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factorize column_dfs and panel_dfs
This commit is contained in:
Gael Guennebaud
@@ -29,6 +29,132 @@
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*/
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#ifndef SPARSELU_PANEL_DFS_H
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#define SPARSELU_PANEL_DFS_H
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template <typename ScalarVector, typename IndexVector, typename MarkerType, typename Traits>
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void LU_dfs_kernel(const int jj, IndexVector& perm_r,
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int& nseg, IndexVector& panel_lsub, IndexVector& segrep,
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VectorBlock<IndexVector>& repfnz_col, IndexVector& xprune, MarkerType& marker, IndexVector& parent,
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IndexVector& xplore, LU_GlobalLU_t<IndexVector, ScalarVector>& glu,
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int& nextl_col, int krow, Traits& traits
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)
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{
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IndexVector& xsup = glu.xsup;
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IndexVector& supno = glu.supno;
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IndexVector& lsub = glu.lsub;
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IndexVector& xlsub = glu.xlsub;
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int kmark = marker(krow);
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// For each unmarked krow of jj
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marker(krow) = jj;
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int kperm = perm_r(krow);
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if (kperm == IND_EMPTY ) {
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// krow is in L : place it in structure of L(*, jj)
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panel_lsub(nextl_col++) = krow; // krow is indexed into A
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traits.mem_expand(panel_lsub, nextl_col, kmark);
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}
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else
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{
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// krow is in U : if its supernode-representative krep
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// has been explored, update repfnz(*)
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// krep = supernode representative of the current row
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int krep = xsup(supno(kperm)+1) - 1;
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// First nonzero element in the current column:
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int myfnz = repfnz_col(krep);
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if (myfnz != IND_EMPTY )
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{
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// Representative visited before
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if (myfnz > kperm ) repfnz_col(krep) = kperm;
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}
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else
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{
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// Otherwise, perform dfs starting at krep
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int oldrep = IND_EMPTY;
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parent(krep) = oldrep;
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repfnz_col(krep) = kperm;
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int xdfs = xlsub(krep);
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int maxdfs = xprune(krep);
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int kpar;
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do
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{
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// For each unmarked kchild of krep
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while (xdfs < maxdfs)
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{
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int kchild = lsub(xdfs);
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xdfs++;
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int chmark = marker(kchild);
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if (chmark != jj )
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{
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marker(kchild) = jj;
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int chperm = perm_r(kchild);
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if (chperm == IND_EMPTY)
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{
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// case kchild is in L: place it in L(*, j)
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panel_lsub(nextl_col++) = kchild;
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traits.mem_expand(panel_lsub, nextl_col, chmark);
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}
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else
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{
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// case kchild is in U :
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// chrep = its supernode-rep. If its rep has been explored,
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// update its repfnz(*)
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int chrep = xsup(supno(chperm)+1) - 1;
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myfnz = repfnz_col(chrep);
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if (myfnz != IND_EMPTY)
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{ // Visited before
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if (myfnz > chperm)
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repfnz_col(chrep) = chperm;
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}
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else
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{ // Cont. dfs at snode-rep of kchild
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xplore(krep) = xdfs;
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oldrep = krep;
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krep = chrep; // Go deeper down G(L)
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parent(krep) = oldrep;
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repfnz_col(krep) = chperm;
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xdfs = xlsub(krep);
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maxdfs = xprune(krep);
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} // end if myfnz != -1
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} // end if chperm == -1
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} // end if chmark !=jj
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} // end while xdfs < maxdfs
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// krow has no more unexplored nbrs :
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// Place snode-rep krep in postorder DFS, if this
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// segment is seen for the first time. (Note that
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// "repfnz(krep)" may change later.)
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// Baktrack dfs to its parent
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if(traits.update_segrep(krep,jj))
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//if (marker1(krep) < jcol )
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{
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segrep(nseg) = krep;
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++nseg;
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//marker1(krep) = jj;
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}
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kpar = parent(krep); // Pop recursion, mimic recursion
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if (kpar == IND_EMPTY)
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break; // dfs done
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krep = kpar;
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xdfs = xplore(krep);
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maxdfs = xprune(krep);
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} while (kpar != IND_EMPTY); // Do until empty stack
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} // end if (myfnz = -1)
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} // end if (kperm == -1)
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}
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/**
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* \brief Performs a symbolic factorization on a panel of columns [jcol, jcol+w)
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*
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@@ -62,29 +188,42 @@
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*
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*
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*/
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template<typename IndexVector>
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struct LU_panel_dfs_traits
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{
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typedef typename IndexVector::Scalar Index;
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LU_panel_dfs_traits(Index jcol, Index* marker)
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: m_jcol(jcol), m_marker(marker)
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{}
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bool update_segrep(Index krep, Index jj)
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{
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if(m_marker[krep]<m_jcol)
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{
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m_marker[krep] = jj;
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return true;
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}
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return false;
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}
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void mem_expand(IndexVector& /*lsub*/, int /*nextl*/, int /*chmark*/) {}
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enum { ExpandMem = false };
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Index m_jcol;
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Index* m_marker;
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};
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template <typename MatrixType, typename ScalarVector, typename IndexVector>
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void LU_panel_dfs(const int m, const int w, const int jcol, MatrixType& A, IndexVector& perm_r, int& nseg, ScalarVector& dense, IndexVector& panel_lsub, IndexVector& segrep, IndexVector& repfnz, IndexVector& xprune, IndexVector& marker, IndexVector& parent, IndexVector& xplore, LU_GlobalLU_t<IndexVector, ScalarVector>& glu)
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{
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int jj; // Index through each column in the panel
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int nextl_col; // Next available position in panel_lsub[*,jj]
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int krow; // Row index of the current element
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int kperm; // permuted row index
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int krep; // Supernode representative of the current row
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int kmark;
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int chperm, chmark, chrep, oldrep, kchild;
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int myfnz; // First nonzero element in the current column
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int xdfs, maxdfs, kpar;
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// Initialize pointers
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VectorBlock<IndexVector> marker1(marker, m, m);
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nseg = 0;
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IndexVector& xsup = glu.xsup;
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IndexVector& supno = glu.supno;
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IndexVector& lsub = glu.lsub;
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IndexVector& xlsub = glu.xlsub;
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LU_panel_dfs_traits<IndexVector> traits(jcol, marker1.data());
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// For each column in the panel
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for (jj = jcol; jj < jcol + w; jj++)
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for (int jj = jcol; jj < jcol + w; jj++)
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{
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nextl_col = (jj - jcol) * m;
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@@ -95,114 +234,15 @@ void LU_panel_dfs(const int m, const int w, const int jcol, MatrixType& A, Index
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// For each nnz in A[*, jj] do depth first search
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for (typename MatrixType::InnerIterator it(A, jj); it; ++it)
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{
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krow = it.row();
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dense_col(krow) = it.value();
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kmark = marker(krow);
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int krow = it.row();
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dense_col(krow) = it.value();
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int kmark = marker(krow);
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if (kmark == jj)
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continue; // krow visited before, go to the next nonzero
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// For each unmarked krow of jj
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marker(krow) = jj;
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kperm = perm_r(krow);
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if (kperm == IND_EMPTY ) {
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// krow is in L : place it in structure of L(*, jj)
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panel_lsub(nextl_col++) = krow; // krow is indexed into A
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}
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else
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{
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// krow is in U : if its supernode-representative krep
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// has been explored, update repfnz(*)
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krep = xsup(supno(kperm)+1) - 1;
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myfnz = repfnz_col(krep);
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if (myfnz != IND_EMPTY )
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{
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// Representative visited before
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if (myfnz > kperm ) repfnz_col(krep) = kperm;
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}
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else
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{
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// Otherwise, perform dfs starting at krep
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oldrep = IND_EMPTY;
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parent(krep) = oldrep;
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repfnz_col(krep) = kperm;
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xdfs = xlsub(krep);
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maxdfs = xprune(krep);
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do
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{
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// For each unmarked kchild of krep
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while (xdfs < maxdfs)
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{
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kchild = lsub(xdfs);
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xdfs++;
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chmark = marker(kchild);
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if (chmark != jj )
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{
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marker(kchild) = jj;
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chperm = perm_r(kchild);
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if (chperm == IND_EMPTY)
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{
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// case kchild is in L: place it in L(*, j)
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panel_lsub(nextl_col++) = kchild;
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}
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else
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{
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// case kchild is in U :
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// chrep = its supernode-rep. If its rep has been explored,
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// update its repfnz(*)
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chrep = xsup(supno(chperm)+1) - 1;
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myfnz = repfnz_col(chrep);
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if (myfnz != IND_EMPTY)
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{ // Visited before
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if (myfnz > chperm)
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repfnz_col(chrep) = chperm;
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}
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else
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{ // Cont. dfs at snode-rep of kchild
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xplore(krep) = xdfs;
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oldrep = krep;
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krep = chrep; // Go deeper down G(L)
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parent(krep) = oldrep;
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repfnz_col(krep) = chperm;
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xdfs = xlsub(krep);
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maxdfs = xprune(krep);
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} // end if myfnz != -1
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} // end if chperm == -1
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} // end if chmark !=jj
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} // end while xdfs < maxdfs
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// krow has no more unexplored nbrs :
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// Place snode-rep krep in postorder DFS, if this
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// segment is seen for the first time. (Note that
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// "repfnz(krep)" may change later.)
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// Baktrack dfs to its parent
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if (marker1(krep) < jcol )
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{
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segrep(nseg) = krep;
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++nseg;
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marker1(krep) = jj;
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}
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kpar = parent(krep); // Pop recursion, mimic recursion
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if (kpar == IND_EMPTY)
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break; // dfs done
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krep = kpar;
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xdfs = xplore(krep);
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maxdfs = xprune(krep);
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} while (kpar != IND_EMPTY); // Do until empty stack
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} // end if (myfnz = -1)
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} // end if (kperm == -1)
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LU_dfs_kernel(jj, perm_r, nseg, panel_lsub, segrep, repfnz_col, xprune, marker, parent,
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xplore, glu, nextl_col, krow, traits);
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}// end for nonzeros in column jj
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} // end for column jj
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