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+// This file is part of a joint effort between Eigen, a lightweight C++ template library
+// for linear algebra, and MPFR C++, a C++ interface to MPFR library (http://www.holoborodko.com/pavel/)
+//
+// Copyright (C) 2010 Pavel Holoborodko <pavel@holoborodko.com>
+// Copyright (C) 2010 Konstantin Holoborodko <konstantin@holoborodko.com>
+// Copyright (C) 2010 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/.
+// 
+// Contributors:
+// Brian Gladman, Helmut Jarausch, Fokko Beekhof, Ulrich Mutze, Heinz van Saanen, Pere Constans
+
+#ifndef EIGEN_MPREALSUPPORT_MODULE_H
+#define EIGEN_MPREALSUPPORT_MODULE_H
+
+#include <ctime>
+#include <mpreal.h>
+#include <Eigen/Core>
+
+namespace Eigen {
+  
+  /** \ingroup Unsupported_modules
+    * \defgroup MPRealSupport_Module MPFRC++ Support module
+    *
+    * \code
+    * #include <Eigen/MPRealSupport>
+    * \endcode
+    *
+    * This module provides support for multi precision floating point numbers
+    * via the <a href="http://www.holoborodko.com/pavel/mpfr">MPFR C++</a>
+    * library which itself is built upon <a href="http://www.mpfr.org/">MPFR</a>/<a href="http://gmplib.org/">GMP</a>.
+    *
+    * You can find a copy of MPFR C++ that is known to be compatible in the unsupported/test/mpreal folder.
+    *
+    * Here is an example:
+    *
+\code
+#include <iostream>
+#include <Eigen/MPRealSupport>
+#include <Eigen/LU>
+using namespace mpfr;
+using namespace Eigen;
+int main()
+{
+  // set precision to 256 bits (double has only 53 bits)
+  mpreal::set_default_prec(256);
+  // Declare matrix and vector types with multi-precision scalar type
+  typedef Matrix<mpreal,Dynamic,Dynamic>  MatrixXmp;
+  typedef Matrix<mpreal,Dynamic,1>        VectorXmp;
+
+  MatrixXmp A = MatrixXmp::Random(100,100);
+  VectorXmp b = VectorXmp::Random(100);
+
+  // Solve Ax=b using LU
+  VectorXmp x = A.lu().solve(b);
+  std::cout << "relative error: " << (A*x - b).norm() / b.norm() << std::endl;
+  return 0;
+}
+\endcode
+    *
+    */
+
+  template<> struct NumTraits<mpfr::mpreal>
+    : GenericNumTraits<mpfr::mpreal>
+  {
+    enum {
+      IsInteger = 0,
+      IsSigned = 1,
+      IsComplex = 0,
+      RequireInitialization = 1,
+      ReadCost = 10,
+      AddCost = 10,
+      MulCost = 40
+    };
+
+    typedef mpfr::mpreal Real;
+    typedef mpfr::mpreal NonInteger;
+
+    inline static mpfr::mpreal highest() { return  mpfr::mpreal_max(mpfr::mpreal::get_default_prec()); }
+    inline static mpfr::mpreal lowest()  { return -mpfr::mpreal_max(mpfr::mpreal::get_default_prec()); }
+
+    inline static Real epsilon()
+    {
+      return mpfr::machine_epsilon(mpfr::mpreal::get_default_prec());
+    }
+    inline static Real dummy_precision()
+    {
+      unsigned int weak_prec = ((mpfr::mpreal::get_default_prec()-1)*90)/100;
+      return mpfr::machine_epsilon(weak_prec);
+    }
+  };
+
+namespace internal {
+
+  template<> mpfr::mpreal random<mpfr::mpreal>()
+  {
+#if (MPFR_VERSION >= MPFR_VERSION_NUM(3,0,0))
+    static gmp_randstate_t state;
+    static bool isFirstTime = true;
+
+    if(isFirstTime)
+    {
+      gmp_randinit_default(state);
+      gmp_randseed_ui(state,(unsigned)time(NULL));
+      isFirstTime = false;
+    }
+
+    return mpfr::urandom(state)*2-1;
+#else
+    return mpfr::mpreal(random<double>());
+#endif
+  }
+
+  template<> mpfr::mpreal random<mpfr::mpreal>(const mpfr::mpreal& a, const mpfr::mpreal& b)
+  {
+    return a + (b-a) * random<mpfr::mpreal>();
+  }
+
+  bool isMuchSmallerThan(const mpfr::mpreal& a, const mpfr::mpreal& b, const mpfr::mpreal& prec)
+  {
+    return mpfr::abs(a) <= mpfr::abs(b) * prec;
+  }
+
+  inline bool isApprox(const mpfr::mpreal& a, const mpfr::mpreal& b, const mpfr::mpreal& prec)
+  {
+    return mpfr::abs(a - b) <= (mpfr::min)(mpfr::abs(a), mpfr::abs(b)) * prec;
+  }
+
+  inline bool isApproxOrLessThan(const mpfr::mpreal& a, const mpfr::mpreal& b, const mpfr::mpreal& prec)
+  {
+    return a <= b || isApprox(a, b, prec);
+  }
+  
+  template<> inline long double cast<mpfr::mpreal,long double>(const mpfr::mpreal& x)
+  { return x.toLDouble(); }
+  template<> inline double cast<mpfr::mpreal,double>(const mpfr::mpreal& x)
+  { return x.toDouble(); }
+  template<> inline long cast<mpfr::mpreal,long>(const mpfr::mpreal& x)
+  { return x.toLong(); }
+  template<> inline int cast<mpfr::mpreal,int>(const mpfr::mpreal& x)
+  { return int(x.toLong()); }
+
+} // end namespace internal
+}
+
+#endif // EIGEN_MPREALSUPPORT_MODULE_H