Computational improvements to static optimization

Applications/Analyze/test/testStaticOptimization.cpp

@@ -265,4 +265,14 @@ void testArm26DisabledMuscles() {
     ASSERT_EQUAL(forces.getColumnLabels().findIndex("TRIlat"), -1);
     ASSERT_EQUAL(forces.getColumnLabels().findIndex("TRImed"), -1);
 
+    StaticOptimization& statOpt =(StaticOptimization&)model.getAnalysisSet().get("StaticOptimization");
+    Storage* statesDerivativeStore = statOpt.getStatesDerivativeStore();
+    const Storage* statesStore = statOpt._statesStore;
+    Array<double> time;
+    Array<double> time_d;
+    int nt = statesStore->getTimeColumn(time);
+    int nt_d = statesDerivativeStore->getTimeColumn(time_d);
+    ASSERT_EQUAL(nt, nt_d);
+    ASSERT_EQUAL<Array<double>>(time, time_d, std::numeric_limits<double>::epsilon());
+
 }

CHANGELOG.md

@@ -89,6 +89,7 @@ v4.6
 - Fixed a bug where `DeGrooteFregly2016Muscle::getBoundsNormalizedFiberLength()` was returning
   tendon force bounds rather than fiber length bounds. (#4040)
 - Fixed bugs in `PolynomialPathFitter` when too few coordinate samples were provided. (#4039)
+- In `StaticOptimization`, state derivatives are now pre-calculated at the time points of the original data, rather than calculated during optimization from splines. This change reduces computational time by as much as 25%. (#4037)
 - Exposed the "dissipated energy" state variable allocated by the `SimTK::Force::LinearBushing` that is internal to `BushingForce`. 
   This change fixed a bug in Moco where adding a `BushingForce` led to a segfault due to a mismatch between the size of the 
   auxiliary state vector reserved by Moco and `SimTK::State::getZ()`. (#4054)