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| 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 | 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 2x 2x 2x 2x 2x 2x 2x 24x 24x 6x 6x 24x 3x 3x 15x 24x 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 format = require( '@stdlib/string/format' );
var base = require( './base.js' );
// MAIN //
/**
* Solves a system of equations with a tridiagonal matrix `T` following a precomputed factorization of `T - lambda*I`.
*
* @param {integer} job - specifies the job to be performed
* @param {NonNegativeInteger} N - order of the matrix `T`
* @param {Float64Array} A - diagonal elements of `U`
* @param {Float64Array} B - first super-diagonal elements of `U`
* @param {Float64Array} C - sub-diagonal elements of `L`
* @param {Float64Array} D - second super-diagonal elements of `U`
* @param {Int32Array} IN - details of the matrix `P`
* @param {Float64Array} Y - right-hand side vector which is overwritten by the solution vector
* @param {Float64Array} TOL - tolerance used to perturb very small diagonal elements when `job` is negative
* @throws {RangeError} first argument must be `1`, `-1`, `2`, or `-2`
* @throws {RangeError} second argument must be a nonnegative integer
* @returns {integer} status code
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
* var Int32Array = require( '@stdlib/array/int32' );
*
* var A = new Float64Array( [ 4.0, 3.75, 3.7333333333333334 ] );
* var B = new Float64Array( [ 1.0, 1.0 ] );
* var C = new Float64Array( [ 0.25, 0.26666666666666666 ] );
* var D = new Float64Array( [ 0.0 ] );
* var IN = new Int32Array( [ 0, 0, 0 ] );
* var Y = new Float64Array( [ 1.0, 2.0, 3.0 ] );
* var TOL = new Float64Array( [ 0.0 ] );
*
* dlagts( 1, 3, A, B, C, D, IN, Y, TOL );
* // Y => <Float64Array>[ ~0.179, ~0.286, ~0.679 ]
*/
function dlagts( job, N, A, B, C, D, IN, Y, TOL ) {
if ( job !== 1 && job !== -1 && job !== 2 && job !== -2 ) {
throw new RangeError( format( 'invalid argument. First argument must be one of the following: `1`, `-1`, `2`, or `-2`. Value: `%d`.', job ) );
}
if ( N < 0 ) {
throw new RangeError( format( 'invalid argument. Second argument must be a nonnegative integer. Value: `%d`.', N ) );
}
return base( job, N, A, 1, 0, B, 1, 0, C, 1, 0, D, 1, 0, IN, 1, 0, Y, 1, 0, TOL, 0 );
}
// EXPORTS //
module.exports = dlagts;
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