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4x4 inverse:

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* change block selection threshold from 1e-2 to 1e-1
* add rigorous precision test
This commit is contained in:
Benoit Jacob
2009-11-23 10:13:21 -05:00
parent 06f11f3379
commit 44d0d667cd
5 changed files with 100 additions and 14 deletions
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7
Eigen/src/LU/Inverse.h
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@@ -235,8 +235,11 @@ struct ei_compute_inverse<MatrixType, ResultType, 4>
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)); \