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 | 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 39x 39x 39x 39x 39x 39x 39x 39x 39x 39x 8x 8x 31x 39x 8x 8x 39x 4x 4x 19x 19x 39x 8x 8x 39x 11x 11x 11x 19x 39x 2x 2x 2x 2x 2x | /**
* @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.
*/
'use strict';
// MODULES //
var isColumnMajor = require( '@stdlib/ndarray/base/assert/is-column-major-string' );
var resolveLayout = require( '@stdlib/blas/base/layout-resolve-str' );
var stride2offset = require( '@stdlib/strided/base/stride2offset' );
var max = require( '@stdlib/math/base/special/fast/max' );
var format = require( '@stdlib/string/format' );
var ndarray = require( './ndarray.js' );
// MAIN //
/**
* Generates a companion matrix.
*
* @param {(integer|string)} order - storage layout
* @param {NonNegativeInteger} N - number of indexed elements in `x`
* @param {Collection} x - input array containing polynomial coefficients
* @param {integer} strideX - stride length for `x`
* @param {Collection} out - output array
* @param {PositiveInteger} ldo - stride between successive contiguous vectors of the matrix `out` (a.k.a., leading dimension of the matrix `out`)
* @throws {TypeError} first argument must be a valid order
* @throws {RangeError} sixth argument must be a valid stride
* @returns {Collection} output matrix
*
* @example
* var x = [ 1.0, 2.0, 3.0 ];
* var out = [ 0.0, 0.0, 0.0, 0.0 ];
*
* gcompanion( 'row-major', 3, x, 1, out, 2 );
* // out => [ -2.0, -3.0, 1.0, 0.0 ]
*/
function gcompanion( order, N, x, strideX, out, ldo ) {
var iscm;
var sa1;
var sa2;
var ox;
var l;
var m;
l = resolveLayout( order );
if ( l === null ) {
throw new TypeError( format( 'invalid argument. First argument must be a valid order. Value: `%s`.', order ) );
}
m = N - 1;
if ( ldo < max( 1, m ) ) {
throw new RangeError( format( 'invalid argument. Sixth argument must be greater than or equal to max(1,%d). Value: `%d`.', m, ldo ) );
}
if ( N <= 1 ) {
return out;
}
ox = stride2offset( N, strideX );
iscm = isColumnMajor( l );
if ( iscm ) {
sa1 = 1;
sa2 = ldo;
} else { // order === 'row-major'
sa1 = ldo;
sa2 = 1;
}
return ndarray( N, x, strideX, ox, out, sa1, sa2, 0 );
}
// EXPORTS //
module.exports = gcompanion;
|