fix a number of compiler errors and warnings with gcc 4.3. There was a missing

#include<algorithm> so I'm not sure how it compiled at all for you :)

Eigen/Regression

@@ -2,6 +2,7 @@
 #define EIGEN_REGRESSION_MODULE_H
 
 #include "LU"
+#include "QR"
 
 namespace Eigen {
 

Eigen/Sparse

@@ -4,8 +4,9 @@
 #include "Core"
 #include <vector>
 #include <map>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdlib>
+#include <cstring>
+#include <algorithm>
 
 namespace Eigen {
 

Eigen/src/Sparse/HashMatrix.h

@@ -71,7 +71,7 @@ class HashMatrix : public SparseMatrixBase<HashMatrix<_Scalar, _Flags> >
 
   public:
 
-    inline void startFill(int reserveSize = 1000) {}
+    inline void startFill(int /*reserveSize = 1000 --- currenty unused, don't generate a warning*/) {}
 
     inline Scalar& fill(int row, int col) { return coeffRef(row, col); }
 

Eigen/src/Sparse/SparseArray.h

@@ -51,6 +51,7 @@ template<typename Scalar> class SparseArray
       resize(other.size());
       memcpy(m_values, other.m_values, m_size * sizeof(Scalar));
       memcpy(m_indices, other.m_indices, m_size * sizeof(int));
+      return *this;
     }
 
     void swap(SparseArray& other)

Eigen/src/Sparse/SparseMatrix.h

@@ -213,8 +213,8 @@ class SparseMatrix : public SparseMatrixBase<SparseMatrix<_Scalar, _Flags> >
         for (int j=0; j<=m_outerSize; ++j)
           m_outerIndex[j] = other.m_outerIndex[j];
         m_data = other.m_data;
-        return *this;
       }
+      return *this;
     }
 
     template<typename OtherDerived>

Eigen/src/Sparse/SparseMatrixBase.h

@@ -73,8 +73,10 @@ class SparseMatrixBase : public MatrixBase<Derived>
         {
           Scalar v = it.value();
           if (v!=Scalar(0))
+          {
             if (OtherDerived::Flags & RowMajorBit) temp.fill(j,it.index()) = v;
             else temp.fill(it.index(),j) = v;
+          }
         }
       }
       temp.endFill();
@@ -100,8 +102,10 @@ class SparseMatrixBase : public MatrixBase<Derived>
           {
             Scalar v = it.value();
             if (v!=Scalar(0))
+            {
               if (RowMajor) derived().fill(j,it.index()) = v;
               else derived().fill(it.index(),j) = v;
+            }
           }
         }
         derived().endFill();

test/sparse.cpp

@@ -61,7 +61,7 @@ template<typename Scalar> void sparse()
   VERIFY(nonzeroCoords.size()>0 && "re-run the test");
 
   // test coeff and coeffRef
-  for (int i=0; i<zeroCoords.size(); ++i)
+  for (int i=0; i<(int)zeroCoords.size(); ++i)
   {
     VERIFY_IS_MUCH_SMALLER_THAN( m.coeff(zeroCoords[i].x(),zeroCoords[i].y()), eps );
     VERIFY_RAISES_ASSERT( m.coeffRef(zeroCoords[0].x(),zeroCoords[0].y()) = 5 );