[Minuit2] Merge MnTiny into MnMachinePrecision implementation details

The `MnTiny` class was a tiny class that was only used inside
`MnMachinePrecision`.

Author: guitargeek

math/minuit2/CMakeLists.txt

@@ -84,7 +84,6 @@ if(CMAKE_PROJECT_NAME STREQUAL ROOT)
       Minuit2/MnSeedGenerator.h
       Minuit2/MnSimplex.h
       Minuit2/MnStrategy.h
-      Minuit2/MnTiny.h
       Minuit2/MnTraceObject.h
       Minuit2/MnUserCovariance.h
       Minuit2/MnUserFcn.h
@@ -149,7 +148,6 @@ if(CMAKE_PROJECT_NAME STREQUAL ROOT)
       src/MnScan.cxx
       src/MnSeedGenerator.cxx
       src/MnStrategy.cxx
-      src/MnTiny.cxx
       src/MnTraceObject.cxx
       src/MnUserFcn.cxx
       src/MnUserParameterState.cxx

math/minuit2/inc/Minuit2/MnMachinePrecision.h

@@ -52,8 +52,12 @@ class MnMachinePrecision {
    void ComputePrecision();
 
 private:
+   double One() const;
+   double Tiny(double epsp1) const;
+
    double fEpsMac;
    double fEpsMa2;
+   double fOne = 1.;
 };
 
 } // namespace Minuit2

math/minuit2/inc/Minuit2/MnTiny.h

@@ -74,7 +74,6 @@ set(MINUIT2_HEADERS
     MnSeedGenerator.h
     MnSimplex.h
     MnStrategy.h
-    MnTiny.h
     MnTraceObject.h
     MnUserCovariance.h
     MnUserFcn.h
@@ -138,7 +137,6 @@ set(MINUIT2_SOURCES
     MnScan.cxx
     MnSeedGenerator.cxx
     MnStrategy.cxx
-    MnTiny.cxx
     MnTraceObject.cxx
     MnUserFcn.cxx
     MnUserParameterState.cxx

math/minuit2/src/CMakeLists.txt

@@ -8,7 +8,6 @@
  **********************************************************************/
 
 #include "Minuit2/MnMachinePrecision.h"
-#include "Minuit2/MnTiny.h"
 #include <limits>
 
 namespace ROOT {
@@ -39,8 +38,6 @@ void MnMachinePrecision::ComputePrecision()
        fEpsMa2 = 2.*std::sqrt(fEpsMac);
    */
 
-   MnTiny mytiny;
-
    // calculate machine precision
    double epstry = 0.5;
    double epsbak = 0.;
@@ -49,7 +46,7 @@ void MnMachinePrecision::ComputePrecision()
    for (int i = 0; i < 100; i++) {
       epstry *= 0.5;
       epsp1 = one + epstry;
-      epsbak = mytiny(epsp1);
+      epsbak = Tiny(epsp1);
       if (epsbak < epstry) {
          fEpsMac = 8. * epstry;
          fEpsMa2 = 2. * std::sqrt(fEpsMac);
@@ -58,6 +55,18 @@ void MnMachinePrecision::ComputePrecision()
    }
 }
 
+double MnMachinePrecision::One() const
+{
+   return fOne;
+}
+
+double MnMachinePrecision::Tiny(double epsp1) const
+{
+   // evaluate minimal difference between two floating points
+   double result = epsp1 - One();
+   return result;
+}
+
 } // namespace Minuit2
 
 } // namespace ROOT