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

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

3 files changed, 91 insertions, 37 deletions

diff --git a/Eigen/Core b/Eigen/Core
index 1174d7d16..1af688637 100644
--- a/Eigen/Core
+++ b/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"
diff --git a/Eigen/src/Core/util/ReshapedHelper.h b/Eigen/src/Core/util/ReshapedHelper.h
new file mode 100644
index 000000000..b5d59cfe8
--- /dev/null
+++ b/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
diff --git a/Eigen/src/plugins/ReshapedMethods.h b/Eigen/src/plugins/ReshapedMethods.h
index fc7cdcfa7..118841798 100644
--- a/Eigen/src/plugins/ReshapedMethods.h
+++ b/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
-template<typename NRowsType, typename NColsType>
-EIGEN_DEVICE_FUNC
-inline Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>
-reshaped(NRowsType nRows, NColsType nCols)
-{
-  return Reshaped<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 Reshaped<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)
-{
-  return Reshaped<Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
-                  OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>(
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
-}
+// 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 const Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>
-reshaped(NRowsType nRows, NColsType nCols) const
+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>
+reshaped(NRowsType nRows, NColsType nCols) EIGEN_RESHAPED_METHOD_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));
+  return Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,
+                  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 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
+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) EIGEN_RESHAPED_METHOD_CONST
 {
-  return Reshaped<const Derived,internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value,
-                  OrderType::value==AutoOrderValue?Flags&RowMajorBit:OrderType::value>(
-            derived(), internal::get_runtime_value(nRows), internal::get_runtime_value(nCols));
+  return 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>
+                (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()));
 }
 
 // Views as linear vectors
 
 EIGEN_DEVICE_FUNC
-inline const Reshaped<Derived,SizeAtCompileTime,1>
-operator()(const Eigen::internal::all_t&)
+inline Reshaped<EIGEN_RESHAPED_METHOD_CONST Derived,SizeAtCompileTime,1>
+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
-inline const Reshaped<const Derived,SizeAtCompileTime,1>
-operator()(const Eigen::internal::all_t&) const
-{
-  return Reshaped<const Derived,SizeAtCompileTime,1>(derived(),size(),1);
-}
+#undef EIGEN_RESHAPED_METHOD_CONST
+
+#ifndef EIGEN_RESHAPED_METHOD_2ND_PASS
+#define EIGEN_RESHAPED_METHOD_2ND_PASS
+#include "ReshapedMethods.h"
+#undef EIGEN_RESHAPED_METHOD_2ND_PASS
+#endif
 
 #endif // EIGEN_PARSED_BY_DOXYGEN