/*! \legal
  Copyright (C) 2003 -- 2007
  Lou Hafer, International Business Machines Corporation and others.
  All Rights Reserved.

  This file is a portion of the COIN/OSI interface for dylp and is licensed
  under the terms of the Eclipse Public License (EPL)
*/

#include "OsiConfig.h"

#ifdef _MSC_VER

/* Turn off compiler warning about long names */

#  pragma warning(disable:4786)

#endif // _MSC_VER

/* Cut name lengths for readability. */

#define ODWSB OsiDylpWarmStartBasis
#define CWSB CoinWarmStartBasis

/*!
   \file OsiDylpWarmStartBasis.cpp

   \brief Implementation of warm start object for dylp.

  This file contains the implementation of a warm start object for dylp. It
  extends the CoinWarmStartBasis class by adding an explicit list of active
  constraints. When operating in dynamic mode, dylp needs to be told which
  constraints are active in the basis.
  
  For ease of use, constraint status is handled like variable status. There's
  an array, one entry per constraint, coded using CoinWarmStartBasis::Status.
  Inactive constraints are marked with isFree, active constraints with
  atLowerBound. Note that active/inactive is not equivalent to tight/loose.
  The default behaviour in dynamic mode is to purge constraints which are
  strictly loose, but dylp can be instructed to also purge tight constraints
  when the associated dual variable is zero.

*/

#include <vector>
#include <cassert>
#include "OsiDylpWarmStartBasis.hpp"
#include "CoinMessageHandler.hpp"

#ifndef ODSI_PARANOIA
# define ODSI_PARANOIA 1
#endif
// #undef ODSI_PARANOIA
// #define ODSI_PARANOIA 2

/*
  The following symbol is useful only for detailed debugging.

  ODWSB_TRACK_BASIS	track basis manipulations

*/
// #define ODWSB_TRACK_BASIS 1

namespace {
  char sccsid[] UNUSED = "@(#)OsiDylpWarmStartBasis.cpp	1.7	11/06/04" ;
  char cvsid[] UNUSED = "$Id: OsiDylpWarmStartBasis.cpp 1408 2009-10-04 10:27:59Z stefan $" ;
}

using std::vector ;

/*
  A macro to standardize the size of the status arrays. CWSB::Status is the
  status enum, and currently it occupies 2 bits, packed 4 per char (note the
  implicit assumption that a char is 1 byte).  This macro calculates the
  number of bytes needed to hold ns status entires, rounded up to the nearest
  int.
*/

#define STATPERBYTE 4
#define STATALLOCUNIT (static_cast<int>(sizeof(int)))
#define STATBYTES(zz_ns_zz) \
  (((zz_ns_zz+STATALLOCUNIT*STATPERBYTE-1)/(STATALLOCUNIT*STATPERBYTE))* \
   STATALLOCUNIT)
  

/*! \defgroup ODWSBConstructorsDestructors ODWSB Constructors and Destructors
    \brief ODWSB Constructors and destructors

  ODWSB provides a default constructor, several variations on a copy
  constructor, a default destructor, and two variations on assignment.
  There are also routines to change the capacity of the warm start object.
*/
//@{

/*! Creates an empty basis. */

ODWSB::OsiDylpWarmStartBasis ()

  : CWSB(),
    phase_(dyINV),
    constraintStatus_(0)

{ 
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif
}


/*!
  A true copy --- no data structures are shared with the original.
*/

ODWSB::OsiDylpWarmStartBasis (const OsiDylpWarmStartBasis &ws)

  : CWSB(ws),
    phase_(ws.phase_),
    constraintStatus_(0)

{ if (ws.constraintStatus_)
  { int constatsze = STATBYTES(getNumArtificial()) ;
    constraintStatus_ = new char[constatsze] ;
    memcpy(constraintStatus_,ws.constraintStatus_,constatsze) ; }
  
# if ODSI_PARANOIA >= 2
  ws.checkBasis() ;
  checkBasis() ;
# endif

  return ; }


/*!
  `Virtual constructor' method, for when we need to duplicate the ODWSB object
  from code that doesn't know it has an ODSWB object.
*/

CoinWarmStart *ODWSB::clone () const

{ const ODWSB *odwsb_orig = dynamic_cast<const ODWSB *>(this) ;
  ODWSB *odwsb_new = 0 ;
  if (odwsb_orig)
  { odwsb_new = new OsiDylpWarmStartBasis(*odwsb_orig) ; }

# if ODSI_PARANOIA >= 2
  checkBasis() ;
  odwsb_new->checkBasis() ;
# endif

  return (dynamic_cast<CoinWarmStart *>(odwsb_new)) ; }

/*!
  Construct by copying a set of status arrays (parameters preserved). If
  no constraint status is provided, the default is to declare all constraints
  active. The phase is set to dyPRIMAL1, which is safe for any basis.

  Consider assignBasisStatus(int,int,char*&,char*&) if the object should
  assume ownership.
*/

ODWSB::OsiDylpWarmStartBasis
  (int ns, int na, const char *sStat, const char *aStat, const char *cStat)

  : CWSB(ns,na,sStat,aStat),
    phase_(dyPRIMAL1),
    constraintStatus_(0)

{ int constatsze = STATBYTES(na) ;
  constraintStatus_ = new char[constatsze] ;
/*
  If a status array is given, copy it in. If there's no array provided, assume
  all constraints are active. Set up a byte with the correct pattern and use it
  to initialize the constraint status.
*/
  if (cStat)
  { memcpy(constraintStatus_,cStat,constatsze) ; }
  else
  { char byteActive = 0 ;
    int i ;
    for (i = 0 ; i <= 3 ; i++) setStatus(&byteActive,i,CWSB::atLowerBound) ;
    memset(constraintStatus_,byteActive,constatsze) ; }

# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif

  return ; }

/*!
  Construct from a CoinWarmStartBasis.
 
  Much as the previous constructor, but we know we'll need to build the
  constraint status array.
*/

ODWSB::OsiDylpWarmStartBasis (const CoinWarmStartBasis &cwsb)

  : CWSB(cwsb),
    phase_(dyPRIMAL1),
    constraintStatus_(0)

{ int na = cwsb.getNumArtificial() ;
  int constatsze = STATBYTES(na) ;
  constraintStatus_ = new char[constatsze] ;
  char byteActive = 0 ;

  for (int i = 0 ; i <= 3 ; i++) setStatus(&byteActive,i,CWSB::atLowerBound) ;

  memset(constraintStatus_,byteActive,constatsze) ;
  
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif

  return ; }

/*!
  Assignment of structure (parameter preserved)
*/

OsiDylpWarmStartBasis& ODWSB::operator= (const OsiDylpWarmStartBasis &rhs)

{ if (this != &rhs)
  { CWSB::operator=(rhs) ;
    phase_ = rhs.phase_ ;
    delete[] constraintStatus_ ;
    if (rhs.constraintStatus_)
    { int constatsze = STATBYTES(getNumArtificial()) ;
      constraintStatus_ = new char[constatsze] ;
      memcpy(constraintStatus_,rhs.constraintStatus_,constatsze) ; }
    else
    { constraintStatus_ = 0 ; } }
  
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif

  return *this ; }


/*!
  Assignment of status arrays (parameters destroyed). The phase is set to
  dyPRIMAL1, which is safe for any basis.

  In this method the OsiDylpWarmStartBasis object assumes ownership of the
  arrays and upon return the argument pointers will be NULL.
  If copying is desirable, use the
  \link OsiDylpWarmStartBasis(int,int,const char*,const char*,const char*)
	array constructor \endlink
  or the
  \link operator=(const OsiDylpWarmStartBasis&)
	assignment operator \endlink.

  \note
  The pointers passed to this method will be
  freed using delete[], so they must be created using new[].
*/

void ODWSB::assignBasisStatus
  (int ns, int na, char *&sStat, char *&aStat, char *&cStat)

{ CWSB::assignBasisStatus(ns,na,sStat,aStat) ;
  phase_ = dyPRIMAL1 ;
  delete[] constraintStatus_ ;
  constraintStatus_ = cStat ;
  cStat = 0 ;
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif
}

/*!
  Assignment of status arrays (parameters destroyed). When no constraint status
  is provided, the default is to create an array which indicates all
  constraints are active. The phase is set to dyPRIMAL1, which is safe for
  any basis.

  In this method the OsiDylpWarmStartBasis object assumes ownership of the
  arrays and upon return the argument pointers will be NULL.
  If copying is desirable, use the
  \link OsiDylpWarmStartBasis(int,int,const char*,const char*,const char*)
	array constructor \endlink
  or the
  \link operator=(const OsiDylpWarmStartBasis&)
	assignment operator \endlink.

  \note
  The pointers passed to this method will be
  freed using delete[], so they must be created using new[].
*/
void ODWSB::assignBasisStatus (int ns, int na, char *&sStat, char *&aStat)

{ int constatsze = STATBYTES(na) ;
  char byteActive = 0 ;
  int i ;

  CWSB::assignBasisStatus(ns,na,sStat,aStat) ;
  phase_ = dyPRIMAL1 ;

  delete[] constraintStatus_ ;
  constraintStatus_ = new char[constatsze] ;
  for (i = 0 ; i <= 3 ; i++) setStatus(&byteActive,i,CWSB::atLowerBound) ;
  memset(constraintStatus_,byteActive,constatsze) ;
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif
}

ODWSB::~OsiDylpWarmStartBasis () { delete[] constraintStatus_ ; }

/*!
  This routine sets the capacity of the warm start object. Any existing basis
  information is lost.

  The basis is inconsistent at the end of this routine: All constraints are
  active, but there are no basic variables (the status arrays are initialised
  to isFree by CWSB::setSize).
*/

void ODWSB::setSize (int ns, int na)

{ CWSB::setSize(ns,na) ;
  phase_ = dyINV ;
  delete[] constraintStatus_ ;
  if (na > 0)
  { int constatsze = STATBYTES(na) ;
    constraintStatus_ = new char[constatsze] ;
    char byteActive = 0 ;
    for (int i = 0 ; i <= 3 ; i++) setStatus(&byteActive,i,CWSB::atLowerBound) ;
    memset(constraintStatus_,byteActive,constatsze) ; }
  else
  { constraintStatus_ = 0 ; }
  
  return ; }

/*!
  This routine sets the capacity of the warm start object.  Any existing
  basis information is retained. If the new size is smaller than the existing
  basis, the existing basis is truncated to fit.  If the new size is larger
  than the existing basis, additional structural variables are given the
  status nonbasic at lower bound, additional artificial variables are given
  the status basic, and additional constraints are given the status active.

  We need to allow for the possibility that the client has created an empty
  basis and is using resize instead of setSize to get the proper final size.

  The basis is consistent after this routine, even if it starts out as an
  empty basis.
*/

void ODWSB::resize (int numRows, int numCols)

{ int concnt = getNumArtificial() ;
  int varcnt = getNumStructural() ;
  bool empty ;

  if (concnt == 0 && varcnt == 0)
  { empty = true ; }
  else
  { empty = false ;
    assert(constraintStatus_) ; }
  
  CWSB::resize(numRows,numCols) ;

  if (numRows != concnt)
  { int oldsze = STATBYTES(concnt) ;
    int newsze = STATBYTES(numRows) ;
    char *newStat = new char[newsze] ;
/*
  If the new capacity is smaller, truncate the existing basis.
*/
    if (oldsze > newsze)
    { memcpy(newStat,constraintStatus_,newsze) ; }
/*
  If the new capacity is larger, copy the existing basis, then mark the
  additional constraints as active. We need to be a bit careful here, because
  the allocated sizes are rounded out. The strategy is to (possibly) overlap
  one byte, correcting it after initialization.
*/
    else
    { char byteActive = 0 ;
      int i,actualBytes ;
      actualBytes = concnt/STATPERBYTE ;
      for (i = 0 ; i < STATPERBYTE ; i++)
        setStatus(&byteActive,i,CWSB::atLowerBound) ;
      if (empty == false)
      { memcpy(newStat,constraintStatus_,oldsze) ;
	memset(newStat+actualBytes,byteActive,newsze-actualBytes) ;
	for (i = 0 ; i < concnt%STATPERBYTE ; i++)
	{ setStatus(newStat+actualBytes,i,
		    getStatus(constraintStatus_+actualBytes,i)) ; } }
      else
      { memset(newStat,byteActive,newsze) ; } }

    delete [] constraintStatus_ ;
    constraintStatus_ = newStat ; }
  
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif

  return ; }

/*
  compressRows takes an ordered list of target indices without duplicates and
  removes them, compressing the artificialStatus_ and constraintStatus_
  arrays in place. It will fail spectacularly if the indices are not sorted.
  Use deleteRows if you need to preprocess the target indices to satisfy the
  conditions.
*/
void ODWSB::compressRows (int tgtCnt, const int *tgts)
{ 
/*
  Bail out if we're called with nothing to do.
*/
  if (tgtCnt <= 0) return ;

  int i,keep,t,blkStart,blkEnd ;
  Status stati ;

/*
  Depending on circumstances, constraint indices may be larger than the size
  of the basis. Check for that now. Scan from top, betting that in most cases
  the majority of indices will be valid.
*/
  for (t = tgtCnt-1 ; t >= 0 && tgts[t] >= numArtificial_ ; t--) ;
  if (t < 0) return ;
  tgtCnt = t+1 ;

# if ODSI_PARANOIA >= 2
/*
  If we're debugging, scan to see if we're deleting nonbasic artificials.
  (In other words, are we deleting tight constraints?) Easiest to just do this
  up front as opposed to integrating it with the loops below.
*/
  int nbCnt = 0 ;
  for (t = 0 ; t < tgtCnt ; t++)
  { i = tgts[t] ;
    stati = getStatus(artificialStatus_,i) ;
    if (stati != CoinWarmStartBasis::basic)
    { nbCnt++ ; } }
  if (nbCnt > 0)
  { std::cout << nbCnt << " nonbasic artificials deleted." << std::endl ; }
# endif

/*
  We preserve all entries before the first target. Skip across consecutive
  target indices to establish the start of the first block to be retained.
*/
  keep = tgts[0] ;
  for (t = 0 ; t < tgtCnt-1 && tgts[t]+1 == tgts[t+1] ; t++) ;
  blkStart = tgts[t]+1 ;
/*
  Outer loop works through the indices to be deleted. Inner loop copies runs
  of indices to keep.
*/
  while (t < tgtCnt-1)
  { blkEnd = tgts[t+1]-1 ;
    for (i = blkStart ; i <= blkEnd ; i++)
    { stati = getStatus(artificialStatus_,i) ;
      setStatus(artificialStatus_,keep,stati) ;
      stati = getStatus(constraintStatus_,i) ;
      setStatus(constraintStatus_,keep++,stati) ; }
    for (t++ ; t < tgtCnt-1 && tgts[t]+1 == tgts[t+1] ; t++) ;
    blkStart = tgts[t]+1 ; }
/*
  Finish off by copying from last deleted index to end of the status arrays.
*/
  for (i = blkStart ; i < numArtificial_ ; i++)
  { stati = getStatus(artificialStatus_,i) ;
    setStatus(artificialStatus_,keep,stati) ;
    stati = getStatus(constraintStatus_,i) ;
    setStatus(constraintStatus_,keep++,stati) ; }

  numArtificial_ -= tgtCnt ;
# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif


  return ; }

/*
  deleteRows takes an unordered list of target indices with duplicates and
  removes them from the basis. The strategy is to preprocess the list into
  an ordered list without duplicates, suitable for compressRows.
*/
/*!
   Removal of a tight constraint with a nonbasic logical implies that some
   basic variable must be kicked out of the basis. There's no cheap, efficient
   way to choose this variable, so the choice is left to the client.
*/
/*
  To elaborate on the above comment: When a tight constraint is removed, new
  extreme points are exposed. There's a reasonable likelihood they'll be
  desireable points (since the tight constraint was most likely tight because
  it was blocking movement in a desireable direction). In essence, we want to
  take the next primal pivot and see what comes tight. That's a fair bit of
  work, and on balance best left to the client to decide if it's appropriate,
  or if something else should be done.
*/
void ODWSB::deleteRows (int rawTgtCnt, const int *rawTgts)
{ 
/*
  Bail out if we're called with nothing to do.
*/
  if (rawTgtCnt <= 0) return ;

  int *tgts = new int[rawTgtCnt] ;
  memcpy(tgts,rawTgts,rawTgtCnt*sizeof(int)) ;
  int *first = &tgts[0] ;
  int *last = &tgts[rawTgtCnt] ;
  int *endUnique ;
  std::sort(first,last) ;
  endUnique = std::unique(first,last) ;
  ptrdiff_t tgtCnt = endUnique-first ;
  compressRows(static_cast<int>(tgtCnt),tgts) ;
  delete [] tgts ;

# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif

  return  ; }

/*
  The good news is that CWSB::deleteColumns works just fine for ODWSB.
*/

/*
  mergeBasis was originally developed to deal with expansion of a basis in
  cbc. The original coding manipulated artificialStatus_ directly, losing the
  active/inactive information in constraintStatus_. mergeBasis rephrases the
  activity in terms of merging entries from an old basis into a new, expanded
  basis. The resulting routine is capable of general merging of a source basis
  into a target (this) basis.

  This code is substantially identical to CoinWarmStartBasis::mergeBasis,
  with the exception that it understands constraintStatus_.

  If the xferRows (xferCols) vector is missing, no row (column) information
  will be transferred from src to tgt.
*/

void ODWSB::mergeBasis (const CoinWarmStartBasis *cwsb_src,
		        const XferVec *xferRows, const XferVec *xferCols)

{ assert(cwsb_src) ;
  const ODWSB *src = dynamic_cast<const ODWSB *>(cwsb_src) ;
  assert(src) ;
  int srcCols = src->getNumStructural() ;
  int srcRows = src->getNumArtificial() ;
/*
  Merge the structural variable status.
*/
  if (srcCols > 0 && xferCols != NULL)
  { XferVec::const_iterator xferSpec = xferCols->begin() ;
    XferVec::const_iterator xferEnd = xferCols->end() ;
    for ( ; xferSpec != xferEnd ; xferSpec++)
    { int srcNdx = (*xferSpec).first ;
      int tgtNdx = (*xferSpec).second ;
      int runLen = (*xferSpec).third ;
      assert(srcNdx >= 0 && srcNdx+runLen <= srcCols) ;
      assert(tgtNdx >= 0 && tgtNdx+runLen <= getNumStructural()) ;
      for (int i = 0 ; i < runLen ; i++)
      { CoinWarmStartBasis::Status stat = src->getStructStatus(srcNdx+i) ;
	setStatus(structuralStatus_,tgtNdx+i,stat) ; } } }
/*
  Merge the row (artificial variable and constraint activity) status.
*/
  if (srcRows > 0 && xferRows != NULL)
  { XferVec::const_iterator xferSpec = xferRows->begin() ;
    XferVec::const_iterator xferEnd = xferRows->end() ;
    for ( ; xferSpec != xferEnd ; xferSpec++)
    { int srcNdx = (*xferSpec).first ;
      int tgtNdx = (*xferSpec).second ;
      int runLen = (*xferSpec).third ;
#     if ODWSB_TRACK_BASIS > 0
      std::cout
        << "\tmerging from " << srcNdx
	<< " to " << tgtNdx << ", run = " << runLen
	<< "." << std::endl ;
#     endif
      assert(srcNdx >= 0 && srcNdx+runLen <= srcRows) ;
      assert(tgtNdx >= 0 && tgtNdx+runLen <= getNumArtificial()) ;
      for (int i = 0 ; i < runLen ; i++)
      { CoinWarmStartBasis::Status stat = src->getArtifStatus(srcNdx+i) ;
	setStatus(artificialStatus_,tgtNdx+i,stat) ;
        stat = src->getConStatus(srcNdx+i) ;
	setStatus(constraintStatus_,tgtNdx+i,stat) ; } } }

  return ; }

//@}

/*! \defgroup BasisInfo Methods to get and set basis information
    \brief Methods to get and set basis information
*/

//@{

/*!
  Count the number of active constraints by scanning the constraint status
  array.
*/

int ODWSB::numberActiveConstraints () const

{ int i ;
  int concnt = getNumArtificial() ;
  int actcnt = 0 ;

  for (i = 0 ; i < concnt ; i++)
    if (getStatus(constraintStatus_,i) == CWSB::atLowerBound) actcnt++ ;
  
  return (actcnt) ; }

/*! \defgroup BasisDiff Basis `diff' methods
    \brief Methods to calculate and apply a `diff' between two bases.
*/

//@{

/*!
  The capabilities are limited by the CoinWarmStartBasis format: oldBasis can
  be no larger than newBasis (the basis pointed to by \c this), and the
  subset of newBasis covered by oldBasis is assumed to contain the identical
  set of logical and structural variables, in order.

  We use CWSB::generateDiff to deal with the status arrays for the logical and
  structural variables, then add an additional vector for constraint status.
*/
CoinWarmStartDiff *ODWSB::generateDiff
  (const CoinWarmStart *const oldCWS) const
{
/*
  Make sure the parameter is an OsiDylpWarmStartBasis.
*/
  const OsiDylpWarmStartBasis *oldBasis =
      dynamic_cast<const OsiDylpWarmStartBasis *>(oldCWS) ;
  if (!oldBasis)
  { throw CoinError("Old basis not OsiDylpWarmStartBasis.",
		    "generateDiff","OsiDylpWarmStartBasis") ; }
  const OsiDylpWarmStartBasis *newBasis = this ;
# if ODSI_PARANOIA >= 2
  oldBasis->checkBasis() ;
  checkBasis() ;
# endif
/*
  Make sure newBasis is equal or bigger than oldBasis. Calculate the worst case
  number of diffs and allocate vectors to hold them.
*/
  const int oldArtifCnt = oldBasis->getNumArtificial() ;
  const int newArtifCnt = newBasis->getNumArtificial() ;

  assert(newArtifCnt >= oldArtifCnt) ;
/*
  Ok, we're good to go. Call CWSB::generateDiff to deal with the logical and
  structural arrays.
*/
  const CoinWarmStartBasisDiff *cwsbDiff =
    dynamic_cast<const CoinWarmStartBasisDiff *>(CWSB::generateDiff(oldCWS)) ;
/*
  Now generate diffs for the constraint array.
*/

  int sizeOldArtif = (oldArtifCnt+15)>>4 ;
  int sizeNewArtif = (newArtifCnt+15)>>4 ;
  int maxBasisLength = sizeNewArtif ;

  unsigned int *diffNdx = new unsigned int [maxBasisLength]; 
  unsigned int *diffVal = new unsigned int [maxBasisLength]; 
/*
  Scan the constraint status.
  For the portion of the status arrays which overlap, create
  diffs. Then add any additional status from newBasis.
*/
  const unsigned int *oldStatus =
      reinterpret_cast<const unsigned int *>(oldBasis->getConstraintStatus()) ;
  const unsigned int *newStatus = 
      reinterpret_cast<const unsigned int *>(newBasis->getConstraintStatus()) ;
  int numberChanged = 0 ;
  int i ;
  for (i = 0 ; i < sizeOldArtif ; i++)
  { if (oldStatus[i] != newStatus[i])
    { diffNdx[numberChanged] = i ;
      diffVal[numberChanged++] = newStatus[i] ; } }
  for ( ; i < sizeNewArtif ; i++)
  { diffNdx[numberChanged] = i ;
    diffVal[numberChanged++] = newStatus[i] ; }
/*
  Create the object of our desire.
*/
  OsiDylpWarmStartBasisDiff *diff =
    new OsiDylpWarmStartBasisDiff(numberChanged,diffNdx,diffVal,cwsbDiff) ;
/*
  Clean up and return.
*/
  delete[] diffNdx ;
  delete[] diffVal ;
  delete cwsbDiff ;

  return (dynamic_cast<CoinWarmStartDiff *>(diff)) ; }

/*!
   Update this basis by applying \p diff. It's assumed that the allocated
   capacity of the basis is sufficiently large.

   We use CWSB::applyDiff to deal with the logical and structural status
   vectors, then apply the diffs for the constraint status vector.
   Unfortunately, it's not really possible to verify the basis as diffs are
   applied. The typical approach is to blow out the basis to full size and
   apply diffs as we go. Intermediate stages can have inconsistencies because
   they aren't yet at full size.
*/

void ODWSB::applyDiff (const CoinWarmStartDiff *const cwsdDiff)
{
/*
  Make sure we have an OsiDylpWarmStartBasisDiff
*/
  const OsiDylpWarmStartBasisDiff *diff =
    dynamic_cast<const OsiDylpWarmStartBasisDiff *>(cwsdDiff) ;
  if (!diff)
  { throw CoinError("Diff not OsiDylpWarmStartBasisDiff.",
		    "applyDiff","OsiDylpWarmStartBasis") ; }
/*
  Call CWSB::applyDiff to deal with the logical and structural status.
*/
  CWSB::applyDiff(cwsdDiff) ;
/*
  Now fix up the constraint status array. Application of the diff is by
  straighforward replacement of words in the status array.
*/
  const int numberChanges = diff->consze_ ;
  const unsigned int *diffNdxs = diff->condiffNdxs_ ;
  const unsigned int *diffVals = diff->condiffVals_ ;
  unsigned int *constraintStatus =
      reinterpret_cast<unsigned int *>(this->getConstraintStatus()) ;

  for (int i = 0 ; i < numberChanges ; i++)
  { unsigned int diffNdx = diffNdxs[i] ;
    unsigned int diffVal = diffVals[i] ;
    constraintStatus[diffNdx] = diffVal ; }

  return ; }

//@}


/*! \defgroup MiscUtil Miscellaneous Utilities
    \brief Miscellaneous utility functions
*/

//@{

/*!
  Print the warm start object in a (more or less) human-readable form.
  Intended for debugging.
*/

void ODWSB::print () const

{ char conlett[] = {'I','?','?','A'} ;
  char statlett[] = {'F','B','U','L'} ;
  int i,basic_logicals,basic_structurals ;

  std::cout << "ODWSB: " ;
  std::cout << getNumArtificial() << " constraints (" <<
	       numberActiveConstraints() << " active), " ;
  std::cout << getNumStructural() << " variables." << std::endl ;

  std::cout << "Rows: " ;
  for (i = 0 ; i < getNumArtificial() ; i++)
  { std::cout << conlett[getConStatus(i)] ; }
  std::cout << std::endl ;

  std::cout << "      " ;
  basic_logicals = 0 ;
  for (i = 0 ; i < getNumArtificial() ; i++)
  { std::cout << statlett[getArtifStatus(i)] ;
    if (getArtifStatus(i) == CWSB::basic) basic_logicals++ ; }
  std::cout << std::endl ;
  
  std::cout << "Cols: " ;
  basic_structurals = 0 ;
  for (i = 0 ; i < getNumStructural() ; i++)
  { std::cout << statlett[getStructStatus(i)] ;
    if (getStructStatus(i) == CWSB::basic) basic_structurals++ ; }

  std::cout << std::endl << "	basic: ("
	    << basic_structurals << " + " << basic_logicals << ")" ;
  std::cout << std::endl ;

# if ODSI_PARANOIA >= 2
  checkBasis() ;
# endif
  
  return ; }

/*!
  Check the basis to make sure it's properly formed. The convention adopted
  for inactive constraints in an ODWSB is that the logical should be basic.
  After subtracting the basic logicals associated with inactive constraints,
  there should be exactly enough basic variables for the active constraints.
*/

void ODWSB::checkBasis (CoinMessageHandler* msghandler) const

{ int i ;
  bool retval = true ;
  int numBasicStruct,numBasicLog,numCons,numActCons ;
  Status conStat,logStat ;

  numBasicStruct = numberBasicStructurals() ;
  numBasicLog = 0 ;
  numCons = getNumArtificial() ;
  numActCons = numberActiveConstraints() ;
/*
  Scan the constraint status vector. Check that the logical associated with
  an inactive constraint is basic.  Count the number of basic logicals
  associated with active constraints --- these will be part of dylp's basis.

  The notion that the logical associated with an inactive constraint should be
  basic is a convention adopted by ODWSB when it must synthesize a full basis
  for use by COIN. Dylp simply doesn't see the problem --- the constraint is
  inactive and does not require a basic variable. If the logical is not basic,
  it indicates a logical error in the code.
*/
  for (i = 0 ; i < numCons ; i++)
  { conStat = getConStatus(i) ;
    logStat = getArtifStatus(i) ;
    if (conStat == CWSB::isFree)
    { if (logStat != CWSB::basic)
      { if (msghandler)
		*msghandler << "Basis error! Logical for inactive constraint " << i
		  << " is nonbasic." << CoinMessageEol ;
	retval = false ; } }
    else
    if (conStat == CWSB::atLowerBound)
    { if (logStat == CWSB::basic)
      { numBasicLog++ ; } }
    else
    { 
      if (msghandler)
		*msghandler << "Basis error! Status of constraint " << i
			<< " is " << conStat << ". Should be isFree or atLowerBound."
			<< CoinMessageEol ;
      retval = false ; } }
/*
  The number of basic variables (basic structural, plus basic logicals
  associated with active constraints) should equal the number of active
  constraints. ODSI can easily cope with too few basic variables, and it will
  happen on occasion, depending on how the client code implements fixing of
  basic variables. ODSI can't deal with too many basic variables (in general,
  there's no guarantee we can find a basic variable that's at bound).
*/
  if (numBasicStruct+numBasicLog != numActCons)
  { if (numBasicStruct+numBasicLog < numActCons)
    { if (msghandler) *msghandler << "Basis warning! " ; }
    else
    { if (msghandler) *msghandler << "Basis error! " ;
      retval = false ; }
    if (msghandler)
    	*msghandler << numActCons << " active constraints but ("
	      << numBasicStruct << "+" << numBasicLog
	      << ") basic variables." << CoinMessageEol ; }

  if (retval == false)
  { if (msghandler) *msghandler << "Basis consistency check failed!" << CoinMessageEol ; }
# if ODSI_PARANOIA >= 3
  else
  { if (msghandler) *msghanlder << "Basis consistency check passed!" << CoinMessageEol ; }
# endif
  
  return ; }


//@}




/* Routines for OsiDylpWarmStartBasisDiff */

/*
  Constructor given constraint diff data and a pointer to a
  CoinWarmStartBasisDiff object.
*/
OsiDylpWarmStartBasisDiff::OsiDylpWarmStartBasisDiff (int sze,
  const unsigned int *const diffNdxs, const unsigned int *const diffVals,
  const CoinWarmStartBasisDiff *const cwsbd)

  : CoinWarmStartBasisDiff(*cwsbd),
    consze_(sze),
    condiffNdxs_(0),
    condiffVals_(0)

{ if (sze > 0)
  { condiffNdxs_ = new unsigned int[sze] ;
    memcpy(condiffNdxs_,diffNdxs,sze*sizeof(unsigned int)) ;
    condiffVals_ = new unsigned int[sze] ;
    memcpy(condiffVals_,diffVals,sze*sizeof(unsigned int)) ; }
  
  return ; }

/*
  Copy constructor
*/
OsiDylpWarmStartBasisDiff::OsiDylpWarmStartBasisDiff
  (const OsiDylpWarmStartBasisDiff &odwsbd)
  : CoinWarmStartBasisDiff(odwsbd),
    consze_(odwsbd.consze_),
    condiffNdxs_(0),
    condiffVals_(0)
{ if (odwsbd.consze_ > 0)
  { condiffNdxs_ = new unsigned int[odwsbd.consze_] ;
    memcpy(condiffNdxs_,odwsbd.condiffNdxs_,
	   odwsbd.consze_*sizeof(unsigned int)) ;
    condiffVals_ = new unsigned int[odwsbd.consze_] ;
    memcpy(condiffVals_,odwsbd.condiffVals_,
	   odwsbd.consze_*sizeof(unsigned int)) ; }
  
  return ; }

/*
  Assignment --- for convenience when assigning objects containing
  CoinWarmStartBasisDiff objects.
*/
OsiDylpWarmStartBasisDiff&
OsiDylpWarmStartBasisDiff::operator= (const OsiDylpWarmStartBasisDiff &rhs)

{ if (this != &rhs)
  { CoinWarmStartBasisDiff::operator=(rhs) ;
    if (consze_ > 0)
    { delete[] condiffNdxs_ ;
      delete[] condiffVals_ ; }
    consze_ = rhs.consze_ ;
    if (consze_ > 0)
    { condiffNdxs_ = new unsigned int[consze_] ;
      memcpy(condiffNdxs_,rhs.condiffNdxs_,consze_*sizeof(unsigned int)) ;
      condiffVals_ = new unsigned int[consze_] ;
      memcpy(condiffVals_,rhs.condiffVals_,consze_*sizeof(unsigned int)) ; }
    else
    { condiffNdxs_ = 0 ;
      condiffVals_ = 0 ; } }
  
  return (*this) ; }

