Changeset 125841 for src/Shapes

Timestamp:

Sep 26, 2012, 5:23:51 PM (13 years ago)

Author:

Frederik Heber <heber@…>

Branches:

Action_Thermostats, Add_AtomRandomPerturbation, Add_FitFragmentPartialChargesAction, Add_RotateAroundBondAction, Add_SelectAtomByNameAction, Added_ParseSaveFragmentResults, AddingActions_SaveParseParticleParameters, Adding_Graph_to_ChangeBondActions, Adding_MD_integration_tests, Adding_ParticleName_to_Atom, Adding_StructOpt_integration_tests, AtomFragments, Automaking_mpqc_open, AutomationFragmentation_failures, Candidate_v1.5.4, Candidate_v1.6.0, Candidate_v1.6.1, ChangeBugEmailaddress, ChangingTestPorts, ChemicalSpaceEvaluator, CombiningParticlePotentialParsing, Combining_Subpackages, Debian_Package_split, Debian_package_split_molecuildergui_only, Disabling_MemDebug, Docu_Python_wait, EmpiricalPotential_contain_HomologyGraph, EmpiricalPotential_contain_HomologyGraph_documentation, Enable_parallel_make_install, Enhance_userguide, Enhanced_StructuralOptimization, Enhanced_StructuralOptimization_continued, Example_ManyWaysToTranslateAtom, Exclude_Hydrogens_annealWithBondGraph, FitPartialCharges_GlobalError, Fix_BoundInBox_CenterInBox_MoleculeActions, Fix_ChargeSampling_PBC, Fix_ChronosMutex, Fix_FitPartialCharges, Fix_FitPotential_needs_atomicnumbers, Fix_ForceAnnealing, Fix_IndependentFragmentGrids, Fix_ParseParticles, Fix_ParseParticles_split_forward_backward_Actions, Fix_PopActions, Fix_QtFragmentList_sorted_selection, Fix_Restrictedkeyset_FragmentMolecule, Fix_StatusMsg, Fix_StepWorldTime_single_argument, Fix_Verbose_Codepatterns, Fix_fitting_potentials, Fixes, ForceAnnealing_goodresults, ForceAnnealing_oldresults, ForceAnnealing_tocheck, ForceAnnealing_with_BondGraph, ForceAnnealing_with_BondGraph_continued, ForceAnnealing_with_BondGraph_continued_betteresults, ForceAnnealing_with_BondGraph_contraction-expansion, FragmentAction_writes_AtomFragments, FragmentMolecule_checks_bonddegrees, GeometryObjects, Gui_Fixes, Gui_displays_atomic_force_velocity, ImplicitCharges, IndependentFragmentGrids, IndependentFragmentGrids_IndividualZeroInstances, IndependentFragmentGrids_IntegrationTest, IndependentFragmentGrids_Sole_NN_Calculation, JobMarket_RobustOnKillsSegFaults, JobMarket_StableWorkerPool, JobMarket_unresolvable_hostname_fix, MoreRobust_FragmentAutomation, ODR_violation_mpqc_open, PartialCharges_OrthogonalSummation, PdbParser_setsAtomName, PythonUI_with_named_parameters, QtGui_reactivate_TimeChanged_changes, Recreated_GuiChecks, Rewrite_FitPartialCharges, RotateToPrincipalAxisSystem_UndoRedo, SaturateAtoms_findBestMatching, SaturateAtoms_singleDegree, StoppableMakroAction, Subpackage_CodePatterns, Subpackage_JobMarket, Subpackage_LinearAlgebra, Subpackage_levmar, Subpackage_mpqc_open, Subpackage_vmg, Switchable_LogView, ThirdParty_MPQC_rebuilt_buildsystem, TrajectoryDependenant_MaxOrder, TremoloParser_IncreasedPrecision, TremoloParser_MultipleTimesteps, TremoloParser_setsAtomName, Ubuntu_1604_changes, stable

Children:

d6203a

Parents:

7e6a1b

git-author:

Michael Ankele <ankele@…> (08/27/12 13:12:27)

git-committer:

Frederik Heber <heber@…> (09/26/12 17:23:51)

Message:

Made Sphere_impl::getHomogeneousPointsOnSurface() more accurate

• TESTFIX: BaseShapesUnitTest now may check whether the desired number of points actually also resulted.
• TESTFIX: Fixing regression test Spherical surface due to changed number of points.

Location:

src/Shapes

Files:

• BaseShapes.cpp (modified) (1 diff)
• unittests/BaseShapesUnitTest.cpp (modified) (1 diff)

src/Shapes/BaseShapes.cpp

@@ -98 +98 @@
 {
   std::vector<Vector> PointsOnSurface;
-
-    double PI=3.14159265358979323846;
-    double a=4*PI/N;
+  if (true) {
+    // Exactly N points but not symmetric.
+
+    // This formula is derived by finding a curve on the sphere that spirals down from
+    // the north pole to the south pole keeping a constant distance between consecutive turns.
+    // The curve is then parametrized by arch length and evaluated in constant intervals.
+    double a = sqrt(N) * 2;
+    for (int i=0; i<N; i++){
+      double t0 = ((double)i + 0.5) / (double)N;
+      double t = (sqrt(t0) - sqrt(1.0 - t0) + 1.0) / 2.0 * M_PI;
+      Vector point;
+      point.Zero();
+      point[0] = sin(t) * sin(t * a);
+      point[1] = sin(t) * cos(t * a);
+      point[2] = cos(t);
+      PointsOnSurface.push_back(point);
+    }
+    ASSERT(PointsOnSurface.size() == N,
+        "Sphere_impl::getHomogeneousPointsOnSurface() did not create "
+        +::toString(N)+" but "+::toString(PointsOnSurface.size())+" points.");
+  } else {
+    // Symmetric but only approximately N points.
+    double a=4*M_PI/N;
     double d= sqrt(a);
-    int Mtheta=int(PI/d);
-    double dtheta=PI/Mtheta;
+    int Mtheta=int(M_PI/d);
+    double dtheta=M_PI/Mtheta;
     double dphi=a/dtheta;
     for (int m=0; m<Mtheta; m++)
     {
-          double theta=PI*(m+0.5)/Mtheta;
-          int Mphi=int(2*PI*sin(theta)/dphi);
-          for (int n=0; n<Mphi;n++)
-          {
-                  double phi= 2*PI*n/Mphi;
-                  Vector point;
-                  point.Zero();
-                  point[0]=sin(theta)*cos(phi);
-                  point[1]=sin(theta)*sin(phi);
-                  point[2]=cos(theta);
-                  PointsOnSurface.push_back(point);
-          }
-    }
-  /*const double dlength = M_PI*(3.-sqrt(5.));
-  double length = 0;
-  const double dz = 2.0/N;
-  double z = 1. - dz/2.;
-  Vector point;
-  for (size_t ka = 0; ka<N; ka++){
-    const double r = sqrt(1.-z*z);
-    point.Zero();
-    point[0] = cos(length)*r;
-    point[1] = sin(length)*r;
-    point[2] = z;
-    PointsOnSurface.push_back(point);
-    z = z - dz;
-    length = length + dlength;*/
-
-//  ASSERT(PointsOnSurface.size() == N,
-//      "Sphere_impl::getHomogeneousPointsOnSurface() did not create "
-//      +::toString(N)+" but "+::toString(PointsOnSurface.size())+" points.");
+      double theta=M_PI*(m+0.5)/Mtheta;
+      int Mphi=int(2*M_PI*sin(theta)/dphi);
+      for (int n=0; n<Mphi;n++)
+      {
+        double phi= 2*M_PI*n/Mphi;
+        Vector point;
+        point.Zero();
+        point[0]=sin(theta)*cos(phi);
+        point[1]=sin(theta)*sin(phi);
+        point[2]=cos(theta);
+        PointsOnSurface.push_back(point);
+      }
+    }
+  }
   return PointsOnSurface;
 }

src/Shapes/unittests/BaseShapesUnitTest.cpp

@@ -652 +652 @@
 void BaseShapesTest::PointsOnSurfaceTest(){
   Shape s = Sphere();
-  const size_t N = 200;
-  std::vector<Vector> PointsOnSurface = s.getHomogeneousPointsOnSurface(N);
-  for (std::vector<Vector>::const_iterator iter = PointsOnSurface.begin(); iter != PointsOnSurface.end(); ++iter) {
-    CPPUNIT_ASSERT(fabs(1. - (*iter).NormSquared()) < MYEPSILON);
+  for (size_t N = 20; N <=200; N+= 45) {
+    std::vector<Vector> PointsOnSurface = s.getHomogeneousPointsOnSurface(N);
+    for (std::vector<Vector>::const_iterator iter = PointsOnSurface.begin(); 
+        iter != PointsOnSurface.end(); 
+        ++iter) {
+      CPPUNIT_ASSERT(fabs(1. - (*iter).NormSquared()) < MYEPSILON);
+    }
+    CPPUNIT_ASSERT_EQUAL( N, PointsOnSurface.size());
   }
-  CPPUNIT_ASSERT_EQUAL((size_t)194, PointsOnSurface.size());
 }