fixed bodyIdx computation and offSet, needs testing

dune/tectonic/data-structures/friction/globalratestatefriction.hh

@@ -36,11 +36,12 @@ class GlobalRateStateFriction : public GlobalFriction<Matrix, Vector> {
   using ContactCoupling =  DualMortarCoupling<field_type, GridType>;
 
   size_t bodyIndex(const size_t globalIdx) {
-     size_t i=0;
+     size_t i = offSet_.size()-1;
 
-     for (; i<offSet_.size()-1; i++) {
-         if (globalIdx < offSet_[i])
+     for (; i>0; ) {
+         if (globalIdx >= offSet_[i])
              break;
+         i--;
      }
      return i;
   }
@@ -58,7 +59,7 @@ class GlobalRateStateFriction : public GlobalFriction<Matrix, Vector> {
     const auto nBodies = weights.size();
     offSet_.resize(nBodies, 0);
     for (size_t i=1; i<nBodies; i++) {
-        offSet_[i] = weights[i-1].size();
+        offSet_[i] = offSet_[i-1] + weights[i-1].size();
     }
 
     std::vector<std::vector<int>> nonmortarBodies(nBodies); // first index body, second index coupling
@@ -97,16 +98,12 @@ class GlobalRateStateFriction : public GlobalFriction<Matrix, Vector> {
   }
 
   void updateAlpha(const std::vector<ScalarVector>& alpha) override {
+    //print(alpha, "alpha");
     for (size_t j = 0; j < restrictions_.size(); ++j) {
       const auto globalDof = localToGlobal_[j];
       const auto bodyIdx = bodyIndex(globalDof);
+      size_t bodyDof = globalDof - offSet_[bodyIdx];
 
-      size_t bodyDof;
-      if (bodyIdx>0) {
-          bodyDof = globalDof - offSet_[bodyIdx-1];
-      } else {
-          bodyDof = globalDof;
-      }
       restrictions_[j].updateAlpha(alpha[bodyIdx][bodyDof]);
     }
   }