basker_def.hpp

// @HEADER
// *****************************************************************************
//                   Basker: A Direct Linear Solver package
//
// Copyright 2011 NTESS and the Basker contributors.
// SPDX-License-Identifier: LGPL-2.1-or-later
// *****************************************************************************
// @HEADER
 
#ifndef BASKER_DEF_HPP
#define BASKER_DEF_HPP
 
#include "basker_decl.hpp"
#include "basker_scalartraits.hpp"
//#include "basker.hpp"
 
//#include <cassert>
#include <iostream>
#include <cstdio>
 
//#define BASKER_DEBUG 1
//#undef UDEBUG
 
namespace BaskerClassicNS{
 
  template <class Int, class Entry>
  BaskerClassic<Int, Entry>::BaskerClassic()
  {
 
    //A = (basker_matrix<Int,Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    A = new basker_matrix<Int,Entry>;
 
    //L = (basker_matrix<Int,Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    L = new basker_matrix<Int, Entry>;
    L->nnz = 0;
 
    //U = (basker_matrix<Int,Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    U = new basker_matrix<Int,Entry>;
    U->nnz = 0;
 
    actual_lnnz = Int(0);
    actual_unnz = Int(0);
 
    been_fact = false;
    perm_flag = false;
  }
 
 
  template <class Int, class Entry>
  BaskerClassic<Int, Entry>::BaskerClassic(Int nnzL, Int nnzU)
  {
 
    //A = (basker_matrix<Int, Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    A = new basker_matrix<Int, Entry>;
    //L = (basker_matrix<Int, Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    L = new basker_matrix<Int, Entry>;
    L->nnz = nnzL;
    //U = (basker_matrix<Int, Entry> *) malloc(sizeof(basker_matrix<Int,Entry>));
    U = new basker_matrix<Int, Entry>;
    U->nnz = nnzU;
 
    actual_lnnz = Int(0);
    actual_unnz = Int(0);
 
    been_fact = false;
    perm_flag = false;
  }
 
 
  template <class Int, class Entry>
  BaskerClassic<Int, Entry>::~BaskerClassic()
  {
    //free factor
    if(been_fact)
      {
        free_factor();
        //BASKERFREE(pinv);
        delete [] pinv;
      }
    if(perm_flag)
      {
        //free_perm_matrix();
      }
    //BASKERFREE(A);
    delete A;
    //BASKERFREE(L);
    delete L;
    //BASKERFREE(U);
    delete U;
  }
 
 
  template <class Int, class Entry>
  int BaskerClassic<Int,Entry>:: basker_dfs
  (
   Int n,
   Int j,
   Int *Li,
   Int *Lp,
   Int *color,
   Int *pattern, /* o/p */
   Int *top,       /* o/p */
   //Int k,
   Int *tpinv,
   Int *stack
  )
  {
 
    Int i, t, i1, head ;
    Int start, end, done, *store ;
 
    store = stack + n ;
    head = 0;
    stack[head] = j;
    bool has_elements = true;
 
    while(has_elements)
      {
        j = stack[head] ;
#ifdef BASKER_DEBUG
        //std::cout << "DFS: " << j << "COLOR: " << color[j] << std::endl;
#endif
        t = tpinv [j] ;
        if (color[j] == 0)
          {
            /* Seeing this column for first time */
            color[j] = 1 ;
            start = Lp[t] ;
          }
        else
          {
            BASKERASSERT (color[j] == 1) ; /* color cannot be 2 when we are here */
            start = store[j];
          }
        done = 1;
 
        if ( t != n )
          {
            end = Lp[t+1] ;
            for ( i1 = start ; i1 < end ; i1++ )
              {
                i = Li[i1] ;
                if ( color[i] == 0 )
                  {
                    stack[++head] = i;
                    store[j] = i1+1;
                    done = 0;
                    break;
                  }
              }
          }
        if (done)
          {
            pattern[--*top] = j ;
            color[j] = 2 ;
            if(head == 0)
              {
                has_elements = false;
              }
            else
              {
                head--;
              }
          }
      }
#ifdef BASKER_DEBUG
    std::cout << "Out of DFS: " << j << std::endl;
#endif
    return 0;
  } //End dfs
 
  template <class Int, class Entry>
  int BaskerClassic<Int,Entry>::factor(Int nrow, Int ncol , Int nnz, Int *col_ptr, Int *row_idx, Entry *val)
  {
    int ierr = 0;
    /*Initalize A basker matrix struc */
#ifdef  BASKER_DEBUG
 
    BASKERASSERT(nrow > 0);
    BASKERASSERT(ncol > 0);
    BASKERASSERT(nnz > 0);
 
#endif
 
    A->nrow = nrow;
    A->ncol = ncol;
    A->nnz = nnz;
    A->col_ptr = col_ptr;
    A->row_idx = row_idx;
    A->val = val;
    /*End initalize A*/
 
    //free factor
    if(been_fact)
      {
        free_factor();
        //BASKERFREE(pinv);
        delete [] pinv;
      }
 
    /*Creating space for L and U*/
    L->nrow = nrow;
    L->ncol = ncol;
    if(L->nnz == 0)
      {
        L->nnz = 2*A->nnz;
      }
    //L->col_ptr = (Int *) BASKERCALLOC(ncol+1, sizeof(Int));
    L->col_ptr = new Int[ncol+1]();
    //L->row_idx = (Int *) BASKERCALLOC(L->nnz, sizeof(Int));
    L->row_idx = new Int[L->nnz]();
    //L->val =     (Entry *) BASKERCALLOC(L->nnz, sizeof(Entry));
    L->val =  new Entry[L->nnz]();
 
    U->nrow = nrow;
    U->ncol = ncol;
    if(U->nnz == 0)
      {
        U->nnz = 2*A->nnz;
      }
    //U->col_ptr = (Int *) BASKERCALLOC(ncol+1, sizeof(Int));
    U->col_ptr = new Int[ncol+1]();
    //U->row_idx = (Int *) BASKERCALLOC(U->nnz, sizeof(Int));
    U->row_idx = new Int[U->nnz]();
    //U->val =     (Entry *) BASKERCALLOC(U->nnz, sizeof(Entry));
    U->val = new Entry[U->nnz]();
 
    if((L->col_ptr == nullptr) || (L->row_idx == nullptr) || (L->val == nullptr) ||
       (U->col_ptr == nullptr) || (U->row_idx == nullptr) || (U->val == nullptr))
      {
        ierr = -1;
        return ierr;
      }
    /*End creating space for L and U*/
 
    /*Creating working space*/
    Int *color, *pattern, *stack; 
    Entry *X;
    color = new Int[ncol]();
    pattern = new Int[nrow]();
    stack = new Int[2*nrow]();
    //X =    (Entry *) BASKERCALLOC(2*nrow, sizeof(Entry));
    X = new Entry[2*nrow]();
    //pinv = (Int * )  BASKERCALLOC(ncol+1, sizeof(Int)); //Note extra pad
    pinv = new Int[ncol+1]();
 
 
    if( (color == nullptr) || (pattern == nullptr) || (stack == nullptr) || (X == nullptr) || (pinv == nullptr) )
      {
        ierr = -2;
        return ierr;
      }
 
    /*End creating working space */
 
    /*Defining Variables Used*/
    Int i, j, k;
    Int top, top1, maxindex, t; // j1, j2;
    Int lnnz, unnz, xnnz, lcnt, ucnt;
    Int cu_ltop, cu_utop;
    Int pp, p2, p;
    Int newsize;
    Entry pivot, value, xj;
    Entry absv, maxv;
 
    cu_ltop = 0;
    cu_utop = 0;
    top =  ncol;
    top1 = ncol;
    lnnz = 0; //real found lnnz
    unnz = 0; //real found unnz
 
    for(k = 0 ; k < ncol; k++)
      {
        pinv[k] = ncol;
      }
 
    /*For all columns in A .... */
    for (k = 0; k < ncol; k++)
      {
 
#ifdef BASKER_DEBUG
        std::cout << "k = " << k << std::endl;
#endif
 
        value = 0.0;
        pivot = 0.0;
        maxindex = ncol;
        //j1 = 0;
        //j2 = 0;
        lcnt = 0;
        ucnt = 0;
 
#ifdef BASKER_DEBUG
        BASKERASSERT (top == ncol);
 
        for(i = 0; i < nrow; i++)
          {
            BASKERASSERT(X[i] == (Entry)0);
          }
        for(i = 0; i < ncol; i++)
          {
            BASKERASSERT(color[i] == 0);
          }
#endif
        /* Reachability for every nonzero in Ak */
        for( i = col_ptr[k];  i < col_ptr[k+1]; i++)
          {
            j = row_idx[i];
            X[j] = val[i];
 
            if(color[j] == 0)
              {
                //do dfs
                basker_dfs(nrow, j, L->row_idx, L->col_ptr, color, pattern, &top, pinv, stack);
 
              }
 
          }//end reachable
 
        xnnz = ncol - top;
#ifdef BASKER_DEBUG
        std::cout << top << std::endl;
        std::cout << ncol << std::endl;
        std::cout << xnnz << std::endl;
        //BASKERASSERT(xnnz <= nrow);
#endif
        /*Lx = b where x will be the column k in L and U*/
        top1 = top;
        for(pp = 0; pp < xnnz; pp++)
          {
            j = pattern[top1++];
            color[j] = 0;
            t = pinv[j];
 
            if(t!=ncol) //it has not been assigned
              {
                xj = X[j];
                p2 = L->col_ptr[t+1];
                for(p = L->col_ptr[t]+1; p < p2; p++)
                  {
                    X[L->row_idx[p]] -= L->val[p] * xj;
                  }//over all rows
              }
 
          }
 
        /*get the pivot*/
        maxv = 0.0;
        for(i = top; i < nrow; i++)
          {
            j = pattern[i];
            t = pinv[j];
            value = X[j];
            /*note may want to change this to traits*/
            //absv = (value < 0.0 ? -value : value);
            absv = BASKER_ScalarTraits<Entry>::approxABS(value);
 
            if(t == ncol)
              {
                lcnt++;
                if( BASKER_ScalarTraits<Entry>::gt(absv , maxv))
                  //if(absv > BASKER_ScalarTraits<Entry>::approxABS(maxv))
                 {
                    maxv = absv;
                    pivot = value;
                    maxindex= j;
                  }
              }
          }
        ucnt = nrow - top - lcnt + 1;
 
        if(maxindex == ncol || pivot == ((Entry)0))
          {
            std::cout << "Matrix is singular at index: " << maxindex << " pivot: " << pivot << std::endl;
            ierr = maxindex;
            return ierr;
          }
 
        pinv[maxindex] = k;
#ifdef BASKER_DEBUG
        if(maxindex != k )
          {
            std::cout << "Permuting pivot: " << k << " for row: " << maxindex << std::endl;
          }
#endif
 
        if(lnnz + lcnt >= L->nnz)
          {
 
            newsize = L->nnz * 1.1 + 2*nrow + 1;
#ifdef BASKER_DEBUG
            std::cout << "Out of memory -- Reallocating.  Old Size: " << L->nnz << " New Size: " << newsize << std::endl;
#endif
            //L->row_idx = (Int *) BASKERREALLOC(L->row_idx, newsize*sizeof(Int));
            L->row_idx = int_realloc(L->row_idx , L->nnz, newsize);
            if(!(L->row_idx))
              {
                std::cout << "WARNING: Cannot Realloc Memory" << std::endl;
                ierr = -3;
                return ierr;
              }
            //L->val = (Entry *) BASKERREALLOC(L->val, newsize*sizeof(Entry));
            L->val = entry_realloc(L->val, L->nnz, newsize);
            if(!(L->val))
              {
                std::cout << "WARNING: Cannot Realloc Memory" << std::endl;
                ierr = -3;
                return ierr;
              }
            L->nnz = newsize;
 
          }//realloc if L is out of memory
 
        if(unnz + ucnt >= U->nnz)
          {
            newsize = U->nnz*1.1 + 2*nrow + 1;
#ifdef BASKER_DEBUG
            std::cout << "Out of memory -- Reallocating.  Old Size: " << U->nnz << " New Size: " << newsize << std::endl;
#endif
            //U->row_idx = (Int *) BASKERREALLOC(U->row_idx, newsize*sizeof(Int));
            U->row_idx = int_realloc(U->row_idx, U->nnz, newsize);
            if(!(U->row_idx))
              {
                std::cout << "WARNING: Cannot Realloc Memory" << std::endl;
                ierr = -3;
                return ierr;
              }
 
            //U->val = (Entry *) BASKERREALLOC(U->val, newsize*sizeof(Entry));
            U->val = entry_realloc(U->val, U->nnz, newsize);
            if(!(U->val))
              {
                std::cout << "WARNING: Cannot Realloc Memory" << std::endl;
                ierr = -3;
                return ierr;
              }
            U->nnz = newsize;
          }//realloc if U is out of memory
 
        //L->col_ptr[lnnz] = maxindex;
        L->row_idx[lnnz] = maxindex;
        L->val[lnnz] = 1.0;
        lnnz++;
 
        Entry last_v_temp = 0;
 
        for(i = top; i < nrow; i++)
          {
            j = pattern[i];
            t = pinv[j];
 
            /* check for numerical cancellations */
 
 
            if(X[j] != ((Entry)0))
              {
 
                if(t != ncol)
                  {
                    if(unnz >= U->nnz)
                      {
                        std::cout << "BASKER: Insufficent memory for U" << std::endl;
                        ierr = -3;
                        return ierr;
                      }
                    if(t < k)
                    //if(true)
                      {
                        U->row_idx[unnz] = pinv[j];
                        U->val[unnz] = X[j];
                        unnz++;
                      }
                    else
                      {
 
                        last_v_temp = X[j];
                        //std::cout << "Called.  t: " << t << "Val: " << last_v_temp << std::endl;
                      }
 
                  }
                else if (t ==  ncol)
                  {
                    if(lnnz >= L->nnz)
                      {
                        std::cout << "BASKER: Insufficent memory for L" << std::endl;
                        ierr = -3;
                        return ierr;
                      }
 
                    L->row_idx[lnnz]  = j;
                    //L->val[lnnz] = X[j]/pivot;
                    L->val[lnnz] = BASKER_ScalarTraits<Entry>::divide(X[j],pivot);
                    lnnz++;
 
                  }
 
              }
 
 
            X[j] = 0;
 
          }
        //std::cout << "Value added at end: " << last_v_temp << std::endl;
        U->row_idx[unnz] = k;
        U->val[unnz] = last_v_temp;
        unnz++;
 
        xnnz = 0;
        top = ncol;
 
        L->col_ptr[k] = cu_ltop;
        L->col_ptr[k+1] = lnnz;
        cu_ltop = lnnz;
 
        U->col_ptr[k] = cu_utop;
        U->col_ptr[k+1] = unnz;
        cu_utop = unnz;
 
      } //end for every column
 
#ifdef BASKER_DEBUG
    /*Print out found L and U*/
    for(k = 0; k < lnnz; k++)
      {
        printf("L[%d]=%g" , k , L->val[k]);
      }
    std::cout << std::endl;
    for(k = 0; k < lnnz; k++)
      {
        printf("Li[%d]=%d", k, L->row_idx[k]);
      }
    std::cout << std::endl;
    for(k = 0; k < nrow; k++)
      {
        printf("p[%d]=%d", k, pinv[k]);
      }
    std::cout << std::endl;
    std::cout << std::endl;
 
    for(k = 0; k < ncol; k++)
      {
        printf("Up[%d]=%d", k, U->col_ptr[k]);
      }
    std::cout << std::endl;
 
    for(k = 0; k < unnz; k++)
      {
        printf("U[%d]=%g" , k , U->val[k]);
      }
    std::cout << std::endl;
    for(k = 0; k < unnz; k++)
      {
        printf("Ui[%d]=%d", k, U->row_idx[k]);
      }
    std::cout << std::endl;
 
 
#endif
    /*  Repermute   */
    for( i = 0; i < ncol; i++)
      {
        for(k = L->col_ptr[i]; k < L->col_ptr[i+1]; k++)
          {
            //L->row_idx[k] = pinv[L->row_idx[k]];
          }
      }
    //Max sure correct location of min in L and max in U for CSC format//
    //Speeds up tri-solve//
    //sort_factors();
 
#ifdef BASKER_DEBUG
    std::cout << "After Permuting" << std::endl;
    for(k = 0; k < lnnz; k++)
      {
        printf("Li[%d]=%d", k, L->row_idx[k]);
      }
    std::cout << std::endl;
#endif
 
    // Cleanup workspace allocations
    delete [] X;
    delete [] color;
    delete [] pattern;
    delete [] stack;
 
    actual_lnnz = lnnz;
    actual_unnz = unnz;
 
    been_fact = true;
    return 0;
  }//end factor
 
 
  template <class Int, class Entry>
  Int BaskerClassic<Int, Entry>::get_NnzL()
  {
    return actual_lnnz;
  }
 
  template <class Int, class Entry>
  Int BaskerClassic<Int, Entry>::get_NnzU()
  {
    return actual_unnz;
  }
 
  template <class Int, class Entry>
  Int BaskerClassic<Int, Entry>::get_NnzLU()
  {
    return (actual_lnnz + actual_unnz);
  }
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::returnL(Int *dim, Int *nnz, Int **col_ptr, Int **row_idx, Entry **val)
  {
    int i;
    *dim = L->nrow;
    *nnz = L->nnz;
 
    /*Does a bad copy*/
 
    //*col_ptr = (Int *)   BASKERCALLOC(L->nrow+1, sizeof(Int));
    *col_ptr = new Int[L->nrow+1];
    //*row_idx = (Int *)   BASKERCALLOC(L->nnz, sizeof(Int));
    *row_idx = new Int[L->nnz];
    //*val     = (Entry *) BASKERCALLOC(L->nnz, sizeof(Entry));
    *val = new Entry[L->nnz];
 
    if( (*col_ptr == nullptr) || (*row_idx == nullptr) || (*val == nullptr) )
      {
        return -1;
      }
 
    for(i = 0; i < L->nrow+1; i++)
      {
        (*col_ptr)[i] = L->col_ptr[i];
      }
 
    for(i = 0; i < actual_lnnz; i++)
      {
        (*row_idx)[i] = pinv[L->row_idx[i]];
        (*val)[i]     = L->val[i];
      }
    return 0;
 
  }
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::returnU(Int *dim, Int *nnz, Int **col_ptr, Int **row_idx, Entry **val)
  {
    int i;
    *dim = U->nrow;
    *nnz = U->nnz;
    /*Does a bad copy*/
    //*col_ptr = (Int *)   BASKERCALLOC(U->nrow+1, sizeof(Int));
    *col_ptr = new Int[U->nrow+1];
    //*row_idx = (Int *)   BASKERCALLOC(U->nnz, sizeof(Int));
    *row_idx = new Int[U->nnz];
    //*val     = (Entry *) BASKERCALLOC(U->nnz, sizeof(Entry));
    *val = new Entry[U->nnz];
 
    if( (*col_ptr == nullptr) || (*row_idx == nullptr) || (*val == nullptr) )
      {
        return -1;
      }
 
    for(i = 0; i < U->nrow+1; i++)
      {
        (*col_ptr)[i] = U->col_ptr[i];
      }
    for(i = 0; i < actual_unnz; i++)
      {
        (*row_idx)[i] = U->row_idx[i];
        (*val)[i]     = U->val[i];
      }
    return 0;
  }
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::returnP(Int** p)
  {
    Int i;
    //*p = (Int *) BASKERCALLOC(A->nrow, sizeof(Int));
    *p = new Int[A->nrow];
 
    if( (*p == nullptr ) )
      {
        return -1;
      }
 
    for(i = 0; i < A->nrow; i++)
      {
        (*p)[pinv[i]] = i;  //Matlab perm-style
      }
    return 0;
  }
 
  template <class Int, class Entry>
  void BaskerClassic<Int, Entry>::free_factor()
  {
    //BASKERFREE L
    //BASKERFREE(L->col_ptr);
    delete[] L->col_ptr;
    //BASKERFREE(L->row_idx);
    delete[] L->row_idx;
    //BASKERFREE(L->val);
    delete[] L->val;
 
    //BASKERFREE U
    //BASKERFREE(U->col_ptr);
    delete[] U->col_ptr;
    //BASKERFREE(U->row_idx);
    delete[] U->row_idx;
    //BASKERFREE(U->val);
    delete[] U->val;
 
    been_fact = false;
  }
  template <class Int, class Entry>
  void BaskerClassic<Int, Entry>::free_perm_matrix()
  {
    //BASKERFREE(A->col_ptr);
    //BASKERFREE(A->row_idx);
    //BASKERFREE(A->val);
  }
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::solveMultiple(Int nrhs, Entry *b, Entry *x)
  {
    Int i;
    for(i = 0; i < nrhs; i++)
      {
        Int k = i*A->nrow;
        int result = solve(&(b[k]), &(x[k]));
        if(result != 0)
          {
            std::cout << "Error in Solving \n";
            return result;
          }
      }
    return 0;
  }
 
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::solve(Entry* b, Entry* x)
  {
 
    if(!been_fact)
      {
        return -10;
      }
    //Entry* temp = (Entry *)BASKERCALLOC(A->nrow, sizeof(Entry));
    Entry* temp = new Entry[A->nrow]();
    Int i;
    int result = 0;
    for(i = 0 ; i < A->ncol; i++)
      {
        Int k = pinv[i];
        x[k] = b[i];
      }
 
    result = low_tri_solve_csc(L->nrow, L->col_ptr, L->row_idx, L->val, temp, x);
    if(result == 0)
      {
        result = up_tri_solve_csc(U->nrow, U->col_ptr, U->row_idx, U->val, x, temp);
      }
 
 
    //BASKERFREE(temp);
    delete[] temp;
    return 0;
  }
 
  template < class Int, class Entry>
  int BaskerClassic<Int, Entry>::low_tri_solve_csc( Int n, Int *col_ptr, Int *row_idx, Entry* val,   Entry *x, Entry *b)
  {
    Int i, j;
    /*for each column*/
    for(i = 0; i < n ; i++)
      {
#ifdef BASKER_DEBUG
        BASKERASSERT(val[col_ptr[i]] != (Entry)0);
#else
        if(val[col_ptr[i]] == (Entry) 0)
          {
            return i;
          }
#endif
        x[i] = BASKER_ScalarTraits<Entry>::divide(b[i], val[col_ptr[i]]);
 
        for(j = col_ptr[i]+1; j < (col_ptr[i+1]); j++) //update all rows
          {
            b[pinv[row_idx[j]]] = b[pinv[row_idx[j]]] - (val[j]*x[i]);
          }
      }
    return 0;
  }
 
  template < class Int, class Entry>
  int BaskerClassic<Int, Entry>::up_tri_solve_csc( Int n, Int *col_ptr, Int *row_idx, Entry *val, Entry *x,  Entry *b)
  {
    Int i, j;
    /*for each column*/
    for(i = n; i > 1 ; i--)
      {
        int ii = i-1;
#ifdef BASKER_DEBUG
        BASKERASSERT(val[col_ptr[i]-1] != (Entry)0);
#else
        if(val[col_ptr[i]-1] == (Entry) 0)
          {
            std::cout << "Dig(" << i << ") = " << val[col_ptr[i]-1] << std::endl;
            return i;
          }
#endif
        //x[ii] = b[ii]/val[col_ptr[i]-1]; //diag
        x[ii] = BASKER_ScalarTraits<Entry>::divide(b[ii],val[col_ptr[i]-1]);
 
        for(j = (col_ptr[i]-2); j >= (col_ptr[ii]); j--)
          {
            b[row_idx[j]] = b[row_idx[j]] - (val[j]*x[ii]);
          }
      }
    //x[0] = b[0]/val[col_ptr[1]-1];
    x[0] = BASKER_ScalarTraits<Entry>::divide(b[0],val[col_ptr[1]-1]);
    return 0;
  }
 
  template <class Int, class Entry>
  int BaskerClassic<Int, Entry>::preorder(Int *row_perm, Int *col_perm)
  {
 
    basker_matrix <Int, Entry> *B;
    B = new basker_matrix<Int, Entry>;
    B->nrow = A->nrow;
    B->ncol = A->ncol;
    B->nnz = A->nnz;
    B->col_ptr = (Int *) BASKERCALLOC(A->ncol + 1, sizeof(Int));
    B->row_idx = (Int *) BASKERCALLOC(A->nnz, sizeof(Int));
    B->val     = (Entry *) BASKERCALLOC(A->val, sizeof(Int));
 
    if( (B->col_ptr == nullptr) || (B->row_idx == nullptr) || (B->val == nullptr) )
      {
        perm_flag = false;
        return -1;
      }
 
    /* int resultcol = (unused) */ (void) permute_column(col_perm, B);
    /* int resultrow = (unused) */ (void) permute_row(row_perm, B);
 
    /*Note: the csc matrices of A are the problem of the user
      therefore we will not free them*/
    A->col_ptr = B->col_ptr;
    A->row_idx = B->row_idx;
    A->val     = A->val;
 
    perm_flag = true; /*Now we will free A at the end*/
 
    return 0;
  }
 
  template <class Int, class Entry>
  int BaskerClassic <Int, Entry>::permute_column(Int *p, basker_matrix<Int,Entry> *B)
  {
    /*p(i) contains the destination of row i in the permuted matrix*/
    Int i,j, ii, jj;
 
    /*Determine column pointer of output matrix*/
    for(j=0; j < B->ncol; j++)
      {
        i = p[j];
        B->col_ptr[i+1] = A->col_ptr[j+1] - A->col_ptr[j];
      }
    /*get pointers from lengths*/
    B->col_ptr[0] = 0;
    for(j=0; j < B->ncol; j++)
      {
        B->col_ptr[j+1] = B->col_ptr[j+1] + B->col_ptr[j];
      }
 
    /*copy idxs*/
    Int k, ko;
    for(ii = 0 ; ii < B->ncol; ii++)
      {// old colum ii    new column p[ii]   k->pointer
        ko = B->col_ptr(p[ii]);
        for(k = A->col_ptr[ii]; k < A->col_ptr[ii+1]; k++)
          {
            B->row_index[ko] = A->row_index[k];
            B->val[ko] = A->val[ko];
            ko++;
          }
      }
    return 0;
  }
 
  template <class Int, class Entry>
  int BaskerClassic <Int, Entry>::permute_row(Int *p,  basker_matrix<Int,Entry> *B)
  {
    Int k,i;
    for(k=0; k < A->nnz; k++)
      {
        B->row_idx[k] = p[A->row_idx[k]];
      }
    return 0;
  }
 
  template <class Int, class Entry>
  int BaskerClassic <Int, Entry>::sort_factors()
  {
 
    /*Sort CSC of L - just make sure min_index is in lowest position*/
    Int i, j;
    Int p;
    Int val;
    for(i = 0 ; i < L->ncol; i++)
      {
        p = L->col_ptr[i];
        val = L->row_idx[p];
 
        for(j = L->col_ptr[i]+1; j < (L->col_ptr[i+1]); j++)
          {
            if(L->row_idx[j] < val)
              {
                p = j;
                val = L->row_idx[p];
              }
          }
        Int temp_index = L->row_idx[L->col_ptr[i]];
        Entry temp_entry = L->val[L->col_ptr[i]];
        L->row_idx[L->col_ptr[i]] = val;
        L->val[L->col_ptr[i]] = L->val[p];
        L->row_idx[p] = temp_index;
        L->val[p] = temp_entry;
      }//end for all columns
 
 
    /* Sort CSC U --- just make sure max is in right location*/
     for(i = 0 ; i < U->ncol; i++)
      {
        p = U->col_ptr[i+1]-1;
        val = U->row_idx[p];
 
        for(j = U->col_ptr[i]; j < (U->col_ptr[i+1]-1); j++)
          {
            if(U->row_idx[j] > val)
              {
                p = j;
                val = U->row_idx[p];
              }
          }
        Int temp_index = U->row_idx[U->col_ptr[i+1]-1];
        Entry temp_entry = U->val[U->col_ptr[i+1]-1];
        U->row_idx[U->col_ptr[i+1]-1] = val;
        U->val[U->col_ptr[i+1]-1] = U->val[p];
        U->row_idx[p] = temp_index;
        U->val[p] = temp_entry;
      }//end for all columns
 
    return 0;
  }
 
  template <class Int, class Entry>
  Entry*  BaskerClassic <Int, Entry>::entry_realloc(Entry *old , Int old_size, Int new_size)
  {
    Entry *new_entry = new Entry[new_size];
    for(Int i = 0; i < old_size; i++)
      {
        /*Assumption that Entry was own defined copy constructor*/
        new_entry[i] = old[i];
      }
    delete[] old;
    return new_entry;
 
 
  }
  template <class Int, class Entry>
  Int* BaskerClassic <Int, Entry>::int_realloc(Int *old, Int old_size, Int new_size)
  {
    Int *new_int = new Int[new_size];
    for(Int i =0; i < old_size; i++)
      {
        /*Assumption that Int was own defined copy constructor*/
        new_int[i] = old[i];
      }
    delete[] old;
    return new_int;
 
  }
 
 
}//end namespace
#endif