Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 34x 34x 34x 34x 34x 34x 34x 34x 4x 4x 30x 30x 34x 93x 93x 93x 34x 18x 18x 55x 55x 33x 33x 22x 22x 22x 22x 55x 54x 54x 21x 21x 33x 33x 33x 33x 33x 33x 33x 33x 33x 54x 1x 1x 54x 55x 34x 12x 12x 38x 38x 26x 26x 12x 12x 12x 38x 26x 26x 26x 26x 26x 26x 26x 38x 12x 30x 34x 3x 3x 3x 3x 3x | /**
* @license Apache-2.0
*
* Copyright (c) 2026 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.
*/
/* eslint-disable max-len */
'use strict';
// MODULES //
var dswap = require( '@stdlib/blas/base/dswap' ).ndarray;
// MAIN //
/**
* Rearranges the rows of an `M` by `N` matrix `X` as specified by a permutation vector `K`.
*
* @private
* @param {boolean} forwrd - boolean indicating whether to apply a forward permutation
* @param {NonNegativeInteger} M - number of rows of `X`
* @param {NonNegativeInteger} N - number of columns of `X`
* @param {Float64Array} X - input matrix
* @param {integer} strideX1 - stride of the first dimension of `X`
* @param {integer} strideX2 - stride of the second dimension of `X`
* @param {NonNegativeInteger} offsetX - starting index for `X`
* @param {Int32Array} K - permutation vector
* @param {integer} strideK - stride length of `K`
* @param {NonNegativeInteger} offsetK - starting index for `K`
* @returns {Float64Array} permuted matrix `X`
*
* @example
* var Int32Array = require( '@stdlib/array/int32' );
* var Float64Array = require( '@stdlib/array/float64' );
*
* var X = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); // => [ [ 1.0, 2.0 ], [ 3.0, 4.0 ], [ 5.0, 6.0 ] ]
* var K = new Int32Array( [ 2, 0, 1 ] );
*
* dlapmr( true, 3, 2, X, 2, 1, 0, K, 1, 0 );
* // X => <Float64Array>[ 5.0, 6.0, 1.0, 2.0, 3.0, 4.0 ]
*/
function dlapmr( forwrd, M, N, X, strideX1, strideX2, offsetX, K, strideK, offsetK ) {
var temp;
var ik;
var ii;
var j;
var i;
if ( M <= 1 ) {
return X;
}
// Negate all entries of K to mark them as unprocessed...
ik = offsetK;
for ( i = 0; i < M; i++ ) {
K[ ik ] = -K[ ik ] - 1;
ik += strideK;
}
if ( forwrd ) {
// Forward permutation...
for ( i = 0; i < M; i++ ) {
ik = offsetK + ( i * strideK );
if ( K[ ik ] >= 0 ) {
continue;
}
j = i;
K[ ik ] = -K[ ik ] - 1;
ii = K[ ik ]; // `ii` is the source row index
while ( true ) {
ik = offsetK + ( ii * strideK );
if ( K[ ik ] >= 0 ) {
break;
}
// Swap row `j` and row `ii`...
dswap( N, X, strideX2, offsetX + ( j * strideX1 ), X, strideX2, offsetX + ( ii * strideX1 ) );
K[ ik ] = -K[ ik ] - 1;
temp = j;
j = ii;
ii = K[ ik ];
// Prevent infinite loop for identity permutations:
if ( ii === temp ) {
break;
}
}
}
} else {
// Backward permutation...
for ( i = 0; i < M; i++ ) {
ik = offsetK + ( i * strideK );
if ( K[ ik ] >= 0 ) {
continue;
}
K[ ik ] = -K[ ik ] - 1;
j = K[ ik ];
while ( j !== i ) {
// Swap row `i` and row `j`...
dswap( N, X, strideX2, offsetX + ( i * strideX1 ), X, strideX2, offsetX + ( j * strideX1 ) );
ik = offsetK + ( j * strideK );
K[ ik ] = -K[ ik ] - 1;
j = K[ ik ];
}
}
}
return X;
}
// EXPORTS //
module.exports = dlapmr;
|