Add inverse mapping function (idaholab#410)

snschune · Jan 7, 2020 · dd815ec · dd815ec
1 parent f808511
commit dd815ec
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Showing 7 changed files with 62 additions and 5 deletions.
diff --git a/include/utils/PolyatomicDamageEnergyFunction.h b/include/utils/PolyatomicDamageEnergyFunction.h
@@ -39,10 +39,17 @@ class PolyatomicDamageEnergyFunction : public PolyatomicDisplacementFunctionBase
   Real _taylor_series_threshold = 1e2;
 
 protected:
+  /// override the mapIndex function: flattens ijl to single index n
   unsigned int mapIndex(unsigned int i, unsigned int /*j*/, unsigned int /*l*/) const override
   {
     return i;
   };
+
+  /// override the inverseMapIndex function: retrieves n given ijk
+  void inverseMapIndex(unsigned int n,
+                       unsigned int & i,
+                       unsigned int & j,
+                       unsigned int & l) const override;
 };
 
 #endif // GSL_ENABLED
diff --git a/include/utils/PolyatomicDisplacementDerivativeFunction.h b/include/utils/PolyatomicDisplacementDerivativeFunction.h
@@ -39,12 +39,18 @@ class PolyatomicDisplacementDerivativeFunction : public PolyatomicDisplacementFu
   Real source(Real energy, unsigned int i, unsigned int j, unsigned int l);
 
 protected:
-  /// maps triple index theta_ijl to single theta_n; l runs faster than j runs faster than i
+  /// override the mapIndex function: flattens ijl to single index n
   unsigned int mapIndex(unsigned int i, unsigned int j, unsigned int l) const override
   {
     return i + j * _n_species + l * _n_species * _n_species;
   };
 
+  /// override the inverseMapIndex function: retrieves n given ijk
+  void inverseMapIndex(unsigned int n,
+                       unsigned int & i,
+                       unsigned int & j,
+                       unsigned int & l) const override;
+
   /// the source term in the NRT equatons for the derivative requires the solution of the equations themselves
   const PolyatomicDisplacementFunction * _net_displacement_function;
 };

diff --git a/include/utils/PolyatomicDisplacementFunction.h b/include/utils/PolyatomicDisplacementFunction.h
@@ -32,12 +32,18 @@ class PolyatomicDisplacementFunction : public PolyatomicDisplacementFunctionBase
   Real integralTypeII(Real energy, unsigned int i, unsigned int j, unsigned int k) const;
 
 protected:
-  /// maps double index nu_ij to single index nu_n; j runs faster than i
+  /// override the mapIndex function: flattens ijl to single index n
   unsigned int mapIndex(unsigned int i, unsigned int j, unsigned int /*l*/) const override
   {
     return i + j * _n_species;
   };
 
+  /// override the inverseMapIndex function: retrieves n given ijk
+  void inverseMapIndex(unsigned int n,
+                       unsigned int & i,
+                       unsigned int & j,
+                       unsigned int & l) const override;
+
   /// is the total damage function computed
   bool _total_displacement_function;
 };

diff --git a/include/utils/PolyatomicDisplacementFunctionBase.h b/include/utils/PolyatomicDisplacementFunctionBase.h
@@ -57,7 +57,8 @@ class PolyatomicDisplacementFunctionBase
   ///@}
 
   /// linear interpolation of the damage function
-  Real linearInterpolation(Real energy, unsigned int i, unsigned int j = 0, unsigned int l = 0) const;
+  Real
+  linearInterpolation(Real energy, unsigned int i, unsigned int j = 0, unsigned int l = 0) const;
 
   /// gets stopping power for a given species and energy; non-const because it uses _ions so no need to construct ion
   Real stoppingPower(unsigned int species, Real energy);
@@ -72,6 +73,10 @@ class PolyatomicDisplacementFunctionBase
   /// this function flattens the arrays i, j, l to a single index
   virtual unsigned int mapIndex(unsigned int i, unsigned int j, unsigned int l) const = 0;
 
+  /// this function unflattens n to indices i, j, l
+  virtual void
+  inverseMapIndex(unsigned int n, unsigned int & i, unsigned int & j, unsigned int & l) const = 0;
+
   /// computes the integral int_0^t dT T * d(sigma_ij) / dT for species combination i, j and small t
   Real
   weightedScatteringIntegral(Real energy, Real energy_limit, unsigned int i, unsigned int j) const;
@@ -94,7 +99,6 @@ class PolyatomicDisplacementFunctionBase
   Real linearInterpolationHelper(
       Real energy, unsigned int index, unsigned int i, unsigned int j, unsigned int l) const;
 
-
   /// damage function type [nij and gij, respectively in PK JNM 101, 1981; or nu_i JNM 88, (1980)]
   nrt_type _damage_function_type;
 

diff --git a/src/utils/PolyatomicDamageEnergyFunction.C b/src/utils/PolyatomicDamageEnergyFunction.C
@@ -156,10 +156,21 @@ PolyatomicDamageEnergyFunction::integralTypeII(Real energy, unsigned int i, unsi
     {
       Real recoil_energy = scale * (_quad_points[qp] + 1) + lower;
       integral += scale * _quad_weights[qp] * scatteringCrossSection(i, j, energy, recoil_energy) *
-                  (linearInterpolation( energy - recoil_energy, i) - current_value);
+                  (linearInterpolation(energy - recoil_energy, i) - current_value);
     }
   }
   return integral;
 }
 
+void
+PolyatomicDamageEnergyFunction::inverseMapIndex(unsigned int n,
+                                                unsigned int & i,
+                                                unsigned int & j,
+                                                unsigned int & l) const
+{
+  i = n;
+  j = 0;
+  l = 0;
+}
+
 #endif
diff --git a/src/utils/PolyatomicDisplacementDerivativeFunction.C b/src/utils/PolyatomicDisplacementDerivativeFunction.C
@@ -183,4 +183,16 @@ PolyatomicDisplacementDerivativeFunction::source(Real energy,
          d_net_dE * stoppingPowerDerivative(i, l, energy);
 }
 
+void
+PolyatomicDisplacementDerivativeFunction::inverseMapIndex(unsigned int n,
+                                                          unsigned int & i,
+                                                          unsigned int & j,
+                                                          unsigned int & l) const
+{
+  unsigned int t = n % (_n_species * _n_species);
+  i = t % _n_species;
+  j = (t - i) / _n_species;
+  l = (n - t) / (_n_species * _n_species);
+}
+
 #endif
diff --git a/src/utils/PolyatomicDisplacementFunction.C b/src/utils/PolyatomicDisplacementFunction.C
@@ -161,4 +161,15 @@ PolyatomicDisplacementFunction::integralTypeII(Real energy,
   return integral;
 }
 
+void
+PolyatomicDisplacementFunction::inverseMapIndex(unsigned int n,
+                                                unsigned int & i,
+                                                unsigned int & j,
+                                                unsigned int & l) const
+{
+  i = n % _n_species;
+  j = (n - i) / _n_species;
+  l = 0;
+}
+
 #endif