Rework JacobiSVD api / template parameters.

There is now an integer QRPreconditioner template parameter, defaulting to full-piv QR.
Since we have to special-case each QR dec anyway, a template template parameter didn't add much value here.
There is an option NoQRPreconditioner if you know your matrices are already square (auto-detected for fixed-size matrices).

Eigen/src/Core/util/Constants.h

@@ -209,15 +209,6 @@ enum {
   OnTheRight = 2
 };
 
-// options for SVD decomposition
-enum {
-  SkipU = 0x1,
-  SkipV = 0x2,
-  AtLeastAsManyRowsAsCols = 0x4,
-  AtLeastAsManyColsAsRows = 0x8,
-  Square = AtLeastAsManyRowsAsCols | AtLeastAsManyColsAsRows
-};
-
 /* the following could as well be written:
  *   enum NoChange_t { NoChange };
  * but it feels dangerous to disambiguate overloaded functions on enum/integer types.
@@ -252,7 +243,7 @@ enum DecompositionOptions {
   Pivoting            = 0x01, // LDLT,
   NoPivoting          = 0x02, // LDLT,
   ComputeU            = 0x10, // SVD,
-  ComputeR            = 0x20, // SVD,
+  ComputeV            = 0x20, // SVD,
   EigenvaluesOnly     = 0x40, // all eigen solvers
   ComputeEigenvectors = 0x80,  // all eigen solvers
   EigVecMask = EigenvaluesOnly | ComputeEigenvectors,
@@ -262,6 +253,13 @@ enum DecompositionOptions {
   GenEigMask = Ax_lBx | ABx_lx | BAx_lx
 };
 
+enum QRPreconditioners {
+  NoQRPreconditioner,
+  HouseholderQRPreconditioner,
+  ColPivHouseholderQRPreconditioner,
+  FullPivHouseholderQRPreconditioner
+};
+
 /** \brief Enum for reporting the status of a computation.
   */
 enum ComputationInfo {

Eigen/src/Core/util/ForwardDeclarations.h

@@ -170,7 +170,7 @@ template<typename MatrixType> class HouseholderQR;
 template<typename MatrixType> class ColPivHouseholderQR;
 template<typename MatrixType> class FullPivHouseholderQR;
 template<typename MatrixType> class SVD;
-template<typename MatrixType, unsigned int Options = 0> class JacobiSVD;
+template<typename MatrixType, int QRPreconditioner = FullPivHouseholderQRPreconditioner> class JacobiSVD;
 template<typename MatrixType, int UpLo = Lower> class LLT;
 template<typename MatrixType, int UpLo = Lower> class LDLT;
 template<typename VectorsType, typename CoeffsType, int Side=OnTheLeft> class HouseholderSequence;