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Factories code between numext::hypot and scalar_hyot_op functor.

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This commit is contained in:
Gael Guennebaud 2018-04-04 15:12:43 +02:00
parent 368dd4cd9d
commit 4213b63f5c
2 changed files with 21 additions and 24 deletions
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20
Eigen/src/Core/MathFunctionsImpl.h
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@ -66,6 +66,17 @@ T generic_fast_tanh_float(const T& a_x)
return pdiv(p, q);
}
template<typename RealScalar>
EIGEN_STRONG_INLINE
RealScalar positive_real_hypot(const RealScalar& x, const RealScalar& y)
{
EIGEN_USING_STD_MATH(sqrt);
RealScalar p, qp;
p = numext::maxi(x,y);
if(p==RealScalar(0)) return RealScalar(0);
qp = numext::mini(y,x) / p;
return p * sqrt(RealScalar(1) + qp*qp);
}
template<typename Scalar>
struct hypot_impl
@ -74,14 +85,7 @@ struct hypot_impl
static inline RealScalar run(const Scalar& x, const Scalar& y)
{
EIGEN_USING_STD_MATH(abs);
EIGEN_USING_STD_MATH(sqrt);
RealScalar _x = abs(x);
RealScalar _y = abs(y);
RealScalar p, qp;
p = numext::maxi(_x,_y);
if(p==RealScalar(0)) return RealScalar(0);
qp = numext::mini(_y,_x) / p;
return p * sqrt(RealScalar(1) + qp*qp);
return positive_real_hypot(abs(x), abs(y));
}
};

25
Eigen/src/Core/functors/BinaryFunctors.h
View File

@ -255,7 +255,7 @@ struct scalar_cmp_op<LhsScalar,RhsScalar, cmp_NEQ> : binary_op_base<LhsScalar,Rh
/** \internal
* \brief Template functor to compute the hypot of two scalars
* \brief Template functor to compute the hypot of two \b positive \b and \b real scalars
*
* \sa MatrixBase::stableNorm(), class Redux
*/
@ -263,22 +263,15 @@ template<typename Scalar>
struct scalar_hypot_op<Scalar,Scalar> : binary_op_base<Scalar,Scalar>
{
EIGEN_EMPTY_STRUCT_CTOR(scalar_hypot_op)
// typedef typename NumTraits<Scalar>::Real result_type;
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& _x, const Scalar& _y) const
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar &x, const Scalar &y) const
{
EIGEN_USING_STD_MATH(sqrt)
Scalar p, qp;
if(_x>_y)
{
p = _x;
qp = _y / p;
}
else
{
p = _y;
qp = _x / p;
}
return p * sqrt(Scalar(1) + qp*qp);
// This functor is used by hypotNorm only for which it is faster to first apply abs
// on all coefficients prior to reduction through hypot.
// This way we avoid calling abs on positive and real entries, and this also permits
// to seamlessly handle complexes. Otherwise we would have to handle both real and complexes
// through the same functor...
return internal::positive_real_hypot(x,y);
}
};
template<typename Scalar>