The Drude and RPMD plugins both also use random numbers -- change default seed

to 0 here as well.

plugins/drude/openmmapi/include/openmm/DrudeLangevinIntegrator.h

@@ -142,6 +142,10 @@ public:
      * the other hand, no guarantees are made about the behavior of simulations that use the same seed.
      * In particular, Platforms are permitted to use non-deterministic algorithms which produce different
      * results on successive runs, even if those runs were initialized identically.
+     *
+     * If seed is set to 0 (which is the default value assigned), a unique seed is chosen when a Context
+     * is created from this Force. This is done to ensure that each Context receives unique random seeds
+     * without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

plugins/drude/openmmapi/src/DrudeLangevinIntegrator.cpp

@@ -33,7 +33,6 @@
 #include "openmm/Context.h"
 #include "openmm/OpenMMException.h"
 #include "openmm/internal/ContextImpl.h"
-#include "openmm/internal/OSRngSeed.h"
 #include "openmm/DrudeKernels.h"
 #include <ctime>
 #include <string>
@@ -49,7 +48,7 @@ DrudeLangevinIntegrator::DrudeLangevinIntegrator(double temperature, double fric
     setDrudeFriction(drudeFrictionCoeff);
     setStepSize(stepSize);
     setConstraintTolerance(1e-5);
-    setRandomNumberSeed(osrngseed());
+    setRandomNumberSeed(0);
 }
 
 void DrudeLangevinIntegrator::initialize(ContextImpl& contextRef) {

plugins/rpmd/openmmapi/include/openmm/RPMDIntegrator.h

@@ -155,6 +155,10 @@ public:
      * the other hand, no guarantees are made about the behavior of simulations that use the same seed.
      * In particular, Platforms are permitted to use non-deterministic algorithms which produce different
      * results on successive runs, even if those runs were initialized identically.
+     *
+     * If seed is set to 0 (which is the default value assigned), a unique seed is chosen when a Context
+     * is created from this Force. This is done to ensure that each Context receives unique random seeds
+     * without you needing to set them explicitly.
      */
     void setRandomNumberSeed(int seed) {
         randomNumberSeed = seed;

plugins/rpmd/openmmapi/src/RPMDIntegrator.cpp

@@ -33,7 +33,6 @@
 #include "openmm/Context.h"
 #include "openmm/OpenMMException.h"
 #include "openmm/internal/ContextImpl.h"
-#include "openmm/internal/OSRngSeed.h"
 #include "openmm/RpmdKernels.h"
 #include "SimTKOpenMMRealType.h"
 #include <cmath>
@@ -48,7 +47,7 @@ RPMDIntegrator::RPMDIntegrator(int numCopies, double temperature, double frictio
     setFriction(frictionCoeff);
     setStepSize(stepSize);
     setConstraintTolerance(1e-5);
-    setRandomNumberSeed(osrngseed());
+    setRandomNumberSeed(0);
 }
 
 RPMDIntegrator::RPMDIntegrator(int numCopies, double temperature, double frictionCoeff, double stepSize) :
@@ -57,7 +56,7 @@ RPMDIntegrator::RPMDIntegrator(int numCopies, double temperature, double frictio
     setFriction(frictionCoeff);
     setStepSize(stepSize);
     setConstraintTolerance(1e-5);
-    setRandomNumberSeed(osrngseed());
+    setRandomNumberSeed(0);
 }
 
 void RPMDIntegrator::initialize(ContextImpl& contextRef) {