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Added some utility methods (swapping of columns and rows, matrix-vector multiplication)

This commit is contained in:
Paolo Cignoni 2006-04-29 10:26:04 +00:00
parent 26ce24dec3
commit 10c513dad8
1 changed files with 68 additions and 9 deletions
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77
vcg/math/matrix.h
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@ -22,6 +22,9 @@
****************************************************************************/
/***************************************************************************
$Log: not supported by cvs2svn $
Revision 1.6 2006/04/11 08:09:35 zifnab1974
changes necessary for gcc 3.4.5 on linux 64bit. Please take note of case-sensitivity of filenames
Revision 1.5 2005/12/12 11:25:00 ganovelli
added diagonal matrix, outer produce and namespace
@ -95,10 +98,12 @@ namespace vcg{
{
_rows = m;
_columns = n;
_data = new ScalarType[m*n];
unsigned int i;
for (i=0; i<_rows*_columns; i++)
_data[i] = values[i];
unsigned int dim = m*n;
_data = new ScalarType[dim];
memcpy(_data, values, dim*sizeof(ScalarType));
//unsigned int i;
//for (i=0; i<_rows*_columns; i++)
// _data[i] = values[i];
};
/*!
@ -275,7 +280,7 @@ namespace vcg{
/*!
* Get the <I>j</I>-th column on the matrix.
* \param j the column index.
* \return the reference to the column elements.
* \return the reference to the column elements. This pointer must be deallocated by the caller.
*/
TYPE* GetColumn(const unsigned int j)
{
@ -290,7 +295,7 @@ namespace vcg{
/*!
* Get the <I>i</I>-th row on the matrix.
* \param i the column index.
* \return the reference to the row elements.
* \return the reference to the row elements. This pointer must be deallocated by the caller.
*/
TYPE* GetRow(const unsigned int i)
{
@ -302,6 +307,40 @@ namespace vcg{
return v;
};
/*!
* Swaps the values of the elements between the <I>i</I>-th and the <I>j</I>-th column.
* \param i the index of the first column
* \param j the index of the second column
*/
void SwapColumns(const unsigned int i, const unsigned int j)
{
assert(0<=i && i<_columns);
assert(0<=j && j<_columns);
if (i==j)
return;
unsigned int r, e0, e1;
for (r=0, e0=i, e1=j; r<_rows; r++, e0+=_columns, e1+=_columns)
std::swap(_data[e0], _data[e1]);
};
/*!
* Swaps the values of the elements between the <I>i</I>-th and the <I>j</I>-th row.
* \param i the index of the first row
* \param j the index of the second row
*/
void SwapRows(const unsigned int i, const unsigned int j)
{
assert(0<=i && i<_rows);
assert(0<=j && j<_rows);
if (i==j)
return;
unsigned int r, e0, e1;
for (r=0, e0=i*_columns, e1=j*_columns; r<_columns; r++, e0++, e1++)
std::swap(_data[e0], _data[e1]);
};
/*!
* Assignment operator
* \param m ...
@ -397,7 +436,7 @@ namespace vcg{
/*!
* Matrix multiplication: calculates the cross product.
* \param reference to the matrix to multiply by
* \param m reference to the matrix to multiply by
* \return the matrix product
*/
Matrix<TYPE> operator*(const Matrix<TYPE> &m)
@ -418,6 +457,23 @@ namespace vcg{
};
/*!
* Matrix-Vector product. Computes the product of the matrix by the vector v.
* \param v reference to the vector to multiply by
* \return the matrix-vector product. This pointer must be deallocated by the caller
*/
ScalarType* operator*(const ScalarType v[])
{
ScalarType *result = new ScalarType[_rows];
memset(result, 0, _rows*sizeof(ScalarType));
unsigned int r, c, i;
for (r=0, i=0; r<_rows; r++)
for (c=0; c<_columns; c++, i++)
result[r] += _data[i]*v[c];
return result;
};
/*!
* Matrix multiplication: calculates the cross product.
* \param reference to the matrix to multiply by
* \return the matrix product
@ -565,7 +621,7 @@ namespace vcg{
{
assert(j>=0 && j<_columns);
unsigned int i, p;
for (i=0, p=0; i<_rows; i++, p+=_columns)
for (i=0, p=j; i<_rows; i++, p+=_columns)
_data[p] = v[i];
};
@ -638,7 +694,7 @@ namespace vcg{
{
printf("[\t");
for (j=0; j<_columns; j++)
printf("%g\t", _data[p+j]);
printf("%f\t", _data[p+j]);
printf("]\n");
}
@ -656,6 +712,9 @@ namespace vcg{
ScalarType *_data;
};
typedef vcg::ndim::Matrix<double> MatrixMNd;
typedef vcg::ndim::Matrix<float> MatrixMNf;
/*! @} */
template <class MatrixType>