From d0980c7706c2ed3e60cd47b3fa38c6912245706d Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 26 Oct 2015 16:16:24 +0100
Subject: [PATCH] bug #1092: fix iterative solver ctors for expressions as
 input

---
 Eigen/src/IterativeLinearSolvers/BiCGSTAB.h      |  3 ++-
 .../IterativeLinearSolvers/ConjugateGradient.h   |  3 ++-
 test/sparse_solver.h                             | 16 ++++++++++++++++
 unsupported/Eigen/src/IterativeSolvers/DGMRES.h  |  4 ++--
 unsupported/Eigen/src/IterativeSolvers/GMRES.h   |  3 ++-
 unsupported/Eigen/src/IterativeSolvers/MINRES.h  |  3 ++-
 6 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h b/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h
index 2625c4dc3..551221907 100644
--- a/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h
+++ b/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h
@@ -186,7 +186,8 @@ public:
     * this class becomes invalid. Call compute() to update it with the new
     * matrix A, or modify a copy of A.
     */
-  BiCGSTAB(const MatrixType& A) : Base(A) {}
+  template<typename MatrixDerived>
+  explicit BiCGSTAB(const EigenBase<MatrixDerived>& A) : Base(A.derived()) {}
 
   ~BiCGSTAB() {}
   
diff --git a/Eigen/src/IterativeLinearSolvers/ConjugateGradient.h b/Eigen/src/IterativeLinearSolvers/ConjugateGradient.h
index 8ba4a8dbe..1a7e569c8 100644
--- a/Eigen/src/IterativeLinearSolvers/ConjugateGradient.h
+++ b/Eigen/src/IterativeLinearSolvers/ConjugateGradient.h
@@ -176,7 +176,8 @@ public:
     * this class becomes invalid. Call compute() to update it with the new
     * matrix A, or modify a copy of A.
     */
-  ConjugateGradient(const MatrixType& A) : Base(A) {}
+  template<typename MatrixDerived>
+  explicit ConjugateGradient(const EigenBase<MatrixDerived>& A) : Base(A.derived()) {}
 
   ~ConjugateGradient() {}
   
diff --git a/test/sparse_solver.h b/test/sparse_solver.h
index 833c0d889..e1619d62a 100644
--- a/test/sparse_solver.h
+++ b/test/sparse_solver.h
@@ -67,6 +67,22 @@ void check_sparse_solving(Solver& solver, const typename Solver::MatrixType& A,
     VERIFY(oldb.isApprox(db) && "sparse solver testing: the rhs should not be modified!");
     VERIFY(x.isApprox(refX,test_precision<Scalar>()));
   }
+
+  // if not too large, do some extra check:
+  if(A.rows()<2000)
+  {
+
+    // test expression as input
+    {
+      solver.compute(0.5*(A+A));
+      Rhs x = solver.solve(b);
+      VERIFY(x.isApprox(refX,test_precision<Scalar>()));
+
+      Solver solver2(0.5*(A+A));
+      Rhs x2 = solver2.solve(b);
+      VERIFY(x2.isApprox(refX,test_precision<Scalar>()));
+    }
+  }
 }
 
 template<typename Solver, typename Rhs>
diff --git a/unsupported/Eigen/src/IterativeSolvers/DGMRES.h b/unsupported/Eigen/src/IterativeSolvers/DGMRES.h
index 9fcc8a8d9..68fc997f7 100644
--- a/unsupported/Eigen/src/IterativeSolvers/DGMRES.h
+++ b/unsupported/Eigen/src/IterativeSolvers/DGMRES.h
@@ -133,8 +133,8 @@ class DGMRES : public IterativeSolverBase<DGMRES<_MatrixType,_Preconditioner> >
     * this class becomes invalid. Call compute() to update it with the new
     * matrix A, or modify a copy of A.
     */
-  DGMRES(const MatrixType& A) : Base(A),m_restart(30),m_neig(0),m_r(0),m_maxNeig(5),m_isDeflAllocated(false),m_isDeflInitialized(false)
-  {}
+  template<typename MatrixDerived>
+  explicit DGMRES(const EigenBase<MatrixDerived>& A) : Base(A.derived()), m_restart(30),m_neig(0),m_r(0),m_maxNeig(5),m_isDeflAllocated(false),m_isDeflInitialized(false) {}
 
   ~DGMRES() {}
   
diff --git a/unsupported/Eigen/src/IterativeSolvers/GMRES.h b/unsupported/Eigen/src/IterativeSolvers/GMRES.h
index 7ba13afd2..ea5deb26d 100644
--- a/unsupported/Eigen/src/IterativeSolvers/GMRES.h
+++ b/unsupported/Eigen/src/IterativeSolvers/GMRES.h
@@ -285,7 +285,8 @@ public:
     * this class becomes invalid. Call compute() to update it with the new
     * matrix A, or modify a copy of A.
     */
-  GMRES(const MatrixType& A) : Base(A), m_restart(30) {}
+  template<typename MatrixDerived>
+  explicit GMRES(const EigenBase<MatrixDerived>& A) : Base(A.derived()), m_restart(30) {}
 
   ~GMRES() {}
   
diff --git a/unsupported/Eigen/src/IterativeSolvers/MINRES.h b/unsupported/Eigen/src/IterativeSolvers/MINRES.h
index 30f26aa50..670f274bb 100644
--- a/unsupported/Eigen/src/IterativeSolvers/MINRES.h
+++ b/unsupported/Eigen/src/IterativeSolvers/MINRES.h
@@ -228,7 +228,8 @@ namespace Eigen {
          * this class becomes invalid. Call compute() to update it with the new
          * matrix A, or modify a copy of A.
          */
-        MINRES(const MatrixType& A) : Base(A) {}
+        template<typename MatrixDerived>
+        explicit MINRES(const EigenBase<MatrixDerived>& A) : Base(A.derived()) {}
         
         /** Destructor. */
         ~MINRES(){}