diff options
| -rw-r--r-- | Eigen/src/Core/Dot.h | 19 | ||||
| -rw-r--r-- | test/adjoint.cpp | 9 |
2 files changed, 25 insertions, 3 deletions
diff --git a/Eigen/src/Core/Dot.h b/Eigen/src/Core/Dot.h index ce42854cd..221fc3224 100644 --- a/Eigen/src/Core/Dot.h +++ b/Eigen/src/Core/Dot.h @@ -102,7 +102,10 @@ inline typename NumTraits<typename internal::traits<Derived>::Scalar>::Real Matr return numext::sqrt(squaredNorm()); } -/** \returns an expression of the quotient of *this by its own norm. +/** \returns an expression of the quotient of \c *this by its own norm. + * + * \warning If the input vector is too small (i.e., this->norm()==0), + * then this function returns a copy of the input. * * \only_for_vectors * @@ -114,19 +117,29 @@ MatrixBase<Derived>::normalized() const { typedef typename internal::nested_eval<Derived,2>::type _Nested; _Nested n(derived()); - return n / n.norm(); + RealScalar z = n.squaredNorm(); + // NOTE: after extensive benchmarking, this conditional does not impact performance, at least on recent x86 CPU + if(z>RealScalar(0)) + return n / numext::sqrt(z); + else + return n; } /** Normalizes the vector, i.e. divides it by its own norm. * * \only_for_vectors * + * \warning If the input vector is too small (i.e., this->norm()==0), then \c *this is left unchanged. + * * \sa norm(), normalized() */ template<typename Derived> inline void MatrixBase<Derived>::normalize() { - *this /= norm(); + RealScalar z = squaredNorm(); + // NOTE: after extensive benchmarking, this conditional does not impact performance, at least on recent x86 CPU + if(z>RealScalar(0)) + derived() /= numext::sqrt(z); } //---------- implementation of other norms ---------- diff --git a/test/adjoint.cpp b/test/adjoint.cpp index 3b2a53c91..b1e69c2e5 100644 --- a/test/adjoint.cpp +++ b/test/adjoint.cpp @@ -42,6 +42,15 @@ template<> struct adjoint_specific<false> { VERIFY_IS_APPROX(v1, v1.norm() * v3); VERIFY_IS_APPROX(v3, v1.normalized()); VERIFY_IS_APPROX(v3.norm(), RealScalar(1)); + + // check null inputs + VERIFY_IS_APPROX((v1*0).normalized(), (v1*0)); + RealScalar very_small = (std::numeric_limits<RealScalar>::min)(); + VERIFY( (v1*very_small).norm() == 0 ); + VERIFY_IS_APPROX((v1*very_small).normalized(), (v1*very_small)); + v3 = v1*very_small; + v3.normalize(); + VERIFY_IS_APPROX(v3, (v1*very_small)); // check compatibility of dot and adjoint ref = NumTraits<Scalar>::IsInteger ? 0 : (std::max)((std::max)(v1.norm(),v2.norm()),(std::max)((square * v2).norm(),(square.adjoint() * v1).norm())); |