@stdlib/blas-ext-base-gsort2ins
Version:
Simultaneously sort two strided arrays based on the sort order of the first array using insertion sort.
206 lines (183 loc) • 5.79 kB
JavaScript
/**
* @license Apache-2.0
*
* 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.
* 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.
*/
;
// MODULES //
var isNegativeZero = require( '@stdlib/math-base-assert-is-negative-zero' );
var isnan = require( '@stdlib/math-base-assert-is-nan' );
// MAIN //
/**
* Simultaneously sorts two strided arrays based on the sort order of the first array using insertion sort.
*
* @private
* @param {PositiveInteger} N - number of indexed elements
* @param {number} order - sort order
* @param {Object} x - first input array object
* @param {Collection} x.data - first input array data
* @param {Array<Function>} x.accessors - first input array element accessors
* @param {integer} strideX - stride length for `x`
* @param {NonNegativeInteger} offsetX - starting index for `x`
* @param {Object} y - second input array object
* @param {Collection} y.data - second input array data
* @param {Array<Function>} y.accessors - second input array element accessors
* @param {integer} strideY - stride length for `y`
* @param {NonNegativeInteger} offsetY - starting index for `y`
* @returns {Object} `x`
*
* @example
* var toAccessorArray = require( '@stdlib/array-base-to-accessor-array' );
* var arraylike2object = require( '@stdlib/array-base-arraylike2object' );
*
* var x = [ 1.0, -2.0, 3.0, -4.0 ];
* var y = [ 0.0, 1.0, 2.0, 3.0 ];
*
* gsort2ins( x.length, 1.0, arraylike2object( toAccessorArray( x ) ), 1, 0, arraylike2object( toAccessorArray( y ) ), 1, 0 );
*
* console.log( x );
* // => [ -4.0, -2.0, 1.0, 3.0 ]
*
* console.log( y );
* // => [ 3.0, 1.0, 0.0, 2.0 ]
*/
function gsort2ins( N, order, x, strideX, offsetX, y, strideY, offsetY ) {
var xbuf;
var ybuf;
var xget;
var yget;
var xset;
var yset;
var flg;
var ix;
var jx;
var fx;
var lx;
var iy;
var jy;
var fy;
var ly;
var vx;
var vy;
var ux;
var i;
// Cache reference to array data:
xbuf = x.data;
ybuf = y.data;
// Cache reference to the element accessors:
xget = x.accessors[ 0 ];
xset = x.accessors[ 1 ];
yget = y.accessors[ 0 ];
yset = y.accessors[ 1 ];
// For a positive stride, sorting in decreasing order is equivalent to providing a negative stride and sorting in increasing order, and, for a negative stride, sorting in decreasing order is equivalent to providing a positive stride and sorting in increasing order...
if ( order < 0.0 ) {
strideX *= -1;
strideY *= -1;
offsetX -= (N-1) * strideX;
offsetY -= (N-1) * strideY;
}
fx = offsetX; // first index
lx = fx + ((N-1)*strideX); // last index
ix = fx + strideX;
fy = offsetY; // first index
ly = fy + ((N-1)*strideY); // last index
iy = fy + strideY;
if ( strideX < 0 ) {
// Traverse the strided array from right-to-left...
// Sort in increasing order...
for ( i = 1; i < N; i++ ) {
vx = xget( xbuf, ix );
vy = yget( ybuf, iy );
// Sort `NaN` values to the end (i.e., the left)...
if ( isnan( vx ) ) {
jx = ix;
jy = iy;
// Shift all values (including NaNs) to the left of the current element to the right...
while ( jx > lx ) {
xset( xbuf, jx, xget( xbuf, jx+strideX ) );
yset( ybuf, jy, yget( ybuf, jy+strideY ) );
jx += strideX;
jy += strideY;
}
xset( xbuf, lx, vx );
yset( ybuf, ly, vy );
} else {
flg = isNegativeZero( vx );
jx = ix - strideX;
jy = iy - strideY;
// Shift all larger values to the right of the current element to the left...
while ( jx <= fx ) {
ux = xget( xbuf, jx );
if ( ux <= vx && !(flg && ux === vx && isNegativeZero( ux ) === false) ) { // eslint-disable-line max-len
// Note: positive zeros (and NaNs (e.g., when last element is NaN)) are sorted to the left
break;
}
xset( xbuf, jx+strideX, ux );
yset( ybuf, jy+strideY, yget( ybuf, jy ) );
jx -= strideX;
jy -= strideY;
}
xset( xbuf, jx+strideX, vx );
yset( ybuf, jy+strideY, vy );
ix += strideX;
iy += strideY;
}
}
return x;
}
// Traverse the strided array from left-to-right...
// Sort in increasing order...
for ( i = 1; i < N; i++ ) {
vx = xget( xbuf, ix );
vy = yget( ybuf, iy );
// Sort `NaN` values to the end...
if ( isnan( vx ) ) {
jx = ix;
jy = iy;
// Shift all values (including NaNs) to the right of the current element to the left...
while ( jx < lx ) {
xset( xbuf, jx, xget( xbuf, jx+strideX ) );
yset( ybuf, jy, yget( ybuf, jy+strideY ) );
jx += strideX;
jy += strideY;
}
xset( xbuf, lx, vx );
yset( ybuf, ly, vy );
} else {
flg = isNegativeZero( vx );
jx = ix - strideX;
jy = iy - strideY;
// Shift all larger values to the left of the current element to the right...
while ( jx >= fx ) {
ux = xget( xbuf, jx );
if ( ux <= vx && !(flg && ux === vx && isNegativeZero( ux ) === false) ) { // eslint-disable-line max-len
// Note: positive zeros (and NaNs (e.g., when first element is NaN)) are sorted to the right
break;
}
xset( xbuf, jx+strideX, ux );
yset( ybuf, jy+strideY, yget( ybuf, jy ) );
jx -= strideX;
jy -= strideY;
}
xset( xbuf, jx+strideX, vx );
yset( ybuf, jy+strideY, vy );
ix += strideX;
iy += strideY;
}
}
return x;
}
// EXPORTS //
module.exports = gsort2ins;