126 lines
2.6 KiB
JavaScript
126 lines
2.6 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2020 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var Float32Array = require( '@stdlib/array/float32' );
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// MAIN //
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/**
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* Interchanges two complex single-precision floating-point vectors.
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*
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* @param {PositiveInteger} N - number of values to swap
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* @param {Complex64Array} x - first input array
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* @param {integer} strideX - `x` stride length
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* @param {Complex64Array} y - second input array
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* @param {integer} strideY - `y` stride length
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* @returns {Complex64Array} `y`
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*
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* @example
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* var Complex64Array = require( '@stdlib/array/complex64' );
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* var real = require( '@stdlib/complex/real' );
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* var imag = require( '@stdlib/complex/imag' );
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*
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* var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
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* var y = new Complex64Array( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
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*
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* cswap( x.length, x, 1, y, 1 );
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*
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* var z = y.get( 0 );
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* // returns <Complex64>
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*
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* var re = real( z );
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* // returns 1.0
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*
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* var im = imag( z );
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* // returns 2.0
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*
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* z = x.get( 0 );
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* // returns <Complex64>
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*
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* re = real( z );
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* // returns 7.0
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*
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* im = imag( z );
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* // returns 8.0
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*/
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function cswap( N, x, strideX, y, strideY ) {
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var viewX;
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var viewY;
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var tmp;
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var sx;
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var sy;
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var ix;
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var iy;
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var i;
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var j;
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if ( N <= 0 ) {
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return y;
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}
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viewX = new Float32Array( x.buffer, x.byteOffset, x.length*2 );
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viewY = new Float32Array( y.buffer, y.byteOffset, y.length*2 );
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if ( strideX === 1 && strideY === 1 ) {
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for ( i = 0; i < N*2; i += 2 ) {
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tmp = viewX[ i ];
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viewX[ i ] = viewY[ i ];
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viewY[ i ] = tmp;
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j = i + 1;
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tmp = viewX[ j ];
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viewX[ j ] = viewY[ j ];
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viewY[ j ] = tmp;
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}
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return y;
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}
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if ( strideX < 0 ) {
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ix = 2 * (1-N) * strideX;
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} else {
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ix = 0;
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}
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if ( strideY < 0 ) {
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iy = 2 * (1-N) * strideY;
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} else {
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iy = 0;
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}
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sx = strideX * 2;
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sy = strideY * 2;
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for ( i = 0; i < N; i++ ) {
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tmp = viewX[ ix ];
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viewX[ ix ] = viewY[ iy ];
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viewY[ iy ] = tmp;
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tmp = viewX[ ix+1 ];
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viewX[ ix+1 ] = viewY[ iy+1 ];
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viewY[ iy+1 ] = tmp;
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ix += sx;
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iy += sy;
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}
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return y;
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}
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// EXPORTS //
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module.exports = cswap;
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