-1 ).toString() );
#include "stdlib/blas/base/zscal.h"
```

#### c_zscal( N, za, \*ZX, strideX )
#### c_zscal( N, alpha, \*X, strideX )

Scales values from `ZX` by `za`.
Scales values from `X` by `alpha`.

```c
#include "stdlib/complex/float64/ctor.h"

double zx[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
const stdlib_complex128_t za = stdlib_complex128( 2.0, 2.0 );
double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
const stdlib_complex128_t alpha = stdlib_complex128( 2.0, 2.0 );

c_zscal( 4, za, (void *)zx, 1 );
c_zscal( 4, alpha, (void *)x, 1 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **za**: `[in] stdlib_complex128_t` scalar constant.
- **ZX**: `[inout] void*` input array.
- **strideX**: `[in] CBLAS_INT` index increment for `ZX`.
- **alpha**: `[in] stdlib_complex128_t` scalar constant.
- **X**: `[inout] void*` input array.
- **strideX**: `[in] CBLAS_INT` index increment for `X`.

```c
void c_zscal( const CBLAS_INT N, const stdlib_complex128_t za, void *ZX, const CBLAS_INT strideX );
void c_zscal( const CBLAS_INT N, const stdlib_complex128_t alpha, void *X, const CBLAS_INT strideX );
```

#### c_zscal_ndarray( N, alpha, \*X, strideX, offsetX )

Scales values from `X` by `alpha` using alternative indexing semantics.

```c
#include "stdlib/complex/float64/ctor.h"

double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
const stdlib_complex128_t alpha = stdlib_complex128( 2.0, 2.0 );

c_zscal_ndarray( 4, alpha, (void *)x, 1, 0 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **alpha**: `[in] stdlib_complex128_t` scalar constant.
- **X**: `[inout] void*` input array.
- **strideX**: `[in] CBLAS_INT` index increment for `X`.
- **offsetX**: `[in] CBLAS_INT` starting index for `X`.

```c
void c_zscal_ndarray( const CBLAS_INT N, const stdlib_complex128_t alpha, void *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );
```

</section>
Expand Down Expand Up @@ -240,10 +265,10 @@ void c_zscal( const CBLAS_INT N, const stdlib_complex128_t za, void *ZX, const C

int main( void ) {
// Create a strided array of interleaved real and imaginary components:
double zx[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };

// Create a complex scalar:
const stdlib_complex128_t ca = stdlib_complex128( 2.0, 2.0 );
const stdlib_complex128_t alpha = stdlib_complex128( 2.0, 2.0 );

// Specify the number of elements:
const int N = 4;
Expand All @@ -252,11 +277,19 @@ int main( void ) {
const int strideX = 1;

// Scale the elements of the array:
c_zscal( N, za, (void *)zx, strideX );
c_zscal( N, alpha, (void *)x, strideX );

// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "x[ %i ] = %lf + %lfj\n", i, x[ i*2 ], x[ (i*2)+1 ] );
}

// Scale the elements of the array using alternative indexing semantics:
c_zscal_ndarray( N, alpha, (void *)x, -strideX, N-1 );

// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "zx[ %i ] = %f + %fj\n", i, zx[ i*2 ], zx[ (i*2)+1 ] );
printf( "x[ %i ] = %lf + %lfj\n", i, x[ i*2 ], x[ (i*2)+1 ] );
}
}
```
Expand Down
47 changes: 44 additions & 3 deletions lib/node_modules/@stdlib/blas/base/zscal/benchmark/c/benchmark.length.c
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
/**
* @license Apache-2.0
*
* Copyright (c) 2024 The Stdlib Authors.
* Copyright (c) 2025 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down Expand Up @@ -95,7 +95,7 @@ static double rand_double( void ) {
* @param len array length
* @return elapsed time in seconds
*/
static double benchmark( int iterations, int len ) {
static double benchmark1( int iterations, int len ) {
stdlib_complex128_t za;
double zx[ len*2 ];
double elapsed;
Expand All @@ -122,6 +122,40 @@ static double benchmark( int iterations, int len ) {
return elapsed;
}

/**
* Runs a benchmark.
*
* @param iterations number of iterations
* @param len array length
* @return elapsed time in seconds
*/
static double benchmark2( int iterations, int len ) {
stdlib_complex128_t za;
double zx[ len*2 ];
double elapsed;
double t;
int i;

za = stdlib_complex128( 1.0, 0.0 );
for ( i = 0; i < len*2; i+=2 ) {
zx[ i ] = ( rand_double()*2.0 ) - 1.0;
zx[ i+1 ] = ( rand_double()*2.0 ) - 1.0;
}
t = tic();
for ( i = 0; i < iterations; i++ ) {
c_zscal_ndarray( len, za, (void *)zx, 1, 0 );
if ( zx[ 0 ] != zx[ 0 ] ) {
printf( "should not return NaN\n" );
break;
}
}
elapsed = tic() - t;
if ( zx[ 0 ] != zx[ 0 ] ) {
printf( "should not return NaN\n" );
}
return elapsed;
}

/**
* Main execution sequence.
*/
Expand All @@ -144,7 +178,14 @@ int main( void ) {
for ( j = 0; j < REPEATS; j++ ) {
count += 1;
printf( "# c::%s:len=%d\n", NAME, len );
elapsed = benchmark( iter, len );
elapsed = benchmark1( iter, len );
print_results( iter, elapsed );
printf( "ok %d benchmark finished\n", count );
}
for ( j = 0; j < REPEATS; j++ ) {
count += 1;
printf( "# c::%s:ndarray:len=%d\n", NAME, len );
elapsed = benchmark2( iter, len );
print_results( iter, elapsed );
printf( "ok %d benchmark finished\n", count );
}
Expand Down
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