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* Add fixed-size template versions of corner(), start(), end().

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* Use them to write an unrolled path in echelon.cpp, as an
  experiment before I do this LU module.
* For floating-point types, make ei_random() use an amplitude
  of 1.
This commit is contained in:
Benoit Jacob
2008-04-12 17:37:27 +00:00
parent dcebc46cdc
commit ab4046970b
8 changed files with 272 additions and 47 deletions
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67
doc/echelon.cpp
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@@ -4,21 +4,72 @@ USING_PART_OF_NAMESPACE_EIGEN
namespace Eigen {
template<typename Derived>
void echelon(MatrixBase<Derived>& m)
/* Echelon a matrix in-place:
*
* Meta-Unrolled version, for small fixed-size matrices
*/
template<typename Derived, int Step>
struct unroll_echelon
{
for(int k = 0; k < m.diagonal().size(); k++)
enum { k = Step - 1,
Rows = Derived::RowsAtCompileTime,
Cols = Derived::ColsAtCompileTime,
CornerRows = Rows - k,
CornerCols = Cols - k
};
static void run(MatrixBase<Derived>& m)
{
unroll_echelon<Derived, Step-1>::run(m);
int rowOfBiggest, colOfBiggest;
int cornerRows = m.rows()-k, cornerCols = m.cols()-k;
m.corner(BottomRight, cornerRows, cornerCols)
m.template corner<CornerRows, CornerCols>(BottomRight)
.cwiseAbs()
.maxCoeff(&rowOfBiggest, &colOfBiggest);
m.row(k).swap(m.row(k+rowOfBiggest));
m.col(k).swap(m.col(k+colOfBiggest));
m.corner(BottomRight, cornerRows-1, cornerCols)
-= m.col(k).end(cornerRows-1) * (m.row(k).end(cornerCols) / m(k,k));
m.template corner<CornerRows-1, CornerCols>(BottomRight)
-= m.col(k).template end<CornerRows-1>()
* (m.row(k).template end<CornerCols>() / m(k,k));
}
};
template<typename Derived>
struct unroll_echelon<Derived, 0>
{
static void run(MatrixBase<Derived>& m) {}
};
/* Echelon a matrix in-place:
*
* Non-unrolled version, for dynamic-size matrices.
* (this version works for all matrices, but in the fixed-size case the other
* version is faster).
*/
template<typename Derived>
struct unroll_echelon<Derived, Dynamic>
{
static void run(MatrixBase<Derived>& m)
{
for(int k = 0; k < m.diagonal().size(); k++)
{
int rowOfBiggest, colOfBiggest;
int cornerRows = m.rows()-k, cornerCols = m.cols()-k;
m.corner(BottomRight, cornerRows, cornerCols)
.cwiseAbs()
.maxCoeff(&rowOfBiggest, &colOfBiggest);
m.row(k).swap(m.row(k+rowOfBiggest));
m.col(k).swap(m.col(k+colOfBiggest));
m.corner(BottomRight, cornerRows-1, cornerCols)
-= m.col(k).end(cornerRows-1) * (m.row(k).end(cornerCols) / m(k,k));
}
}
};
using namespace std;
template<typename Derived>
void echelon(MatrixBase<Derived>& m)
{
const int size = DiagonalCoeffs<Derived>::SizeAtCompileTime;
const bool unroll = size <= 4;
unroll_echelon<Derived, unroll ? size : Dynamic>::run(m);
}
template<typename Derived>
@@ -49,7 +100,7 @@ using namespace std;
int main(int, char **)
{
srand((unsigned int)time(0));
const int Rows = 6, Cols = 4;
const int Rows = 6, Cols = 6;
typedef Matrix<double, Rows, Cols> Mat;
const int N = Rows < Cols ? Rows : Cols;