jiangchengfeiyi-xiaochengxu/node_modules/mathjs/lib/cjs/function/algebra/decomposition/slu.js
2025-01-02 11:13:50 +08:00

107 lines
3.6 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.createSlu = void 0;
var _number = require("../../../utils/number.js");
var _factory = require("../../../utils/factory.js");
var _csSqr = require("../sparse/csSqr.js");
var _csLu = require("../sparse/csLu.js");
const name = 'slu';
const dependencies = ['typed', 'abs', 'add', 'multiply', 'transpose', 'divideScalar', 'subtract', 'larger', 'largerEq', 'SparseMatrix'];
const createSlu = exports.createSlu = /* #__PURE__ */(0, _factory.factory)(name, dependencies, _ref => {
let {
typed,
abs,
add,
multiply,
transpose,
divideScalar,
subtract,
larger,
largerEq,
SparseMatrix
} = _ref;
const csSqr = (0, _csSqr.createCsSqr)({
add,
multiply,
transpose
});
const csLu = (0, _csLu.createCsLu)({
abs,
divideScalar,
multiply,
subtract,
larger,
largerEq,
SparseMatrix
});
/**
* Calculate the Sparse Matrix LU decomposition with full pivoting. Sparse Matrix `A` is decomposed in two matrices (`L`, `U`) and two permutation vectors (`pinv`, `q`) where
*
* `P * A * Q = L * U`
*
* Syntax:
*
* math.slu(A, order, threshold)
*
* Examples:
*
* const A = math.sparse([[4,3], [6, 3]])
* math.slu(A, 1, 0.001)
* // returns:
* // {
* // L: [[1, 0], [1.5, 1]]
* // U: [[4, 3], [0, -1.5]]
* // p: [0, 1]
* // q: [0, 1]
* // }
*
* See also:
*
* lup, lsolve, usolve, lusolve
*
* @param {SparseMatrix} A A two dimensional sparse matrix for which to get the LU decomposition.
* @param {Number} order The Symbolic Ordering and Analysis order:
* 0 - Natural ordering, no permutation vector q is returned
* 1 - Matrix must be square, symbolic ordering and analisis is performed on M = A + A'
* 2 - Symbolic ordering and analisis is performed on M = A' * A. Dense columns from A' are dropped, A recreated from A'.
* This is appropriatefor LU factorization of unsymmetric matrices.
* 3 - Symbolic ordering and analisis is performed on M = A' * A. This is best used for LU factorization is matrix M has no dense rows.
* A dense row is a row with more than 10*sqr(columns) entries.
* @param {Number} threshold Partial pivoting threshold (1 for partial pivoting)
*
* @return {Object} The lower triangular matrix, the upper triangular matrix and the permutation vectors.
*/
return typed(name, {
'SparseMatrix, number, number': function (a, order, threshold) {
// verify order
if (!(0, _number.isInteger)(order) || order < 0 || order > 3) {
throw new Error('Symbolic Ordering and Analysis order must be an integer number in the interval [0, 3]');
}
// verify threshold
if (threshold < 0 || threshold > 1) {
throw new Error('Partial pivoting threshold must be a number from 0 to 1');
}
// perform symbolic ordering and analysis
const s = csSqr(order, a, false);
// perform lu decomposition
const f = csLu(a, s, threshold);
// return decomposition
return {
L: f.L,
U: f.U,
p: f.pinv,
q: s.q,
toString: function () {
return 'L: ' + this.L.toString() + '\nU: ' + this.U.toString() + '\np: ' + this.p.toString() + (this.q ? '\nq: ' + this.q.toString() : '') + '\n';
}
};
}
});
});