82 lines
2.7 KiB
JavaScript
82 lines
2.7 KiB
JavaScript
|
"use strict";
|
||
|
|
|
||
|
|
Object.defineProperty(exports, "__esModule", {
|
||
|
|
value: true
|
||
|
|
});
|
||
|
|
exports.csDfs = csDfs;
|
||
|
|
var _csMarked = require("./csMarked.js");
|
||
|
|
var _csMark = require("./csMark.js");
|
||
|
|
var _csUnflip = require("./csUnflip.js");
|
||
|
|
// Copyright (c) 2006-2024, Timothy A. Davis, All Rights Reserved.
|
||
|
|
// SPDX-License-Identifier: LGPL-2.1+
|
||
|
|
// https://github.com/DrTimothyAldenDavis/SuiteSparse/tree/dev/CSparse/Source
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Depth-first search computes the nonzero pattern xi of the directed graph G (Matrix) starting
|
||
|
|
* at nodes in B (see csReach()).
|
||
|
|
*
|
||
|
|
* @param {Number} j The starting node for the DFS algorithm
|
||
|
|
* @param {Matrix} g The G matrix to search, ptr array modified, then restored
|
||
|
|
* @param {Number} top Start index in stack xi[top..n-1]
|
||
|
|
* @param {Number} k The kth column in B
|
||
|
|
* @param {Array} xi The nonzero pattern xi[top] .. xi[n - 1], an array of size = 2 * n
|
||
|
|
* The first n entries is the nonzero pattern, the last n entries is the stack
|
||
|
|
* @param {Array} pinv The inverse row permutation vector, must be null for L * x = b
|
||
|
|
*
|
||
|
|
* @return {Number} New value of top
|
||
|
|
*/
|
||
|
|
function csDfs(j, g, top, xi, pinv) {
|
||
|
|
// g arrays
|
||
|
|
const index = g._index;
|
||
|
|
const ptr = g._ptr;
|
||
|
|
const size = g._size;
|
||
|
|
// columns
|
||
|
|
const n = size[1];
|
||
|
|
// vars
|
||
|
|
let i, p, p2;
|
||
|
|
// initialize head
|
||
|
|
let head = 0;
|
||
|
|
// initialize the recursion stack
|
||
|
|
xi[0] = j;
|
||
|
|
// loop
|
||
|
|
while (head >= 0) {
|
||
|
|
// get j from the top of the recursion stack
|
||
|
|
j = xi[head];
|
||
|
|
// apply permutation vector
|
||
|
|
const jnew = pinv ? pinv[j] : j;
|
||
|
|
// check node j is marked
|
||
|
|
if (!(0, _csMarked.csMarked)(ptr, j)) {
|
||
|
|
// mark node j as visited
|
||
|
|
(0, _csMark.csMark)(ptr, j);
|
||
|
|
// update stack (last n entries in xi)
|
||
|
|
xi[n + head] = jnew < 0 ? 0 : (0, _csUnflip.csUnflip)(ptr[jnew]);
|
||
|
|
}
|
||
|
|
// node j done if no unvisited neighbors
|
||
|
|
let done = 1;
|
||
|
|
// examine all neighbors of j, stack (last n entries in xi)
|
||
|
|
for (p = xi[n + head], p2 = jnew < 0 ? 0 : (0, _csUnflip.csUnflip)(ptr[jnew + 1]); p < p2; p++) {
|
||
|
|
// consider neighbor node i
|
||
|
|
i = index[p];
|
||
|
|
// check we have visited node i, skip it
|
||
|
|
if ((0, _csMarked.csMarked)(ptr, i)) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
// pause depth-first search of node j, update stack (last n entries in xi)
|
||
|
|
xi[n + head] = p;
|
||
|
|
// start dfs at node i
|
||
|
|
xi[++head] = i;
|
||
|
|
// node j is not done
|
||
|
|
done = 0;
|
||
|
|
// break, to start dfs(i)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
// check depth-first search at node j is done
|
||
|
|
if (done) {
|
||
|
|
// remove j from the recursion stack
|
||
|
|
head--;
|
||
|
|
// and place in the output stack
|
||
|
|
xi[--top] = j;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return top;
|
||
|
|
}
|