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-rw-r--r--Eigen/src/Core/MatrixBase.h9
-rw-r--r--Eigen/src/LU/Inverse.h418
-rw-r--r--test/inverse.cpp15
3 files changed, 243 insertions, 199 deletions
diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index cccb23241..24b3feb6f 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -703,9 +703,12 @@ template<typename Derived> class MatrixBase
const PartialLU<PlainMatrixType> partialLu() const;
const PlainMatrixType inverse() const;
template<typename ResultType>
- void computeInverse(ResultType *result) const;
- template<typename ResultType>
- bool computeInverseWithCheck(ResultType *result ) const;
+ void computeInverseAndDetWithCheck(
+ ResultType& inverse,
+ typename ResultType::Scalar& determinant,
+ bool& invertible,
+ const RealScalar& absDeterminantThreshold = precision<Scalar>()
+ ) const;
Scalar determinant() const;
/////////// Cholesky module ///////////
diff --git a/Eigen/src/LU/Inverse.h b/Eigen/src/LU/Inverse.h
index b4e10b023..87fb721e6 100644
--- a/Eigen/src/LU/Inverse.h
+++ b/Eigen/src/LU/Inverse.h
@@ -1,7 +1,7 @@
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
-// Copyright (C) 2008 Benoit Jacob <jacob.benoit.1@gmail.com>
+// Copyright (C) 2008-2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
@@ -29,74 +29,96 @@
*** Part 1 : optimized implementations for fixed-size 2,3,4 cases ***
********************************************************************/
-template<typename XprType, typename MatrixType>
+template<typename MatrixType, typename ResultType>
inline void ei_compute_inverse_size2_helper(
- const XprType& matrix, const typename MatrixType::Scalar& invdet,
- MatrixType* result)
+ const MatrixType& matrix, const typename ResultType::Scalar& invdet,
+ ResultType& result)
{
- result->coeffRef(0,0) = matrix.coeff(1,1) * invdet;
- result->coeffRef(1,0) = -matrix.coeff(1,0) * invdet;
- result->coeffRef(0,1) = -matrix.coeff(0,1) * invdet;
- result->coeffRef(1,1) = matrix.coeff(0,0) * invdet;
+ result.coeffRef(0,0) = matrix.coeff(1,1) * invdet;
+ result.coeffRef(1,0) = -matrix.coeff(1,0) * invdet;
+ result.coeffRef(0,1) = -matrix.coeff(0,1) * invdet;
+ result.coeffRef(1,1) = matrix.coeff(0,0) * invdet;
}
-template<typename MatrixType>
-inline void ei_compute_inverse_size2(const MatrixType& matrix, MatrixType* result)
+template<typename MatrixType, typename ResultType>
+inline void ei_compute_inverse_size2(const MatrixType& matrix, ResultType& result)
{
- typedef typename MatrixType::Scalar Scalar;
- const Scalar invdet = Scalar(1) / matrix.determinant();
- ei_compute_inverse_size2_helper( matrix, invdet, result );
+ typedef typename ResultType::Scalar Scalar;
+ const Scalar invdet = typename MatrixType::Scalar(1) / matrix.determinant();
+ ei_compute_inverse_size2_helper(matrix, invdet, result);
}
-template<typename XprType, typename MatrixType>
-bool ei_compute_inverse_size2_with_check(const XprType& matrix, MatrixType* result)
+template<typename MatrixType, typename ResultType>
+inline void ei_compute_inverse_and_det_size2_with_check(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& inverse,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
{
- typedef typename MatrixType::Scalar Scalar;
- const Scalar det = matrix.determinant();
- if(ei_isMuchSmallerThan(det, matrix.cwise().abs().maxCoeff())) return false;
- const Scalar invdet = Scalar(1) / det;
- ei_compute_inverse_size2_helper( matrix, invdet, result );
- return true;
+ typedef typename ResultType::Scalar Scalar;
+ determinant = matrix.determinant();
+ invertible = ei_abs(determinant) > absDeterminantThreshold;
+ if(!invertible) return;
+ const Scalar invdet = Scalar(1) / determinant;
+ ei_compute_inverse_size2_helper(matrix, invdet, inverse);
}
-template<typename XprType, typename MatrixType>
+template<typename MatrixType, typename ResultType>
void ei_compute_inverse_size3_helper(
- const XprType& matrix,
- const typename MatrixType::Scalar& invdet,
- const typename MatrixType::Scalar& det_minor00,
- const typename MatrixType::Scalar& det_minor10,
- const typename MatrixType::Scalar& det_minor20,
- MatrixType* result)
+ const MatrixType& matrix,
+ const typename ResultType::Scalar& invdet,
+ const Matrix<typename ResultType::Scalar,3,1>& cofactors_col0,
+ ResultType& result)
{
- result->coeffRef(0, 0) = det_minor00 * invdet;
- result->coeffRef(0, 1) = -det_minor10 * invdet;
- result->coeffRef(0, 2) = det_minor20 * invdet;
- result->coeffRef(1, 0) = -matrix.minor(0,1).determinant() * invdet;
- result->coeffRef(1, 1) = matrix.minor(1,1).determinant() * invdet;
- result->coeffRef(1, 2) = -matrix.minor(2,1).determinant() * invdet;
- result->coeffRef(2, 0) = matrix.minor(0,2).determinant() * invdet;
- result->coeffRef(2, 1) = -matrix.minor(1,2).determinant() * invdet;
- result->coeffRef(2, 2) = matrix.minor(2,2).determinant() * invdet;
+ result.row(0) = cofactors_col0 * invdet;
+ result.coeffRef(1,0) = -matrix.minor(0,1).determinant() * invdet;
+ result.coeffRef(1,1) = matrix.minor(1,1).determinant() * invdet;
+ result.coeffRef(1,2) = -matrix.minor(2,1).determinant() * invdet;
+ result.coeffRef(2,0) = matrix.minor(0,2).determinant() * invdet;
+ result.coeffRef(2,1) = -matrix.minor(1,2).determinant() * invdet;
+ result.coeffRef(2,2) = matrix.minor(2,2).determinant() * invdet;
}
-template<bool Check, typename XprType, typename MatrixType>
-bool ei_compute_inverse_size3(const XprType& matrix, MatrixType* result)
+template<typename MatrixType, typename ResultType>
+void ei_compute_inverse_size3(
+ const MatrixType& matrix,
+ ResultType& result)
{
- typedef typename MatrixType::Scalar Scalar;
- const Scalar det_minor00 = matrix.minor(0,0).determinant();
- const Scalar det_minor10 = matrix.minor(1,0).determinant();
- const Scalar det_minor20 = matrix.minor(2,0).determinant();
- const Scalar det = ( det_minor00 * matrix.coeff(0,0)
- - det_minor10 * matrix.coeff(1,0)
- + det_minor20 * matrix.coeff(2,0) );
- if(Check) if(ei_isMuchSmallerThan(det, matrix.cwise().abs().maxCoeff())) return false;
+ typedef typename ResultType::Scalar Scalar;
+ Matrix<Scalar,3,1> cofactors_col0;
+ cofactors_col0.coeffRef(0) = matrix.minor(0,0).determinant();
+ cofactors_col0.coeffRef(1) = -matrix.minor(1,0).determinant();
+ cofactors_col0.coeffRef(2) = matrix.minor(2,0).determinant();
+ const Scalar det = (cofactors_col0.cwise()*matrix.col(0)).sum();
const Scalar invdet = Scalar(1) / det;
- ei_compute_inverse_size3_helper( matrix, invdet, det_minor00, det_minor10, det_minor20, result );
- return true;
+ ei_compute_inverse_size3_helper(matrix, invdet, cofactors_col0, result);
}
template<typename MatrixType, typename ResultType>
-bool ei_compute_inverse_size4_helper(const MatrixType& matrix, ResultType* result)
+void ei_compute_inverse_and_det_size3_with_check(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& inverse,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
+{
+ typedef typename ResultType::Scalar Scalar;
+ Matrix<Scalar,3,1> cofactors_col0;
+ cofactors_col0.coeffRef(0) = matrix.minor(0,0).determinant();
+ cofactors_col0.coeffRef(1) = -matrix.minor(1,0).determinant();
+ cofactors_col0.coeffRef(2) = matrix.minor(2,0).determinant();
+ determinant = (cofactors_col0.cwise()*matrix.col(0)).sum();
+ invertible = ei_abs(determinant) > absDeterminantThreshold;
+ if(!invertible) return;
+ const Scalar invdet = Scalar(1) / determinant;
+ ei_compute_inverse_size3_helper(matrix, invdet, cofactors_col0, inverse);
+}
+
+template<typename MatrixType, typename ResultType>
+void ei_compute_inverse_size4_helper(const MatrixType& matrix, ResultType& result)
{
/* Let's split M into four 2x2 blocks:
* (P Q)
@@ -111,113 +133,106 @@ bool ei_compute_inverse_size4_helper(const MatrixType& matrix, ResultType* resul
* Q' = -(P_inverse*Q) * S'
* R' = -S' * (R*P_inverse)
*/
- typedef Block<MatrixType,2,2> XprBlock22;
+ typedef Block<ResultType,2,2> XprBlock22;
typedef typename MatrixBase<XprBlock22>::PlainMatrixType Block22;
Block22 P_inverse;
- if(ei_compute_inverse_size2_with_check(matrix.template block<2,2>(0,0), &P_inverse))
- {
- const Block22 Q = matrix.template block<2,2>(0,2);
- const Block22 P_inverse_times_Q = P_inverse * Q;
- const XprBlock22 R = matrix.template block<2,2>(2,0);
- const Block22 R_times_P_inverse = R * P_inverse;
- const Block22 R_times_P_inverse_times_Q = R_times_P_inverse * Q;
- const XprBlock22 S = matrix.template block<2,2>(2,2);
- const Block22 X = S - R_times_P_inverse_times_Q;
- Block22 Y;
- ei_compute_inverse_size2(X, &Y);
- result->template block<2,2>(2,2) = Y;
- result->template block<2,2>(2,0) = - Y * R_times_P_inverse;
- const Block22 Z = P_inverse_times_Q * Y;
- result->template block<2,2>(0,2) = - Z;
- result->template block<2,2>(0,0) = P_inverse + Z * R_times_P_inverse;
- return true;
- }
- else
- {
- return false;
- }
+ ei_compute_inverse_size2(matrix.template block<2,2>(0,0), P_inverse);
+ const Block22 Q = matrix.template block<2,2>(0,2);
+ const Block22 P_inverse_times_Q = P_inverse * Q;
+ const XprBlock22 R = matrix.template block<2,2>(2,0);
+ const Block22 R_times_P_inverse = R * P_inverse;
+ const Block22 R_times_P_inverse_times_Q = R_times_P_inverse * Q;
+ const XprBlock22 S = matrix.template block<2,2>(2,2);
+ const Block22 X = S - R_times_P_inverse_times_Q;
+ Block22 Y;
+ ei_compute_inverse_size2(X, Y);
+ result.template block<2,2>(2,2) = Y;
+ result.template block<2,2>(2,0) = - Y * R_times_P_inverse;
+ const Block22 Z = P_inverse_times_Q * Y;
+ result.template block<2,2>(0,2) = - Z;
+ result.template block<2,2>(0,0) = P_inverse + Z * R_times_P_inverse;
}
-template<typename XprType, typename MatrixType>
-bool ei_compute_inverse_size4_with_check(const XprType& matrix, MatrixType* result)
+template<typename MatrixType, typename ResultType>
+void ei_compute_inverse_size4(const MatrixType& _matrix, ResultType& result)
{
- if(ei_compute_inverse_size4_helper(matrix, result))
- {
- // good ! The topleft 2x2 block was invertible, so the 2x2 blocks approach is successful.
- return true;
- }
- else
- {
- // rare case: the topleft 2x2 block is not invertible (but the matrix itself is assumed to be).
- // since this is a rare case, we don't need to optimize it. We just want to handle it with little
- // additional code.
- MatrixType m(matrix);
- m.row(0).swap(m.row(2));
- m.row(1).swap(m.row(3));
- if(ei_compute_inverse_size4_helper(m, result))
- {
- // good, the topleft 2x2 block of m is invertible. Since m is different from matrix in that some
- // rows were permuted, the actual inverse of matrix is derived from the inverse of m by permuting
- // the corresponding columns.
- result->col(0).swap(result->col(2));
- result->col(1).swap(result->col(3));
- return true;
- }
- else
+ typedef typename ResultType::Scalar Scalar;
+ typedef typename MatrixType::RealScalar RealScalar;
+
+ // we will do row permutations on the matrix. This copy should have negligible cost.
+ // if not, consider working in-place on the matrix (const-cast it, but then undo the permutations
+ // to nevertheless honor constness)
+ typename MatrixType::PlainMatrixType matrix(_matrix);
+
+ // let's extract from the 2 first colums a 2x2 block whose determinant is as big as possible.
+ int good_row0=0, good_row1=1;
+ RealScalar good_absdet(-1);
+ // this double for loop shouldn't be too costly: only 6 iterations
+ for(int row0=0; row0<4; ++row0) {
+ for(int row1=row0+1; row1<4; ++row1)
{
- // first, undo the swaps previously made
- m.row(0).swap(m.row(2));
- m.row(1).swap(m.row(3));
- // swap row 0 with the the row among 0 and 1 that has the biggest 2 first coeffs
- int swap0with = ei_abs(m.coeff(0,0))+ei_abs(m.coeff(0,1))>ei_abs(m.coeff(1,0))+ei_abs(m.coeff(1,1)) ? 0 : 1;
- m.row(0).swap(m.row(swap0with));
- // swap row 1 with the the row among 2 and 3 that has the biggest 2 first coeffs
- int swap1with = ei_abs(m.coeff(2,0))+ei_abs(m.coeff(2,1))>ei_abs(m.coeff(3,0))+ei_abs(m.coeff(3,1)) ? 2 : 3;
- m.row(1).swap(m.row(swap1with));
- if( ei_compute_inverse_size4_helper(m, result) )
- {
- result->col(1).swap(result->col(swap1with));
- result->col(0).swap(result->col(swap0with));
- return true;
- }
- else
+ RealScalar absdet = ei_abs(matrix.coeff(row0,0)*matrix.coeff(row1,1)
+ - matrix.coeff(row0,1)*matrix.coeff(row1,0));
+ if(absdet > good_absdet)
{
- // non-invertible matrix
- return false;
+ good_absdet = absdet;
+ good_row0 = row0;
+ good_row1 = row1;
}
}
}
+ // do row permutations to move this 2x2 block to the top
+ matrix.row(0).swap(matrix.row(good_row0));
+ matrix.row(1).swap(matrix.row(good_row1));
+ // now applying our helper function is numerically stable
+ ei_compute_inverse_size4_helper(matrix, result);
+ // Since we did row permutations on the original matrix, we need to do column permutations
+ // in the reverse order on the inverse
+ result.col(1).swap(result.col(good_row1));
+ result.col(0).swap(result.col(good_row0));
}
-
+template<typename MatrixType, typename ResultType>
+void ei_compute_inverse_and_det_size4_with_check(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& result,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
+{
+ determinant = matrix.determinant();
+ invertible = ei_abs(determinant) > absDeterminantThreshold;
+ if(invertible) ei_compute_inverse_size4(matrix, result);
+}
/***********************************************
-*** Part 2 : selector and MatrixBase methods ***
+*** Part 2 : selectors and MatrixBase methods ***
***********************************************/
template<typename MatrixType, typename ResultType, int Size = MatrixType::RowsAtCompileTime>
struct ei_compute_inverse
{
- static inline void run(const MatrixType& matrix, ResultType* result)
+ static inline void run(const MatrixType& matrix, ResultType& result)
{
- *result = matrix.partialLu().inverse();
+ result = matrix.partialLu().inverse();
}
};
template<typename MatrixType, typename ResultType>
struct ei_compute_inverse<MatrixType, ResultType, 1>
{
- static inline void run(const MatrixType& matrix, ResultType* result)
+ static inline void run(const MatrixType& matrix, ResultType& result)
{
typedef typename MatrixType::Scalar Scalar;
- result->coeffRef(0,0) = Scalar(1) / matrix.coeff(0,0);
+ result.coeffRef(0,0) = Scalar(1) / matrix.coeff(0,0);
}
};
template<typename MatrixType, typename ResultType>
struct ei_compute_inverse<MatrixType, ResultType, 2>
{
- static inline void run(const MatrixType& matrix, ResultType* result)
+ static inline void run(const MatrixType& matrix, ResultType& result)
{
ei_compute_inverse_size2(matrix, result);
}
@@ -226,64 +241,53 @@ struct ei_compute_inverse<MatrixType, ResultType, 2>
template<typename MatrixType, typename ResultType>
struct ei_compute_inverse<MatrixType, ResultType, 3>
{
- static inline void run(const MatrixType& matrix, ResultType* result)
+ static inline void run(const MatrixType& matrix, ResultType& result)
{
- ei_compute_inverse_size3<false, MatrixType, ResultType>(matrix, result);
+ ei_compute_inverse_size3(matrix, result);
}
};
template<typename MatrixType, typename ResultType>
struct ei_compute_inverse<MatrixType, ResultType, 4>
{
- static inline void run(const MatrixType& matrix, ResultType* result)
+ static inline void run(const MatrixType& matrix, ResultType& result)
{
- ei_compute_inverse_size4_with_check(matrix, result);
+ ei_compute_inverse_size4(matrix, result);
}
};
/** \lu_module
*
- * Computes the matrix inverse of this matrix.
- *
- * \note This matrix must be invertible, otherwise the result is undefined. If you need an invertibility check, use
- * computeInverseWithCheck().
- *
- * \param result Pointer to the matrix in which to store the result.
- *
- * Example: \include MatrixBase_computeInverse.cpp
- * Output: \verbinclude MatrixBase_computeInverse.out
- *
- * \sa inverse(), computeInverseWithCheck()
- */
-template<typename Derived>
-template<typename ResultType>
-inline void MatrixBase<Derived>::computeInverse(ResultType *result) const
-{
- ei_assert(rows() == cols());
- EIGEN_STATIC_ASSERT(NumTraits<Scalar>::HasFloatingPoint,NUMERIC_TYPE_MUST_BE_FLOATING_POINT)
- ei_compute_inverse<PlainMatrixType, ResultType>::run(eval(), result);
-}
-
-/** \lu_module
- *
* \returns the matrix inverse of this matrix.
*
- * \note This matrix must be invertible, otherwise the result is undefined. If you need an invertibility check, use
- * computeInverseWithCheck().
+ * For small fixed sizes up to 4x4, this method uses ad-hoc methods (cofactors up to 3x3, Euler's trick for 4x4).
+ * In the general case, this method uses class PartialLU.
*
- * \note This method returns a matrix by value, which can be inefficient. To avoid that overhead,
- * use computeInverse() instead.
+ * \note This matrix must be invertible, otherwise the result is undefined. If you need an
+ * invertibility check, do the following:
+ * \li for fixed sizes up to 4x4, use computeInverseAndDetWithCheck().
+ * \li for the general case, use class LU.
*
* Example: \include MatrixBase_inverse.cpp
* Output: \verbinclude MatrixBase_inverse.out
*
- * \sa computeInverse(), computeInverseWithCheck()
+ * \sa computeInverseAndDetWithCheck()
*/
template<typename Derived>
inline const typename MatrixBase<Derived>::PlainMatrixType MatrixBase<Derived>::inverse() const
{
- typename MatrixBase<Derived>::PlainMatrixType result;
- computeInverse(&result);
+ EIGEN_STATIC_ASSERT(NumTraits<Scalar>::HasFloatingPoint,NUMERIC_TYPE_MUST_BE_FLOATING_POINT)
+ ei_assert(rows() == cols());
+ typedef typename MatrixBase<Derived>::PlainMatrixType ResultType;
+ ResultType result(rows(), cols());
+ // for 2x2, it's worth giving a chance to avoid evaluating.
+ // for larger sizes, evaluating has negligible cost and limits code size.
+ typedef typename ei_meta_if<
+ RowsAtCompileTime == 2,
+ typename ei_cleantype<typename ei_nested<Derived,2>::type>::type,
+ PlainMatrixType
+ >::ret MatrixType;
+ ei_compute_inverse<MatrixType, ResultType>::run(derived(), result);
return result;
}
@@ -293,74 +297,108 @@ inline const typename MatrixBase<Derived>::PlainMatrixType MatrixBase<Derived>::
*******************************************/
template<typename MatrixType, typename ResultType, int Size = MatrixType::RowsAtCompileTime>
-struct ei_compute_inverse_with_check
-{
- static inline bool run(const MatrixType& matrix, ResultType* result)
- {
- typedef typename MatrixType::Scalar Scalar;
- LU<MatrixType> lu( matrix );
- if( !lu.isInvertible() ) return false;
- *result = lu.inverse();
- return true;
- }
-};
+struct ei_compute_inverse_and_det_with_check {};
template<typename MatrixType, typename ResultType>
-struct ei_compute_inverse_with_check<MatrixType, ResultType, 1>
+struct ei_compute_inverse_and_det_with_check<MatrixType, ResultType, 1>
{
- static inline bool run(const MatrixType& matrix, ResultType* result)
+ static inline void run(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& result,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
{
- typedef typename MatrixType::Scalar Scalar;
- if( matrix.coeff(0,0) == Scalar(0) ) return false;
- result->coeffRef(0,0) = Scalar(1) / matrix.coeff(0,0);
- return true;
+ determinant = matrix.coeff(0,0);
+ invertible = ei_abs(determinant) > absDeterminantThreshold;
+ if(invertible) result.coeffRef(0,0) = typename ResultType::Scalar(1) / determinant;
}
};
template<typename MatrixType, typename ResultType>
-struct ei_compute_inverse_with_check<MatrixType, ResultType, 2>
+struct ei_compute_inverse_and_det_with_check<MatrixType, ResultType, 2>
{
- static inline bool run(const MatrixType& matrix, ResultType* result)
+ static inline void run(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& result,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
{
- return ei_compute_inverse_size2_with_check(matrix, result);
+ ei_compute_inverse_and_det_size2_with_check
+ (matrix, absDeterminantThreshold, result, determinant, invertible);
}
};
template<typename MatrixType, typename ResultType>
-struct ei_compute_inverse_with_check<MatrixType, ResultType, 3>
+struct ei_compute_inverse_and_det_with_check<MatrixType, ResultType, 3>
{
- static inline bool run(const MatrixType& matrix, ResultType* result)
+ static inline void run(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& result,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
{
- return ei_compute_inverse_size3<true, MatrixType, ResultType>(matrix, result);
+ ei_compute_inverse_and_det_size3_with_check
+ (matrix, absDeterminantThreshold, result, determinant, invertible);
}
};
template<typename MatrixType, typename ResultType>
-struct ei_compute_inverse_with_check<MatrixType, ResultType, 4>
+struct ei_compute_inverse_and_det_with_check<MatrixType, ResultType, 4>
{
- static inline bool run(const MatrixType& matrix, ResultType* result)
+ static inline void run(
+ const MatrixType& matrix,
+ const typename MatrixType::RealScalar& absDeterminantThreshold,
+ ResultType& result,
+ typename ResultType::Scalar& determinant,
+ bool& invertible
+ )
{
- return ei_compute_inverse_size4_with_check(matrix, result);
+ ei_compute_inverse_and_det_size4_with_check
+ (matrix, absDeterminantThreshold, result, determinant, invertible);
}
};
/** \lu_module
*
- * Computation of matrix inverse, with invertibility check.
+ * Computation of matrix inverse and determinant, with invertibility check.
*
- * \returns true if the matrix is invertible, false otherwise.
+ * This is only for fixed-size square matrices of size up to 4x4.
*
- * \param result Pointer to the matrix in which to store the result.
+ * \param inverse Reference to the matrix in which to store the inverse.
+ * \param determinant Reference to the variable in which to store the inverse.
+ * \param invertible Reference to the bool variable in which to store whether the matrix is invertible.
+ * \param absDeterminantThreshold Optional parameter controlling the invertibility check.
+ * The matrix will be declared invertible if the absolute value of its
+ * determinant is greater than this threshold.
*
- * \sa inverse(), computeInverse()
+ * \sa inverse()
*/
template<typename Derived>
template<typename ResultType>
-inline bool MatrixBase<Derived>::computeInverseWithCheck(ResultType *result) const
+inline void MatrixBase<Derived>::computeInverseAndDetWithCheck(
+ ResultType& inverse,
+ typename ResultType::Scalar& determinant,
+ bool& invertible,
+ const RealScalar& absDeterminantThreshold
+ ) const
{
+ // i'd love to put some static assertions there, but SFINAE means that they have no effect...
ei_assert(rows() == cols());
- EIGEN_STATIC_ASSERT(NumTraits<Scalar>::HasFloatingPoint,NUMERIC_TYPE_MUST_BE_FLOATING_POINT)
- return ei_compute_inverse_with_check<PlainMatrixType, ResultType>::run(eval(), result);
+ // for 2x2, it's worth giving a chance to avoid evaluating.
+ // for larger sizes, evaluating has negligible cost and limits code size.
+ typedef typename ei_meta_if<
+ RowsAtCompileTime == 2,
+ typename ei_cleantype<typename ei_nested<Derived, 2>::type>::type,
+ PlainMatrixType
+ >::ret MatrixType;
+ ei_compute_inverse_and_det_with_check<MatrixType, ResultType>::run
+ (derived(), absDeterminantThreshold, inverse, determinant, invertible);
}
diff --git a/test/inverse.cpp b/test/inverse.cpp
index 6fc65786c..b8170a738 100644
--- a/test/inverse.cpp
+++ b/test/inverse.cpp
@@ -53,9 +53,6 @@ template<typename MatrixType> void inverse(const MatrixType& m)
m2 = m1.inverse();
VERIFY_IS_APPROX(m1, m2.inverse() );
- m1.computeInverse(&m2);
- VERIFY_IS_APPROX(m1, m2.inverse() );
-
VERIFY_IS_APPROX((Scalar(2)*m2).inverse(), m2.inverse()*Scalar(0.5));
VERIFY_IS_APPROX(identity, m1.inverse() * m1 );
@@ -66,17 +63,23 @@ template<typename MatrixType> void inverse(const MatrixType& m)
// since for the general case we implement separately row-major and col-major, test that
VERIFY_IS_APPROX(m1.transpose().inverse(), m1.inverse().transpose());
- //computeInverseWithCheck tests
+#if !defined(EIGEN_TEST_PART_5) && !defined(EIGEN_TEST_PART_6)
+ //computeInverseAndDetWithCheck tests
//First: an invertible matrix
- bool invertible = m1.computeInverseWithCheck(&m2);
+ bool invertible;
+ RealScalar det;
+ m1.computeInverseAndDetWithCheck(m2, det, invertible);
VERIFY(invertible);
VERIFY_IS_APPROX(identity, m1*m2);
+ VERIFY_IS_APPROX(det, m1.determinant());
//Second: a rank one matrix (not invertible, except for 1x1 matrices)
VectorType v3 = VectorType::Random(rows);
MatrixType m3 = v3*v3.transpose(), m4(rows,cols);
- invertible = m3.computeInverseWithCheck( &m4 );
+ m3.computeInverseAndDetWithCheck(m4, det, invertible);
VERIFY( rows==1 ? invertible : !invertible );
+ VERIFY_IS_APPROX(det, m3.determinant());
+#endif
}
void test_inverse()