Fixed incorrect checkpointing of reference random number generator

libraries/sfmt/src/SFMT.cpp

@@ -124,14 +124,12 @@ public:
 };
 
 void SFMT::createCheckpoint(std::ostream& stream) {
-    stream.write((char*) &data->baseData, sizeof(data->baseData));
-    stream.write((char*) &data->sfmt, sizeof(data->sfmt));
+    stream.write((char*) data->sfmt, N*sizeof(w128_t));
     stream.write((char*) &data->idx, sizeof(data->idx));
 }
 
 void SFMT::loadCheckpoint(std::istream& stream) {
-    stream.read((char*) &data->baseData, sizeof(data->baseData));
-    stream.read((char*) &data->sfmt, sizeof(data->sfmt));
+    stream.read((char*) data->sfmt, N*sizeof(w128_t));
     stream.read((char*) &data->idx, sizeof(data->idx));
 }
 

platforms/reference/src/SimTKReference/SimTKOpenMMUtilities.cpp

@@ -383,8 +383,11 @@ void SimTKOpenMMUtilities::createCheckpoint(std::ostream& stream) {
 
 void SimTKOpenMMUtilities::loadCheckpoint(std::istream& stream) {
     stream.read((char*) &_randomNumberSeed, sizeof(uint32_t));
+    bool prevInitialized = _randomInitialized;
     stream.read((char*) &_randomInitialized, sizeof(bool));
     if (_randomInitialized) {
+        if (!prevInitialized)
+            init_gen_rand(0, sfmt);
         stream.read((char*) &nextGaussianIsValid, sizeof(bool));
         stream.read((char*) &nextGaussian, sizeof(RealOpenMM));
         sfmt.loadCheckpoint(stream);