feat:node-modules

node_modules/mathjs/lib/esm/function/algebra/sparse/csEreach.js

@@ -0,0 +1,63 @@
+// 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
+import { csMark } from './csMark.js';
+import { csMarked } from './csMarked.js';
+
+/**
+ * Find nonzero pattern of Cholesky L(k,1:k-1) using etree and triu(A(:,k))
+ *
+ * @param {Matrix}  a               The A matrix
+ * @param {Number}  k               The kth column in A
+ * @param {Array}   parent          The parent vector from the symbolic analysis result
+ * @param {Array}   w               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
+ *
+ * @return {Number}                 The index for the nonzero pattern
+ */
+export function csEreach(a, k, parent, w) {
+  // a arrays
+  var aindex = a._index;
+  var aptr = a._ptr;
+  var asize = a._size;
+  // columns
+  var n = asize[1];
+  // initialize top
+  var top = n;
+  // vars
+  var p, p0, p1, len;
+  // mark node k as visited
+  csMark(w, k);
+  // loop values & index for column k
+  for (p0 = aptr[k], p1 = aptr[k + 1], p = p0; p < p1; p++) {
+    // A(i,k) is nonzero
+    var i = aindex[p];
+    // only use upper triangular part of A
+    if (i > k) {
+      continue;
+    }
+    // traverse up etree
+    for (len = 0; !csMarked(w, i); i = parent[i]) {
+      // L(k,i) is nonzero, last n entries in w
+      w[n + len++] = i;
+      // mark i as visited
+      csMark(w, i);
+    }
+    while (len > 0) {
+      // decrement top & len
+      --top;
+      --len;
+      // push path onto stack, last n entries in w
+      w[n + top] = w[n + len];
+    }
+  }
+  // unmark all nodes
+  for (p = top; p < n; p++) {
+    // use stack value, last n entries in w
+    csMark(w, w[n + p]);
+  }
+  // unmark node k
+  csMark(w, k);
+  // s[top..n-1] contains pattern of L(k,:)
+  return top;
+}