devtools/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2026-04-10 11:34:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

backport improvement in 4x4 inverse precisio, and rigorous precision test

Browse Source
This commit is contained in:
Benoit Jacob
2009-11-23 10:27:10 -05:00
parent 70af59c455
commit fc7f39980c
3 changed files with 110 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
Eigen/src/LU/Inverse.h
View File

@@ -133,8 +133,11 @@ void ei_compute_inverse_in_size4_case(const MatrixType& _matrix, MatrixType* res
int good_row0, good_row1, good_i;
Matrix<RealScalar,6,1> absdet;
// any 2x2 block with determinant above this threshold will be considered good enough
RealScalar d = (matrix.col(0).squaredNorm()+matrix.col(1).squaredNorm()) * RealScalar(1e-2);
// any 2x2 block with determinant above this threshold will be considered good enough.
// The magic value 1e-1 here comes from experimentation. The bigger it is, the higher the precision,
// the slower the computation. This value 1e-1 gives precision almost as good as the brutal cofactors
// algorithm, both in average and in worst-case precision.
RealScalar d = (matrix.col(0).squaredNorm()+matrix.col(1).squaredNorm()) * RealScalar(1e-1);
#define ei_inv_size4_helper_macro(i,row0,row1) \
absdet[i] = ei_abs(matrix.coeff(row0,0)*matrix.coeff(row1,1) \
- matrix.coeff(row0,1)*matrix.coeff(row1,0)); \