dmsktrunc
Round each element in a double-precision floating-point strided array toward zero according to a strided mask array.
Usage
var dmsktrunc = require( '@stdlib/math/strided/special/dmsktrunc' );
dmsktrunc( N, x, sx, m, sm, y, sy )
Rounds each element in a double-precision floating-point strided array x toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array y.
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1 ] );
var y = new Float64Array( x.length );
dmsktrunc( x.length, x, 1, m, 1, y, 1 );
// y => <Float64Array>[ 1.0, 2.0, 0.0, 4.0, 0.0 ]
The function accepts the following arguments:
- N: number of indexed elements.
- x: input
Float64Array. - sx: index increment for
x. - m: mask
Uint8Array. - sm: index increment for
m. - y: output
Float64Array. - sy: index increment for
y.
The N and stride parameters determine which strided array elements 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,
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
dmsktrunc( 3, x, 2, m, 2, y, -1 );
// y => <Float64Array>[ 0.0, 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 views.
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
// Initial arrays...
var x0 = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m0 = new Uint8Array( [ 0, 0, 1, 0, 1, 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*1 ); // start at 2nd element
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element
dmsktrunc( 3, x1, -2, m1, -2, y1, 1 );
// y0 => <Float64Array>[ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0 ]
dmsktrunc.ndarray( N, x, sx, ox, m, sm, om, y, sy, oy )
Rounds each element in a double-precision floating-point strided array x toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array y using alternative indexing semantics.
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
dmsktrunc.ndarray( x.length, x, 1, 0, m, 1, 0, y, 1, 0 );
// y => <Float64Array>[ 1.0, 2.0, 0.0, 4.0, 0.0 ]
The function accepts the following additional arguments:
- ox: starting index for
x. - om: starting index for
m. - oy: starting index for
y.
While typed array views mandate a view offset based on the underlying buffer, the offset 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,
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
dmsktrunc.ndarray( 3, x, 2, 1, m, 2, 1, y, -1, y.length-1 );
// y => <Float64Array>[ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0 ]
Examples
var uniform = require( '@stdlib/random/base/uniform' );
var Float64Array = require( '@stdlib/array/float64' );
var Uint8Array = require( '@stdlib/array/uint8' );
var dmsktrunc = require( '@stdlib/math/strided/special/dmsktrunc' );
var x = new Float64Array( 10 );
var m = new Uint8Array( 10 );
var y = new Float64Array( 10 );
var i;
for ( i = 0; i < x.length; i++ ) {
x[ i ] = uniform( -10.0, 10.0 );
if ( uniform( 0.0, 1.0 ) < 0.5 ) {
m[ i ] = 1;
}
}
console.log( x );
console.log( m );
console.log( y );
dmsktrunc.ndarray( x.length, x, 1, 0, m, 1, 0, y, -1, y.length-1 );
console.log( y );
C APIs
Usage
#include "stdlib/math/strided/special/dmsktrunc.h"
stdlib_strided_dmsktrunc( N, *X, strideX, *Mask, strideMask, *Y, strideY )
Rounds each element in a double-precision floating-point strided array X toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array Y.
#include <stdint.h>
const double X[] = { 1.1, 2.5, -3.5, 4.0, -5.9, 6.4, -7.0, 8.2 };
const uint8_t Mask[] = { 0, 0, 1, 0, 1, 1, 0, 0 };
double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
const int64_t N = 4;
stdlib_strided_dmsktrunc( N, X, 2, Mask, 2, Y, 2 );
The function accepts the following arguments:
- N:
[in] int64_tnumber of indexed elements. - X:
[in] double*input array. - strideX:
[in] int64_tindex increment forX. - Mask:
[in] uint8_t*mask array. - strideMask:
[in] int64_tindex increment forMask. - Y:
[out] double*output array. - strideY:
[in] int64_tindex increment forY.
void stdlib_strided_dmsktrunc( 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 );
Examples
#include "stdlib/math/strided/special/dmsktrunc.h"
#include <stdint.h>
#include <stdio.h>
int main( void ) {
// Create an input strided array:
const double X[] = { 1.1, 2.5, -3.5, 4.0, -5.9, 6.4, -7.0, 8.2 };
// Create a mask strided array:
const uint8_t M[] = { 0, 0, 1, 0, 1, 1, 0, 0 };
// Create an output strided array:
double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
// Specify the number of elements:
const int64_t N = 4;
// Specify the stride lengths:
const int64_t strideX = 2;
const int64_t strideM = 2;
const int64_t strideY = 2;
// Compute the results:
stdlib_strided_dmsktrunc( N, X, strideX, M, strideM, Y, strideY );
// Print the results:
for ( int i = 0; i < 8; i++ ) {
printf( "Y[ %i ] = %lf\n", i, Y[ i ] );
}
}