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authorjjesswan <jessica_wan@brown.edu>2024-04-22 21:56:26 -0400
committerjjesswan <jessica_wan@brown.edu>2024-04-22 21:56:26 -0400
commita556b45abf18f1bd509daaf63b66b7d55e9fd291 (patch)
treebc9b8a2d184c12aee236e7f9f276a34b84ca552d /engine-ocean/Eigen/src/SparseCholesky/SimplicialCholesky_impl.h
parentcd7c76017a12bb548036571c1ff13e551369d06d (diff)
add engine version
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+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2008-2012 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+/*
+NOTE: these functions have been adapted from the LDL library:
+
+LDL Copyright (c) 2005 by Timothy A. Davis. All Rights Reserved.
+
+The author of LDL, Timothy A. Davis., has executed a license with Google LLC
+to permit distribution of this code and derivative works as part of Eigen under
+the Mozilla Public License v. 2.0, as stated at the top of this file.
+ */
+
+#ifndef EIGEN_SIMPLICIAL_CHOLESKY_IMPL_H
+#define EIGEN_SIMPLICIAL_CHOLESKY_IMPL_H
+
+namespace Eigen {
+
+template<typename Derived>
+void SimplicialCholeskyBase<Derived>::analyzePattern_preordered(const CholMatrixType& ap, bool doLDLT)
+{
+ const StorageIndex size = StorageIndex(ap.rows());
+ m_matrix.resize(size, size);
+ m_parent.resize(size);
+ m_nonZerosPerCol.resize(size);
+
+ ei_declare_aligned_stack_constructed_variable(StorageIndex, tags, size, 0);
+
+ for(StorageIndex k = 0; k < size; ++k)
+ {
+ /* L(k,:) pattern: all nodes reachable in etree from nz in A(0:k-1,k) */
+ m_parent[k] = -1; /* parent of k is not yet known */
+ tags[k] = k; /* mark node k as visited */
+ m_nonZerosPerCol[k] = 0; /* count of nonzeros in column k of L */
+ for(typename CholMatrixType::InnerIterator it(ap,k); it; ++it)
+ {
+ StorageIndex i = it.index();
+ if(i < k)
+ {
+ /* follow path from i to root of etree, stop at flagged node */
+ for(; tags[i] != k; i = m_parent[i])
+ {
+ /* find parent of i if not yet determined */
+ if (m_parent[i] == -1)
+ m_parent[i] = k;
+ m_nonZerosPerCol[i]++; /* L (k,i) is nonzero */
+ tags[i] = k; /* mark i as visited */
+ }
+ }
+ }
+ }
+
+ /* construct Lp index array from m_nonZerosPerCol column counts */
+ StorageIndex* Lp = m_matrix.outerIndexPtr();
+ Lp[0] = 0;
+ for(StorageIndex k = 0; k < size; ++k)
+ Lp[k+1] = Lp[k] + m_nonZerosPerCol[k] + (doLDLT ? 0 : 1);
+
+ m_matrix.resizeNonZeros(Lp[size]);
+
+ m_isInitialized = true;
+ m_info = Success;
+ m_analysisIsOk = true;
+ m_factorizationIsOk = false;
+}
+
+
+template<typename Derived>
+template<bool DoLDLT>
+void SimplicialCholeskyBase<Derived>::factorize_preordered(const CholMatrixType& ap)
+{
+ using std::sqrt;
+
+ eigen_assert(m_analysisIsOk && "You must first call analyzePattern()");
+ eigen_assert(ap.rows()==ap.cols());
+ eigen_assert(m_parent.size()==ap.rows());
+ eigen_assert(m_nonZerosPerCol.size()==ap.rows());
+
+ const StorageIndex size = StorageIndex(ap.rows());
+ const StorageIndex* Lp = m_matrix.outerIndexPtr();
+ StorageIndex* Li = m_matrix.innerIndexPtr();
+ Scalar* Lx = m_matrix.valuePtr();
+
+ ei_declare_aligned_stack_constructed_variable(Scalar, y, size, 0);
+ ei_declare_aligned_stack_constructed_variable(StorageIndex, pattern, size, 0);
+ ei_declare_aligned_stack_constructed_variable(StorageIndex, tags, size, 0);
+
+ bool ok = true;
+ m_diag.resize(DoLDLT ? size : 0);
+
+ for(StorageIndex k = 0; k < size; ++k)
+ {
+ // compute nonzero pattern of kth row of L, in topological order
+ y[k] = Scalar(0); // Y(0:k) is now all zero
+ StorageIndex top = size; // stack for pattern is empty
+ tags[k] = k; // mark node k as visited
+ m_nonZerosPerCol[k] = 0; // count of nonzeros in column k of L
+ for(typename CholMatrixType::InnerIterator it(ap,k); it; ++it)
+ {
+ StorageIndex i = it.index();
+ if(i <= k)
+ {
+ y[i] += numext::conj(it.value()); /* scatter A(i,k) into Y (sum duplicates) */
+ Index len;
+ for(len = 0; tags[i] != k; i = m_parent[i])
+ {
+ pattern[len++] = i; /* L(k,i) is nonzero */
+ tags[i] = k; /* mark i as visited */
+ }
+ while(len > 0)
+ pattern[--top] = pattern[--len];
+ }
+ }
+
+ /* compute numerical values kth row of L (a sparse triangular solve) */
+
+ RealScalar d = numext::real(y[k]) * m_shiftScale + m_shiftOffset; // get D(k,k), apply the shift function, and clear Y(k)
+ y[k] = Scalar(0);
+ for(; top < size; ++top)
+ {
+ Index i = pattern[top]; /* pattern[top:n-1] is pattern of L(:,k) */
+ Scalar yi = y[i]; /* get and clear Y(i) */
+ y[i] = Scalar(0);
+
+ /* the nonzero entry L(k,i) */
+ Scalar l_ki;
+ if(DoLDLT)
+ l_ki = yi / numext::real(m_diag[i]);
+ else
+ yi = l_ki = yi / Lx[Lp[i]];
+
+ Index p2 = Lp[i] + m_nonZerosPerCol[i];
+ Index p;
+ for(p = Lp[i] + (DoLDLT ? 0 : 1); p < p2; ++p)
+ y[Li[p]] -= numext::conj(Lx[p]) * yi;
+ d -= numext::real(l_ki * numext::conj(yi));
+ Li[p] = k; /* store L(k,i) in column form of L */
+ Lx[p] = l_ki;
+ ++m_nonZerosPerCol[i]; /* increment count of nonzeros in col i */
+ }
+ if(DoLDLT)
+ {
+ m_diag[k] = d;
+ if(d == RealScalar(0))
+ {
+ ok = false; /* failure, D(k,k) is zero */
+ break;
+ }
+ }
+ else
+ {
+ Index p = Lp[k] + m_nonZerosPerCol[k]++;
+ Li[p] = k ; /* store L(k,k) = sqrt (d) in column k */
+ if(d <= RealScalar(0)) {
+ ok = false; /* failure, matrix is not positive definite */
+ break;
+ }
+ Lx[p] = sqrt(d) ;
+ }
+ }
+
+ m_info = ok ? Success : NumericalIssue;
+ m_factorizationIsOk = true;
+}
+
+} // end namespace Eigen
+
+#endif // EIGEN_SIMPLICIAL_CHOLESKY_IMPL_H