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Added enum for the sorting strategy of the result in SVD.

This commit is contained in:
Paolo Cignoni 2006-05-15 07:36:50 +00:00
parent 3c222fd583
commit 179d96b098
1 changed files with 31 additions and 20 deletions
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51
vcg/math/lin_algebra.h
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@ -138,6 +138,11 @@ namespace vcg
return (sqr_arg == 0 ? 0 : sqr_arg*sqr_arg); return (sqr_arg == 0 ? 0 : sqr_arg*sqr_arg);
} }
/*!
*
*/
enum SortingStrategy {LeaveUnsorted=0, SortAscending=1, SortDescending=2};
/*! /*!
* Given a matrix <I>A<SUB>m×n</SUB></I>, this routine computes its singular value decomposition, * Given a matrix <I>A<SUB>m×n</SUB></I>, this routine computes its singular value decomposition,
@ -150,7 +155,7 @@ namespace vcg
* \return * \return
*/ */
template <typename MATRIX_TYPE> template <typename MATRIX_TYPE>
static bool SingularValueDecomposition(MATRIX_TYPE &A, typename MATRIX_TYPE::ScalarType *W, MATRIX_TYPE &V, const bool sort_w=false, const int max_iters=30) static bool SingularValueDecomposition(MATRIX_TYPE &A, typename MATRIX_TYPE::ScalarType *W, MATRIX_TYPE &V, const SortingStrategy sorting=LeaveUnsorted, const int max_iters=30)
{ {
typedef typename MATRIX_TYPE::ScalarType ScalarType; typedef typename MATRIX_TYPE::ScalarType ScalarType;
int m = (int) A.RowsNumber(); int m = (int) A.RowsNumber();
@ -395,8 +400,8 @@ namespace vcg
} }
delete []rv1; delete []rv1;
if (sort_w) if (sorting!=LeaveUnsorted)
Sort<MATRIX_TYPE>(A, W, V, false); Sort<MATRIX_TYPE>(A, W, V, sorting);
return convergence; return convergence;
}; };
@ -406,8 +411,9 @@ namespace vcg
* Sort the singular values computed by the <CODE>SingularValueDecomposition</CODE> procedure and * Sort the singular values computed by the <CODE>SingularValueDecomposition</CODE> procedure and
* modify the matrices <I>U</I> and <I>V</I> accordingly. * modify the matrices <I>U</I> and <I>V</I> accordingly.
*/ */
// TODO modify the last parameter type
template< typename MATRIX_TYPE > template< typename MATRIX_TYPE >
void Sort(MATRIX_TYPE &U, typename MATRIX_TYPE::ScalarType W[], MATRIX_TYPE &V, bool ascending) void Sort(MATRIX_TYPE &U, typename MATRIX_TYPE::ScalarType W[], MATRIX_TYPE &V, const SortingStrategy sorting)
{ {
typedef typename MATRIX_TYPE::ScalarType ScalarType; typedef typename MATRIX_TYPE::ScalarType ScalarType;
@ -424,26 +430,31 @@ namespace vcg
{ {
int k = i; int k = i;
ScalarType p = W[i]; ScalarType p = W[i];
if (ascending) switch (sorting)
{ {
for (int j=i+1; j<n; j++) case SortAscending:
{ {
if (W[j] < p) for (int j=i+1; j<n; j++)
{ {
k = j; if (W[j] < p)
p = W[j]; {
} k = j;
p = W[j];
}
}
break;
} }
} case SortDescending:
else {
{ for (int j=i+1; j<n; j++)
for (int j=i+1; j<n; j++)
{
if (W[j] > p)
{ {
k = j; if (W[j] > p)
p = W[j]; {
} k = j;
p = W[j];
}
}
break;
} }
} }
if (k != i) if (k != i)