changed to random order

FWI/src/FWINonlinearSolvers.cpp

@@ -149,13 +149,18 @@ public:
     Config::Get("AAORecalculateWFEveryOuter", initialAAO);
     subproblems.resize(data_obs.size());
     nonlinearEvaluations.resize(data_obs.size());
+    std::vector<int> order(data_obs.size());
+    std::iota(order.begin(), order.end(), 1);
+    std::random_device rd;
+    std::mt19937 gen(rd());
+    std::shuffle(order.begin(), order.end(), gen);
     for (int i = 0; i < data_obs.size(); ++i) {
       subproblems[i].resize(1);
       nonlinearEvaluations[i].emplace_back(DGSeismogram(FWD.GetObservationOperator().GetSpaceOp().GetParaDat()),
                             Vectors(FWD.TConf.timeSteps+1,FWD.GetWaveVec()));
       if (initialAAO)
         nonlinearEvaluations[i].back().resetWaveData();
-      subproblems[i][0] = i;
+      subproblems[i][0] = order[i];
     }
   }