Bug #1785: Introduce numext::rint.

This provides a new op that matches std::rint and previous behavior of
pround. Also adds corresponding unsupported/../Tensor op.
Performance is the same as e. g. floor (tested SSE/AVX).

Eigen/src/Core/GenericPacketMath.h

@@ -92,6 +92,7 @@ struct default_packet_traits
     HasBetaInc = 0,
 
     HasRound  = 0,
+    HasRint   = 0,
     HasFloor  = 0,
     HasCeil   = 0,
 
@@ -575,6 +576,11 @@ Packet pround(const Packet& a) { using numext::round; return round(a); }
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pfloor(const Packet& a) { using numext::floor; return floor(a); }
 
+/** \internal \returns the rounded value of \a a (coeff-wise) with current
+ * rounding mode */
+template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
+Packet print(const Packet& a) { using numext::rint; return rint(a); }
+
 /** \internal \returns the ceil of \a a (coeff-wise) */
 template<typename Packet> EIGEN_DECLARE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet pceil(const Packet& a) { using numext::ceil; return ceil(a); }

Eigen/src/Core/GlobalFunctions.h

@@ -89,6 +89,7 @@ namespace Eigen
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(rsqrt,scalar_rsqrt_op,reciprocal square root,\sa ArrayBase::rsqrt)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(square,scalar_square_op,square (power 2),\sa Eigen::abs2 DOXCOMMA Eigen::pow DOXCOMMA ArrayBase::square)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(cube,scalar_cube_op,cube (power 3),\sa Eigen::pow DOXCOMMA ArrayBase::cube)
+  EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(rint,scalar_rint_op,nearest integer,\sa Eigen::floor DOXCOMMA Eigen::ceil DOXCOMMA ArrayBase::round)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(round,scalar_round_op,nearest integer,\sa Eigen::floor DOXCOMMA Eigen::ceil DOXCOMMA ArrayBase::round)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(floor,scalar_floor_op,nearest integer not greater than the giben value,\sa Eigen::ceil DOXCOMMA ArrayBase::floor)
   EIGEN_ARRAY_DECLARE_GLOBAL_UNARY(ceil,scalar_ceil_op,nearest integer not less than the giben value,\sa Eigen::floor DOXCOMMA ArrayBase::ceil)

Eigen/src/Core/MathFunctions.h

@@ -429,6 +429,38 @@ struct round_retval
   typedef Scalar type;
 };
 
+/****************************************************************************
+* Implementation of rint                                                    *
+****************************************************************************/
+
+template<typename Scalar>
+struct rint_impl {
+  static inline Scalar run(const Scalar& x)
+  {
+    EIGEN_STATIC_ASSERT((!NumTraits<Scalar>::IsComplex), NUMERIC_TYPE_MUST_BE_REAL)
+#if EIGEN_HAS_CXX11_MATH
+      EIGEN_USING_STD_MATH(rint);
+#endif
+    return rint(x);
+  }
+};
+
+#if !EIGEN_HAS_CXX11_MATH
+template<>
+struct rint_impl<float> {
+  static inline float run(const float& x)
+  {
+    return rintf(x);
+  }
+};
+#endif
+
+template<typename Scalar>
+struct rint_retval
+{
+  typedef Scalar type;
+};
+
 /****************************************************************************
 * Implementation of arg                                                     *
 ****************************************************************************/
@@ -1194,6 +1226,13 @@ SYCL_SPECIALIZE_FLOATING_TYPES_UNARY_FUNC_RET_TYPE(isinf, isinf, bool)
 SYCL_SPECIALIZE_FLOATING_TYPES_UNARY_FUNC_RET_TYPE(isfinite, isfinite, bool)
 #endif
 
+template<typename Scalar>
+EIGEN_DEVICE_FUNC
+inline EIGEN_MATHFUNC_RETVAL(rint, Scalar) rint(const Scalar& x)
+{
+  return EIGEN_MATHFUNC_IMPL(rint, Scalar)::run(x);
+}
+
 template<typename Scalar>
 EIGEN_DEVICE_FUNC
 inline EIGEN_MATHFUNC_RETVAL(round, Scalar) round(const Scalar& x)

Eigen/src/Core/arch/AVX/PacketMath.h

@@ -81,7 +81,8 @@ template<> struct packet_traits<float>  : default_packet_traits
     HasBlend = 1,
     HasRound = 1,
     HasFloor = 1,
-    HasCeil = 1
+    HasCeil = 1,
+    HasRint = 1
   };
 };
 template<> struct packet_traits<double> : default_packet_traits
@@ -316,6 +317,8 @@ template<> EIGEN_STRONG_INLINE Packet8i pcmp_eq(const Packet8i& a, const Packet8
 #endif
 }
 
+template<> EIGEN_STRONG_INLINE Packet8f print<Packet8f>(const Packet8f& a) { return _mm256_round_ps(a, _MM_FROUND_CUR_DIRECTION); }
+template<> EIGEN_STRONG_INLINE Packet4d print<Packet4d>(const Packet4d& a) { return _mm256_round_pd(a, _MM_FROUND_CUR_DIRECTION); }
 
 template<> EIGEN_STRONG_INLINE Packet8f pceil<Packet8f>(const Packet8f& a) { return _mm256_ceil_ps(a); }
 template<> EIGEN_STRONG_INLINE Packet4d pceil<Packet4d>(const Packet4d& a) { return _mm256_ceil_pd(a); }

Eigen/src/Core/arch/SSE/PacketMath.h

@@ -124,6 +124,7 @@ struct packet_traits<float> : default_packet_traits {
 
 #ifdef EIGEN_VECTORIZE_SSE4_1
     ,
+    HasRint = 1,
     HasRound = 1,
     HasCeil = 1
 #endif
@@ -148,6 +149,7 @@ struct packet_traits<double> : default_packet_traits {
 #ifdef EIGEN_VECTORIZE_SSE4_1
     ,
     HasRound = 1,
+    HasRint = 1,
     HasFloor = 1,
     HasCeil = 1
 #endif
@@ -443,6 +445,9 @@ template<> EIGEN_STRONG_INLINE Packet2d pround<Packet2d>(const Packet2d& a)
   return _mm_round_pd(padd(por(pand(a, mask), prev0dot5), a), _MM_FROUND_TO_ZERO);
 }
 
+template<> EIGEN_STRONG_INLINE Packet4f print<Packet4f>(const Packet4f& a) { return _mm_round_ps(a, _MM_FROUND_CUR_DIRECTION); }
+template<> EIGEN_STRONG_INLINE Packet2d print<Packet2d>(const Packet2d& a) { return _mm_round_pd(a, _MM_FROUND_CUR_DIRECTION); }
+
 template<> EIGEN_STRONG_INLINE Packet4f pceil<Packet4f>(const Packet4f& a) { return _mm_ceil_ps(a); }
 template<> EIGEN_STRONG_INLINE Packet2d pceil<Packet2d>(const Packet2d& a) { return _mm_ceil_pd(a); }
 

Eigen/src/Core/functors/UnaryFunctors.h

@@ -735,6 +735,25 @@ struct functor_traits<scalar_floor_op<Scalar> >
   };
 };
 
+/** \internal
+  * \brief Template functor to compute the rounded (with current rounding mode)  value of a scalar
+  * \sa class CwiseUnaryOp, ArrayBase::rint()
+  */
+template<typename Scalar> struct scalar_rint_op {
+  EIGEN_EMPTY_STRUCT_CTOR(scalar_rint_op)
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { return numext::rint(a); }
+  template <typename Packet>
+  EIGEN_DEVICE_FUNC inline Packet packetOp(const Packet& a) const { return internal::print(a); }
+};
+template<typename Scalar>
+struct functor_traits<scalar_rint_op<Scalar> >
+{
+  enum {
+    Cost = NumTraits<Scalar>::MulCost,
+    PacketAccess = packet_traits<Scalar>::HasRint
+  };
+};
+
 /** \internal
   * \brief Template functor to compute the ceil of a scalar
   * \sa class CwiseUnaryOp, ArrayBase::ceil()

Eigen/src/plugins/ArrayCwiseUnaryOps.h

@@ -32,6 +32,7 @@ typedef CwiseUnaryOp<internal::scalar_cosh_op<Scalar>, const Derived> CoshReturn
 typedef CwiseUnaryOp<internal::scalar_square_op<Scalar>, const Derived> SquareReturnType;
 typedef CwiseUnaryOp<internal::scalar_cube_op<Scalar>, const Derived> CubeReturnType;
 typedef CwiseUnaryOp<internal::scalar_round_op<Scalar>, const Derived> RoundReturnType;
+typedef CwiseUnaryOp<internal::scalar_rint_op<Scalar>, const Derived> RintReturnType;
 typedef CwiseUnaryOp<internal::scalar_floor_op<Scalar>, const Derived> FloorReturnType;
 typedef CwiseUnaryOp<internal::scalar_ceil_op<Scalar>, const Derived> CeilReturnType;
 typedef CwiseUnaryOp<internal::scalar_isnan_op<Scalar>, const Derived> IsNaNReturnType;
@@ -427,6 +428,20 @@ cube() const
   return CubeReturnType(derived());
 }
 
+/** \returns an expression of the coefficient-wise rint of *this.
+  *
+  * Example: \include Cwise_rint.cpp
+  * Output: \verbinclude Cwise_rint.out
+  *
+  * \sa <a href="group__CoeffwiseMathFunctions.html#cwisetable_rint">Math functions</a>, ceil(), floor()
+  */
+EIGEN_DEVICE_FUNC
+inline const RintReturnType
+rint() const
+{
+  return RintReturnType(derived());
+}
+
 /** \returns an expression of the coefficient-wise round of *this.
   *
   * Example: \include Cwise_round.cpp