Add support for automatic-size deduction in reshaped, e.g.:

mat.reshaped(4,AutoSize); <-> mat.reshaped(4,mat.size()/4);

Eigen/Core

@@ -431,6 +431,7 @@ using std::ptrdiff_t;
 #include "src/Core/arch/CUDA/Complex.h"
 
 #include "src/Core/util/IndexedViewHelper.h"
+#include "src/Core/util/ReshapedHelper.h"
 #include "src/Core/ArithmeticSequence.h"
 #include "src/Core/DenseCoeffsBase.h"
 #include "src/Core/DenseBase.h"

Eigen/src/Core/util/ReshapedHelper.h

@@ -0,0 +1,45 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2017 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+#ifndef EIGEN_RESHAPED_HELPER_H
+#define EIGEN_RESHAPED_HELPER_H
+
+namespace Eigen {
+
+enum AutoSize_t   { AutoSize };
+
+namespace internal {
+
+template<typename SizeType,typename OtherSize, int TotalSize>
+struct get_compiletime_reshape_size {
+  enum { value = get_fixed_value<SizeType>::value };
+};
+
+template<typename SizeType>
+Index get_runtime_reshape_size(SizeType size, Index /*other*/, Index /*total*/) {
+  return internal::get_runtime_value(size);
+}
+
+template<typename OtherSize, int TotalSize>
+struct get_compiletime_reshape_size<AutoSize_t,OtherSize,TotalSize> {
+  enum {
+    other_size = get_fixed_value<OtherSize>::value,
+    value = (TotalSize==Dynamic || other_size==Dynamic) ? Dynamic : TotalSize / other_size };
+};
+
+Index get_runtime_reshape_size(AutoSize_t /*size*/, Index other, Index total) {
+  return total/other;
+}
+
+}
+
+} // end namespace Eigen
+
+#endif // EIGEN_RESHAPED_HELPER_H

Eigen/src/plugins/ReshapedMethods.h

@@ -28,62 +28,70 @@ template<typename NRowsType, typename NColsType, typename OrderType>
 EIGEN_DEVICE_FUNC
 inline const Reshaped<const Derived,...>
 reshaped(NRowsType nRows, NColsType nCols, OrderType = ColOrder) const;
+
 #else
+
+// This file is automatically included twice to generate const and non-const versions
+
+#ifndef EIGEN_RESHAPED_METHOD_2ND_PASS
+#define EIGEN_RESHAPED_METHOD_CONST const
+#else
+#define EIGEN_RESHAPED_METHOD_CONST
+#endif
+
+#ifndef EIGEN_RESHAPED_METHOD_2ND_PASS
+
+// This part is included once
+
+#endif
+
 template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-inline Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>
+inline Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,
-reshaped(NRowsType nRows, NColsType nCols)
+                internal::get_compiletime_reshape_size<NRowsType,NColsType,SizeAtCompileTime>::value,
+                internal::get_compiletime_reshape_size<NColsType,NRowsType,SizeAtCompileTime>::value>
+reshaped(NRowsType nRows, NColsType nCols) EIGEN_RESHAPED_METHOD_CONST
 {
-  return Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>(
+  return Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
+                  internal::get_compiletime_reshape_size<NRowsType,NColsType,SizeAtCompileTime>::value,
+                  internal::get_compiletime_reshape_size<NColsType,NRowsType,SizeAtCompileTime>::value>
+                (derived(),
+                 internal::get_runtime_reshape_size(nRows,internal::get_runtime_value(nCols),size()),
+                 internal::get_runtime_reshape_size(nCols,internal::get_runtime_value(nRows),size()));
 }
 
 template<typename NRowsType, typename NColsType, typename OrderType>
 EIGEN_DEVICE_FUNC
-inline Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
+inline Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,
+                internal::get_compiletime_reshape_size<NRowsType,NColsType,SizeAtCompileTime>::value,
+                internal::get_compiletime_reshape_size<NColsType,NRowsType,SizeAtCompileTime>::value,
                 OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>
-reshaped(NRowsType nRows, NColsType nCols, OrderType)
+reshaped(NRowsType nRows, NColsType nCols, OrderType) EIGEN_RESHAPED_METHOD_CONST
 {
-  return Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
+  return Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,
-                  OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>(
+                  internal::get_compiletime_reshape_size<NRowsType,NColsType,SizeAtCompileTime>::value,
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
+                  internal::get_compiletime_reshape_size<NColsType,NRowsType,SizeAtCompileTime>::value,
-}
-
-
-template<typename NRowsType, typename NColsType>
-EIGEN_DEVICE_FUNC
-inline const Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>
-reshaped(NRowsType nRows, NColsType nCols) const
-{
-  return Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>(
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
-}
-
-template<typename NRowsType, typename NColsType, typename OrderType>
-EIGEN_DEVICE_FUNC
-inline const Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
                   OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>
-reshaped(NRowsType nRows, NColsType nCols, OrderType) const
+                (derived(),
-{
+                 internal::get_runtime_reshape_size(nRows,internal::get_runtime_value(nCols),size()),
-  return Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
+                 internal::get_runtime_reshape_size(nCols,internal::get_runtime_value(nRows),size()));
-                  OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>(
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
 }
 
 // Views as linear vectors
 
 EIGEN_DEVICE_FUNC
-inline const Reshaped<Derived,SizeAtCompileTime,1>
+inline Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,SizeAtCompileTime,1>
-operator()(const Eigen::internal::all_t&)
+operator()(const Eigen::internal::all_t&) EIGEN_RESHAPED_METHOD_CONST
 {
-  return Reshaped<Derived,SizeAtCompileTime,1>(derived(),size(),1);
+  return Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,SizeAtCompileTime,1>(derived(),size(),1);
 }
 
-EIGEN_DEVICE_FUNC
+#undef EIGEN_RESHAPED_METHOD_CONST
-inline const Reshaped<const Derived,SizeAtCompileTime,1>
+
-operator()(const Eigen::internal::all_t&) const
+#ifndef EIGEN_RESHAPED_METHOD_2ND_PASS
-{
+#define EIGEN_RESHAPED_METHOD_2ND_PASS
-  return Reshaped<const Derived,SizeAtCompileTime,1>(derived(),size(),1);
+#include "ReshapedMethods.h"
-}
+#undef EIGEN_RESHAPED_METHOD_2ND_PASS
+#endif
 
 #endif // EIGEN_PARSED_BY_DOXYGEN

test/reshape.cpp

@@ -17,10 +17,48 @@ is_same_eq(const T1& a, const T2& b)
   return (a.array() == b.array()).all();
 }
 
+template <typename MatType,typename OrderType>
+void check_auto_reshape4x4(MatType m,OrderType order)
+{
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 1>  v1( 1);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 2>  v2( 2);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 4>  v4( 4);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 8>  v8( 8);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1:16> v16(16);
+
+  VERIFY(is_same_eq(m.reshaped( 1,       AutoSize, order), m.reshaped( 1, 16, order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 16,       order), m.reshaped( 1, 16, order)));
+  VERIFY(is_same_eq(m.reshaped( 2,       AutoSize, order), m.reshaped( 2,  8, order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 8,        order), m.reshaped( 2,  8, order)));
+  VERIFY(is_same_eq(m.reshaped( 4,       AutoSize, order), m.reshaped( 4,  4, order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 4,        order), m.reshaped( 4,  4, order)));
+  VERIFY(is_same_eq(m.reshaped( 8,       AutoSize, order), m.reshaped( 8,  2, order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 2,        order), m.reshaped( 8,  2, order)));
+  VERIFY(is_same_eq(m.reshaped(16,       AutoSize, order), m.reshaped(16,  1, order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 1,       order),  m.reshaped(16,  1, order)));
+
+  VERIFY(is_same_eq(m.reshaped(fix< 1>,   AutoSize, order),  m.reshaped(fix< 1>, v16,     order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix<16>,  order),  m.reshaped( v1,     fix<16>, order)));
+  VERIFY(is_same_eq(m.reshaped(fix< 2>,   AutoSize, order),  m.reshaped(fix< 2>, v8,      order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 8>,  order),  m.reshaped( v2,     fix< 8>, order)));
+  VERIFY(is_same_eq(m.reshaped(fix< 4>,   AutoSize, order),  m.reshaped(fix< 4>, v4,      order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 4>,  order),  m.reshaped( v4,     fix< 4>, order)));
+  VERIFY(is_same_eq(m.reshaped(fix< 8>,   AutoSize, order),  m.reshaped(fix< 8>, v2,      order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 2>,  order),  m.reshaped( v8,     fix< 2>, order)));
+  VERIFY(is_same_eq(m.reshaped(fix<16>,   AutoSize, order),  m.reshaped(fix<16>, v1,      order)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 1>,  order),  m.reshaped(v16,     fix< 1>, order)));
+}
+
 // just test a 4x4 matrix, enumerate all combination manually
 template <typename MatType>
 void reshape4x4(MatType m)
 {
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 1>  v1( 1);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 2>  v2( 2);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 4>  v4( 4);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1: 8>  v8( 8);
+  internal::VariableAndFixedInt<MatType::SizeAtCompileTime==Dynamic?-1:16> v16(16);
+
   if((MatType::Flags&RowMajorBit)==0)
   {
     typedef Map<MatrixXi> MapMat;
@@ -38,6 +76,7 @@ void reshape4x4(MatType m)
     VERIFY_IS_EQUAL(m.reshaped(fix< 8>, fix< 2>), MapMat(m.data(),  8,  2));
     VERIFY_IS_EQUAL(m.reshaped(fix<16>, fix< 1>), MapMat(m.data(), 16,  1));
 
+
     // reshape chain
     VERIFY_IS_EQUAL(
       (m
@@ -56,6 +95,35 @@ void reshape4x4(MatType m)
     );
   }
 
+  VERIFY(is_same_eq(m.reshaped( 1,       AutoSize), m.reshaped( 1, 16)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 16),       m.reshaped( 1, 16)));
+  VERIFY(is_same_eq(m.reshaped( 2,       AutoSize), m.reshaped( 2,  8)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 8),        m.reshaped( 2,  8)));
+  VERIFY(is_same_eq(m.reshaped( 4,       AutoSize), m.reshaped( 4,  4)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 4),        m.reshaped( 4,  4)));
+  VERIFY(is_same_eq(m.reshaped( 8,       AutoSize), m.reshaped( 8,  2)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize, 2),        m.reshaped( 8,  2)));
+  VERIFY(is_same_eq(m.reshaped(16,       AutoSize), m.reshaped(16,  1)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  1),       m.reshaped(16,  1)));
+
+  VERIFY(is_same_eq(m.reshaped(fix< 1>,   AutoSize),  m.reshaped(fix< 1>, v16)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix<16>),   m.reshaped( v1,     fix<16>)));
+  VERIFY(is_same_eq(m.reshaped(fix< 2>,   AutoSize),  m.reshaped(fix< 2>, v8)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 8>),   m.reshaped( v2,     fix< 8>)));
+  VERIFY(is_same_eq(m.reshaped(fix< 4>,   AutoSize),  m.reshaped(fix< 4>, v4)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 4>),   m.reshaped( v4,     fix< 4>)));
+  VERIFY(is_same_eq(m.reshaped(fix< 8>,   AutoSize),  m.reshaped(fix< 8>, v2)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 2>),   m.reshaped( v8,     fix< 2>)));
+  VERIFY(is_same_eq(m.reshaped(fix<16>,   AutoSize),  m.reshaped(fix<16>, v1)));
+  VERIFY(is_same_eq(m.reshaped(AutoSize,  fix< 1>),   m.reshaped(v16,     fix< 1>)));
+
+  check_auto_reshape4x4(m,ColOrder);
+  check_auto_reshape4x4(m,RowOrder);
+  check_auto_reshape4x4(m,AutoOrder);
+  check_auto_reshape4x4(m.transpose(),ColOrder);
+  check_auto_reshape4x4(m.transpose(),RowOrder);
+  check_auto_reshape4x4(m.transpose(),AutoOrder);
+
   VERIFY_IS_EQUAL(m.reshaped( 1, 16).data(), m.data());
   VERIFY_IS_EQUAL(m.reshaped( 1, 16).innerStride(), 1);
 
@@ -82,12 +150,15 @@ void reshape4x4(MatType m)
   VERIFY_IS_EQUAL( m28r1, m28r2);
 
   using placeholders::all;
-  VERIFY(is_same_eq(m.reshaped(fix<MatType::SizeAtCompileTime>(m.size()),fix<1>), m(all)));
+  VERIFY(is_same_eq(m.reshaped(v16,fix<1>), m(all)));
   VERIFY_IS_EQUAL(m.reshaped(16,1), m(all));
   VERIFY_IS_EQUAL(m.reshaped(1,16), m(all).transpose());
   VERIFY_IS_EQUAL(m(all).reshaped(2,8), m.reshaped(2,8));
   VERIFY_IS_EQUAL(m(all).reshaped(4,4), m.reshaped(4,4));
   VERIFY_IS_EQUAL(m(all).reshaped(8,2), m.reshaped(8,2));
+
+  VERIFY(is_same_eq(m.reshaped(AutoSize,fix<1>), m(all)));
+  VERIFY_IS_EQUAL(m.reshaped(fix<1>,AutoSize,RowOrder), m.transpose()(all).transpose());
 }
 
 void test_reshape()