Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
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//========= Copyright Valve Corporation, All rights reserved. ============//
//
//===========================================================================//
#include "tier1/sparsematrix.h"
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
void CSparseMatrix::AdjustAllRowIndicesAfter( int nStartRow, int nDelta )
{
// now, we need to offset the starting position of all subsequent rows by -1 to compensate for the removal of this element
for( int nOtherRow = nStartRow + 1 ; nOtherRow < Height(); nOtherRow++ )
{
m_rowDescriptors[nOtherRow].m_nDataIndex += nDelta;
}
}
void CSparseMatrix::SetDimensions( int nNumRows, int nNumCols )
{
m_nNumRows = nNumRows;
m_nNumCols = nNumCols;
m_entries.SetCount( 0 );
m_rowDescriptors.SetCount( m_nNumRows );
// and set all rows to be empty
for( int i = 0; i < m_nNumRows; i++ )
{
m_rowDescriptors[i].m_nNonZeroCount = 0;
m_rowDescriptors[i].m_nDataIndex = 0;
}
m_nHighestRowAppendedTo = -1;
}
void CSparseMatrix::SetElement( int nRow, int nCol, float flValue )
{
Assert( nCol < m_nNumCols );
int nCount = m_rowDescriptors[nRow].m_nNonZeroCount;
bool bValueIsZero = ( flValue == 0.0 );
int nFirstEntryIndex = m_rowDescriptors[nRow].m_nDataIndex;
if ( nCount )
{
NonZeroValueDescriptor_t *pValue = &( m_entries[nFirstEntryIndex] );
int i;
for( i = 0; i < nCount; i++ )
{
int nIdx = pValue->m_nColumnNumber;
if ( nIdx == nCol ) // we found it!
{
if ( !bValueIsZero )
{
// we want to overwrite the existing value
pValue->m_flValue = flValue;
}
else
{
// there is a non-zero element currently at this position. We need to remove it
// and we need to remove its storage.
m_rowDescriptors[nRow].m_nNonZeroCount--;
m_entries.Remove( nFirstEntryIndex + i );
// now, we need to offset the starting position of all subsequent rows by -1 to compensate for the removal of this element
AdjustAllRowIndicesAfter( nRow, -1 );
}
return;
}
if ( nIdx > nCol )
{
break;
}
pValue++;
}
// we did not find an entry for this cell. If we were writing zero, fine - we are
// done, otherwise insert
if (! bValueIsZero )
{
m_rowDescriptors[nRow].m_nNonZeroCount++;
NonZeroValueDescriptor_t newValue;
newValue.m_nColumnNumber = nCol;
newValue.m_flValue = flValue;
if ( i == nCount ) // need to append
{
m_entries.InsertAfter( nFirstEntryIndex + nCount - 1, newValue );
}
else
{
m_entries.InsertBefore( nFirstEntryIndex + i, newValue );
}
// now, we need to offset the starting position of all subsequent rows by -1 to compensate for the addition of this element
AdjustAllRowIndicesAfter( nRow, +1 );
}
}
else
{
// row is empty. We may need to insert
if ( ! bValueIsZero )
{
m_rowDescriptors[nRow].m_nNonZeroCount++;
NonZeroValueDescriptor_t newValue;
newValue.m_nColumnNumber = nCol;
newValue.m_flValue = flValue;
m_entries.InsertBefore( nFirstEntryIndex, newValue );
AdjustAllRowIndicesAfter( nRow, +1 );
}
}
}
void CSparseMatrix::FinishedAppending( void )
{
// set all pointers to space for subsequent rows to the right value
for( int i = m_nHighestRowAppendedTo + 1 ; i < Height(); i++ )
{
m_rowDescriptors[i].m_nDataIndex = m_entries.Count();
}
}
void CSparseMatrix::AppendElement( int nRow, int nColumn, float flValue )
{
if ( flValue != 0.0 )
{
if ( m_nHighestRowAppendedTo != nRow )
{
Assert( nRow > m_nHighestRowAppendedTo );
for( int i = m_nHighestRowAppendedTo + 1; i <= nRow; i++ )
{
m_rowDescriptors[i].m_nDataIndex = m_entries.Count();
}
}
m_nHighestRowAppendedTo = nRow;
m_rowDescriptors[nRow].m_nNonZeroCount++;
NonZeroValueDescriptor_t newDesc;
newDesc.m_nColumnNumber = nColumn;
newDesc.m_flValue = flValue;
m_entries.AddToTail( newDesc );
}
}