57 lines
1.9 KiB
JavaScript
57 lines
1.9 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.csReach = csReach;
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var _csMarked = require("./csMarked.js");
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var _csMark = require("./csMark.js");
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var _csDfs = require("./csDfs.js");
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// Copyright (c) 2006-2024, Timothy A. Davis, All Rights Reserved.
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// SPDX-License-Identifier: LGPL-2.1+
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// https://github.com/DrTimothyAldenDavis/SuiteSparse/tree/dev/CSparse/Source
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/**
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* The csReach function computes X = Reach(B), where B is the nonzero pattern of the n-by-1
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* sparse column of vector b. The function returns the set of nodes reachable from any node in B. The
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* nonzero pattern xi of the solution x to the sparse linear system Lx=b is given by X=Reach(B).
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*
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* @param {Matrix} g The G matrix
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* @param {Matrix} b The B matrix
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* @param {Number} k The kth column in B
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* @param {Array} xi The nonzero pattern xi[top] .. xi[n - 1], an array of size = 2 * n
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* The first n entries is the nonzero pattern, the last n entries is the stack
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* @param {Array} pinv The inverse row permutation vector
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*
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* @return {Number} The index for the nonzero pattern
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*/
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function csReach(g, b, k, xi, pinv) {
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// g arrays
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const gptr = g._ptr;
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const gsize = g._size;
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// b arrays
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const bindex = b._index;
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const bptr = b._ptr;
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// columns
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const n = gsize[1];
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// vars
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let p, p0, p1;
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// initialize top
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let top = n;
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// loop column indeces in B
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for (p0 = bptr[k], p1 = bptr[k + 1], p = p0; p < p1; p++) {
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// node i
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const i = bindex[p];
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// check node i is marked
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if (!(0, _csMarked.csMarked)(gptr, i)) {
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// start a dfs at unmarked node i
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top = (0, _csDfs.csDfs)(i, g, top, xi, pinv);
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}
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}
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// loop columns from top -> n - 1
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for (p = top; p < n; p++) {
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// restore G
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(0, _csMark.csMark)(gptr, xi[p]);
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}
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return top;
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}
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