336 lines
10 KiB
Markdown
336 lines
10 KiB
Markdown
|
<!--
|
||
|
|
|
||
|
|
@license Apache-2.0
|
||
|
|
|
||
|
|
Copyright (c) 2020 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.
|
||
|
|
You may obtain a copy of the License at
|
||
|
|
|
||
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
|
||
|
|
Unless required by applicable law or agreed to in writing, software
|
||
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
See the License for the specific language governing permissions and
|
||
|
|
limitations under the License.
|
||
|
|
|
||
|
|
-->
|
||
|
|
|
||
|
|
<!-- lint disable maximum-heading-length -->
|
||
|
|
|
||
|
|
# dmskmap
|
||
|
|
|
||
|
|
> Apply a unary function accepting and returning double-precision floating-point numbers to each element in a double-precision floating-point strided input array according to a corresponding element in a strided mask array and assign each result to an element in a double-precision floating-point strided output array.
|
||
|
|
|
||
|
|
<section class="intro">
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.intro -->
|
||
|
|
|
||
|
|
<section class="usage">
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var dmskmap = require( '@stdlib/strided/base/dmskmap' );
|
||
|
|
```
|
||
|
|
|
||
|
|
#### dmskmap( N, x, strideX, mask, strideMask, y, strideY, fcn )
|
||
|
|
|
||
|
|
Applies a unary function accepting and returning double-precision floating-point numbers to each element in a double-precision floating-point strided input array according to a corresponding element in a strided mask array and assigns each result to an element in a double-precision floating-point strided output array.
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
||
|
|
|
||
|
|
var x = new Float64Array( [ -2.0, 1.0, -3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );
|
||
|
|
var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1, 1, 0 ] );
|
||
|
|
|
||
|
|
// Compute the absolute values in-place:
|
||
|
|
dmskmap( x.length, x, 1, m, 1, x, 1, abs );
|
||
|
|
// x => <Float64Array>[ 2.0, 1.0, -3.0, 5.0, 4.0, 0.0, -1.0, 3.0 ]
|
||
|
|
```
|
||
|
|
|
||
|
|
The function accepts the following arguments:
|
||
|
|
|
||
|
|
- **N**: number of indexed elements.
|
||
|
|
- **x**: input [`Float64Array`][@stdlib/array/float64].
|
||
|
|
- **strideX**: index increment for `x`.
|
||
|
|
- **mask**: mask [`Uint8Array`][@stdlib/array/uint8].
|
||
|
|
- **strideMask**: index increment for `mask`.
|
||
|
|
- **y**: output [`Float64Array`][@stdlib/array/float64].
|
||
|
|
- **strideY**: index increment for `y`.
|
||
|
|
- **fcn**: function to apply.
|
||
|
|
|
||
|
|
The `N` and `stride` parameters determine which elements in the strided arrays are accessed at runtime. For example, to index every other value in `x` and to index the first `N` elements of `y` in reverse order,
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var floor = require( '@stdlib/math/base/special/floor' );
|
||
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
||
|
|
|
||
|
|
var x = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );
|
||
|
|
var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );
|
||
|
|
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
|
||
|
|
|
||
|
|
var N = floor( x.length / 2 );
|
||
|
|
|
||
|
|
dmskmap( N, x, 2, m, 2, y, -1, abs );
|
||
|
|
// y => <Float64Array>[ 5.0, 0.0, 1.0, 0.0, 0.0, 0.0 ]
|
||
|
|
```
|
||
|
|
|
||
|
|
Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][@stdlib/array/float64] views.
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var floor = require( '@stdlib/math/base/special/floor' );
|
||
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
||
|
|
|
||
|
|
// Initial arrays...
|
||
|
|
var x0 = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );
|
||
|
|
var m0 = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );
|
||
|
|
var y0 = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
|
||
|
|
|
||
|
|
// Create offset views...
|
||
|
|
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
|
||
|
|
var m1 = new Uint8Array( m0.buffer, m0.BYTES_PER_ELEMENT*3 ); // start at 4th element
|
||
|
|
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element
|
||
|
|
|
||
|
|
var N = floor( x0.length / 2 );
|
||
|
|
|
||
|
|
dmskmap( N, x1, -2, m1, 1, y1, 1, abs );
|
||
|
|
// y0 => <Float64Array>[ 0.0, 0.0, 0.0, 6.0, 4.0, 0.0 ]
|
||
|
|
```
|
||
|
|
|
||
|
|
#### dmskmap.ndarray( N, x, strideX, offsetX, mask, strideMask, offsetMask, y, strideY, offsetY, fcn )
|
||
|
|
|
||
|
|
Applies a unary function accepting and returning double-precision floating-point numbers to each element in a double-precision floating-point strided input array according to a corresponding element in a strided mask array and assigns each result to an element in a double-precision floating-point strided output array using alternative indexing semantics.
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
||
|
|
|
||
|
|
var x = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0 ] );
|
||
|
|
var m = new Uint8Array( [ 0, 0, 1, 0, 0 ] );
|
||
|
|
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
|
||
|
|
|
||
|
|
dmskmap.ndarray( x.length, x, 1, 0, m, 1, 0, y, 1, 0, abs );
|
||
|
|
// y => <Float64Array>[ 1.0, 2.0, 0.0, 4.0, 5.0 ]
|
||
|
|
```
|
||
|
|
|
||
|
|
The function accepts the following additional arguments:
|
||
|
|
|
||
|
|
- **offsetX**: starting index for `x`.
|
||
|
|
- **offsetMask**: starting index for `mask`.
|
||
|
|
- **offsetY**: starting index for `y`.
|
||
|
|
|
||
|
|
While [`typed array`][@stdlib/array/float64] views mandate a view offset based on the underlying `buffer`, the `offsetX` and `offsetY` parameters support indexing semantics based on starting indices. For example, to index every other value in `x` starting from the second value and to index the last `N` elements in `y`,
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var floor = require( '@stdlib/math/base/special/floor' );
|
||
|
|
var abs = require( '@stdlib/math/base/special/abs' );
|
||
|
|
|
||
|
|
var x = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );
|
||
|
|
var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );
|
||
|
|
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
|
||
|
|
|
||
|
|
var N = floor( x.length / 2 );
|
||
|
|
|
||
|
|
dmskmap.ndarray( N, x, 2, 1, m, 2, 1, y, -1, y.length-1, abs );
|
||
|
|
// y => <Float64Array>[ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0 ]
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.usage -->
|
||
|
|
|
||
|
|
<section class="notes">
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.notes -->
|
||
|
|
|
||
|
|
<section class="examples">
|
||
|
|
|
||
|
|
## Examples
|
||
|
|
|
||
|
|
<!-- eslint no-undef: "error" -->
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var round = require( '@stdlib/math/base/special/round' );
|
||
|
|
var randu = require( '@stdlib/random/base/randu' );
|
||
|
|
var bernoulli = require( '@stdlib/random/base/bernoulli' );
|
||
|
|
var Float64Array = require( '@stdlib/array/float64' );
|
||
|
|
var Uint8Array = require( '@stdlib/array/uint8' );
|
||
|
|
var dmskmap = require( '@stdlib/strided/base/dmskmap' );
|
||
|
|
|
||
|
|
function scale( x ) {
|
||
|
|
return x * 10.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
var x = new Float64Array( 10 );
|
||
|
|
var m = new Uint8Array( x.length );
|
||
|
|
var y = new Float64Array( x.length );
|
||
|
|
|
||
|
|
var i;
|
||
|
|
for ( i = 0; i < x.length; i++ ) {
|
||
|
|
x[ i ] = round( (randu()*200.0) - 100.0 );
|
||
|
|
m[ i ] = bernoulli( 0.2 );
|
||
|
|
}
|
||
|
|
console.log( x );
|
||
|
|
console.log( m );
|
||
|
|
console.log( y );
|
||
|
|
|
||
|
|
dmskmap.ndarray( x.length, x, 1, 0, m, 1, 0, y, -1, y.length-1, scale );
|
||
|
|
console.log( y );
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.examples -->
|
||
|
|
|
||
|
|
<!-- C interface documentation. -->
|
||
|
|
|
||
|
|
* * *
|
||
|
|
|
||
|
|
<section class="c">
|
||
|
|
|
||
|
|
## C APIs
|
||
|
|
|
||
|
|
<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
|
||
|
|
|
||
|
|
<section class="intro">
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.intro -->
|
||
|
|
|
||
|
|
<!-- C usage documentation. -->
|
||
|
|
|
||
|
|
<section class="usage">
|
||
|
|
|
||
|
|
### Usage
|
||
|
|
|
||
|
|
```c
|
||
|
|
#include "stdlib/strided/base/dmskmap.h"
|
||
|
|
```
|
||
|
|
|
||
|
|
#### stdlib_strided_dmskmap( N, \*X, strideX, \*Mask, strideMask, \*Y, strideY, fcn )
|
||
|
|
|
||
|
|
Applies a unary function accepting and returning double-precision floating-point numbers to each element in a double-precision floating-point strided input array according to a corresponding element in a strided mask array and assigns each result to an element in a double-precision floating-point strided output array.
|
||
|
|
|
||
|
|
```c
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
static double scale( const double x ) {
|
||
|
|
return x * 10.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
double X[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
|
||
|
|
uint8_t M[] = { 0, 0, 1, 0, 0, 1 };
|
||
|
|
double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
|
||
|
|
|
||
|
|
int64_t N = 6;
|
||
|
|
|
||
|
|
stdlib_strided_dmskmap( N, X, 1, M, 1, Y, 1, scale );
|
||
|
|
```
|
||
|
|
|
||
|
|
The function accepts the following arguments:
|
||
|
|
|
||
|
|
- **N**: `[in] int64_t` number of indexed elements.
|
||
|
|
- **X**: `[in] double*` input array.
|
||
|
|
- **strideX** `[in] int64_t` index increment for `X`.
|
||
|
|
- **Mask**: `[in] uint8_t*` mask array.
|
||
|
|
- **strideMask**: `[in] int64_t` index increment for `Mask`.
|
||
|
|
- **Y**: `[out] double*` output array.
|
||
|
|
- **strideY**: `[in] int64_t` index increment for `Y`.
|
||
|
|
- **fcn**: `[in] double (*fcn)( double )` unary function to apply.
|
||
|
|
|
||
|
|
```c
|
||
|
|
void stdlib_strided_dmskmap( const int64_t N, const double *X, const int64_t strideX, const uint8_t *Mask, const int64_t strideMask, double *Y, const int64_t strideY, double (*fcn)( double ) );
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.usage -->
|
||
|
|
|
||
|
|
<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
|
||
|
|
|
||
|
|
<section class="notes">
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.notes -->
|
||
|
|
|
||
|
|
<!-- C API usage examples. -->
|
||
|
|
|
||
|
|
<section class="examples">
|
||
|
|
|
||
|
|
### Examples
|
||
|
|
|
||
|
|
```c
|
||
|
|
#include "stdlib/strided/base/dmskmap.h"
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <inttypes.h>
|
||
|
|
|
||
|
|
// Define a callback:
|
||
|
|
static double scale( const double x ) {
|
||
|
|
return x * 10.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int main() {
|
||
|
|
// Create an input strided array:
|
||
|
|
double X[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
|
||
|
|
|
||
|
|
// Create a mask strided array:
|
||
|
|
uint8_t M[] = { 0, 0, 1, 0, 0, 1 };
|
||
|
|
|
||
|
|
// Create an output strided array:
|
||
|
|
double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
|
||
|
|
|
||
|
|
// Specify the number of elements:
|
||
|
|
int64_t N = 6;
|
||
|
|
|
||
|
|
// Define the strides:
|
||
|
|
int64_t strideX = 1;
|
||
|
|
int64_t strideM = 1;
|
||
|
|
int64_t strideY = -1;
|
||
|
|
|
||
|
|
// Apply the callback:
|
||
|
|
stdlib_strided_dmskmap( N, X, strideX, M, strideM, Y, strideY, scale );
|
||
|
|
|
||
|
|
// Print the results:
|
||
|
|
for ( int64_t i = 0; i < N; i++ ) {
|
||
|
|
printf( "Y[ %"PRId64" ] = %lf\n", i, Y[ i ] );
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.examples -->
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.c -->
|
||
|
|
|
||
|
|
<section class="links">
|
||
|
|
|
||
|
|
[@stdlib/array/float64]: https://www.npmjs.com/package/@stdlib/array-float64
|
||
|
|
|
||
|
|
[@stdlib/array/uint8]: https://www.npmjs.com/package/@stdlib/array-uint8
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
<!-- /.links -->
|