Port changes from the main repository

Use cuCtxPushCurrent() and cuCtxPopCurrent() for selecting CUDA context

    https://github.com/openmm/openmm/pull/3258

Fixed uninitialized memory access

    https://github.com/openmm/openmm/issues/3392
    https://github.com/openmm/openmm/pull/3399

Fixed potential invalid memory access

    See https://github.com/openmm/openmm/pull/3428

Improved temperature reporting for Drude particles

    https://github.com/openmm/openmm/pull/3486
    https://github.com/openmm/openmm/commit/a5e42f5

Fixed race condition with multiple GPUs

    https://github.com/openmm/openmm/commit/6fb1c8a41edff980862750bc086f6a204eb50941

Use blocking sync when creating events

    https://github.com/openmm/openmm/commit/fe21d5ee4f14673a4ea38b7244991772a64ceec2

Very minor optimizations

    https://github.com/openmm/openmm/commit/109f6b2535da4e0c0dd88007d6ca06b4add2ce81

Use PocketFFT

    https://github.com/openmm/openmm/commit/1dac981a63300a2a53a7925f570995914f7163ed

Improved logic for deciding when to reorder atoms

    https://github.com/openmm/openmm/commit/48664a1f1a4490a4dabc277757545ac070e7b898

Ensure valid atom order after loading a checkpoint

    https://github.com/openmm/openmm/commit/a056d5a3754e193105409afa12c9f0c9a2d972a2

Improve performance running on multiple GPUs

    https://github.com/openmm/openmm/commit/0c82c2647de98da5c6dab7bf7a7b8b19705aadc0

Fixed errors when running on multiple GPUs

    https://github.com/openmm/openmm/commit/ed9df876d43c037c08d4762721e73e5caae086d9

Optimized reducing energy

    https://github.com/openmm/openmm/commit/2975f44

platforms/hip/include/HipArray.h

@@ -9,8 +9,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2009-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2009-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -56,7 +56,7 @@ public:
      * @param name              the name of the array
      */
     template <class T>
-    static HipArray* create(HipContext& context, int size, const std::string& name) {
+    static HipArray* create(HipContext& context, size_t size, const std::string& name) {
         return new HipArray(context, size, sizeof(T), name);
     }
     /**
@@ -72,7 +72,7 @@ public:
      * @param elementSize       the size of each element in bytes
      * @param name              the name of the array
      */
-    HipArray(HipContext& context, int size, int elementSize, const std::string& name);
+    HipArray(HipContext& context, size_t size, int elementSize, const std::string& name);
     ~HipArray();
     /**
      * Initialize this object.
@@ -82,7 +82,7 @@ public:
      * @param elementSize       the size of each element in bytes
      * @param name              the name of the array
      */
-    void initialize(ComputeContext& context, int size, int elementSize, const std::string& name);
+    void initialize(ComputeContext& context, size_t size, int elementSize, const std::string& name);
     /**
      * Initialize this object.  The template argument is the data type of each array element.
      *
@@ -91,13 +91,13 @@ public:
      * @param name              the name of the array
      */
     template <class T>
-    void initialize(ComputeContext& context, int size, const std::string& name) {
+    void initialize(ComputeContext& context, size_t size, const std::string& name) {
         initialize(context, size, sizeof(T), name);
     }
     /**
      * Recreate the internal storage to have a different size.
      */
-    void resize(int size);
+    void resize(size_t size);
     /**
      * Get whether this array has been initialized.
      */
@@ -107,7 +107,7 @@ public:
     /**
      * Get the number of elements in the array.
      */
-    int getSize() const {
+    size_t getSize() const {
         return size;
     }
     /**
@@ -183,7 +183,8 @@ public:
 private:
     HipContext* context;
     hipDeviceptr_t pointer;
-    int size, elementSize;
+    size_t size;
+    int elementSize;
     bool ownsMemory;
     std::string name;
 };

platforms/hip/include/HipContext.h

@@ -39,6 +39,7 @@
 
 
 #include <map>
+#include <stack>
 #include <string>
 #include <utility>
 #define __CL_ENABLE_EXCEPTIONS
@@ -99,10 +100,20 @@ public:
         return contextIsValid;
     }
     /**
-     * Set the hipCtx_t associated with this object to be the current context.  If the context is not
+     * Set the device associated with this object to be the current device.  If the context is not
      * valid, this returns without doing anything.
      */
     void setAsCurrent();
+    /**
+     * Push the device associated with this object to be the current device.  If the context is not
+     * valid, this returns without doing anything.
+     */
+    void pushAsCurrent();
+    /**
+     * Pop the device associated with this object off the stack of contexts.  If the context is not
+     * valid, this returns without doing anything.
+     */
+    void popAsCurrent();
     /**
      * Get the hipDevice_t associated with this object.
      */
@@ -582,6 +593,10 @@ public:
      * expense of reduced simulation performance.
      */
     void flushQueue();
+    /**
+     * Get the flags that should be used when creating hipEvent_t objects.
+     */
+    unsigned int getEventFlags();
     /**
      * Get the flags that should be used when allocating pinned host memory.
      */
@@ -610,6 +625,7 @@ private:
     std::map<std::string, std::string> compilationDefines;
     std::vector<hipModule_t> loadedModules;
     hipDevice_t device;
+    std::stack<hipDevice_t> outerScopeDevices;
     hipStream_t currentStream;
     hipFunction_t clearBufferKernel;
     hipFunction_t clearTwoBuffersKernel;

platforms/hip/include/HipKernels.h

@@ -9,8 +9,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2008-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2008-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -109,6 +109,18 @@ public:
      * @param context    the context in which to execute this kernel
      */
     void setTime(ContextImpl& context, double time);
+    /**
+     * Get the current step count
+     *
+     * @param context    the context in which to execute this kernel
+     */
+    long long getStepCount(const ContextImpl& context) const;
+    /**
+     * Set the current step count
+     *
+     * @param context    the context in which to execute this kernel
+     */
+    void setStepCount(const ContextImpl& context, long long count);
     /**
      * Get the positions of all particles.
      *
@@ -133,6 +145,15 @@ public:
      * @param velocities  a vector containg the particle velocities
      */
     void setVelocities(ContextImpl& context, const std::vector<Vec3>& velocities);
+    /**
+     * Compute velocities, shifted in time to account for a leapfrog integrator.  The shift
+     * is based on the most recently computed forces.
+     * 
+     * @param context     the context in which to execute this kernel
+     * @param timeShift   the amount by which to shift the velocities in time
+     * @param velocities  the shifted velocities are returned in this
+     */
+    void computeShiftedVelocities(ContextImpl& context, double timeShift, std::vector<Vec3>& velocities);
     /**
      * Get the current forces on all particles.
      *

platforms/hip/include/HipNonbondedUtilities.h

@@ -9,8 +9,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2009-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2009-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -339,7 +339,7 @@ private:
     HipArray rebuildNeighborList;
     HipSort* blockSorter;
     hipEvent_t downloadCountEvent;
-    int* pinnedCountBuffer;
+    unsigned int* pinnedCountBuffer;
     std::vector<void*> forceArgs, findBlockBoundsArgs, sortBoxDataArgs, findInteractingBlocksArgs;
     std::vector<std::vector<int> > atomExclusions;
     std::vector<ParameterInfo> parameters;
@@ -349,8 +349,9 @@ private:
     std::map<int, std::string> groupKernelSource;
     double lastCutoff;
     bool useCutoff, usePeriodic, anyExclusions, usePadding, forceRebuildNeighborList, canUsePairList;
-    int startTileIndex, startBlockIndex, numBlocks, maxTiles, maxSinglePairs, numTilesInBatch, maxExclusions;
+    int startTileIndex, startBlockIndex, numBlocks, numTilesInBatch, maxExclusions;
     int numForceThreadBlocks, forceThreadBlockSize, findInteractingBlocksThreadBlockSize, numAtoms, groupFlags;
+    unsigned int maxTiles, maxSinglePairs, tilesAfterReorder;
     long long numTiles;
     std::string kernelSource;
 };

platforms/hip/include/HipParallelKernels.h

@@ -91,7 +91,9 @@ private:
     long long* pinnedForceBuffer;
     hipFunction_t sumKernel;
     hipEvent_t event;
-    hipStream_t peerCopyStream;
+    std::vector<hipEvent_t> peerCopyEvent;
+    std::vector<hipEvent_t> peerCopyEventLocal;
+    std::vector<hipStream_t> peerCopyStream;
 };
 
 /**

platforms/hip/include/HipPlatform.h

@@ -126,8 +126,8 @@ public:
     std::vector<HipContext*> contexts;
     std::vector<double> contextEnergy;
     bool hasInitializedContexts, removeCM, peerAccessSupported, useCpuPme, disablePmeStream, deterministicForces;
-    int cmMotionFrequency;
-    int stepCount, computeForceCount;
+    int cmMotionFrequency, computeForceCount;
+    long long stepCount;
     double time;
     std::map<std::string, std::string> propertyValues;
     ThreadPool threads;

platforms/hip/src/HipArray.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2012-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2012-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -27,6 +27,7 @@
 
 #include "HipArray.h"
 #include "HipContext.h"
+#include "openmm/common/ContextSelector.h"
 #include <iostream>
 #include <sstream>
 #include <vector>
@@ -36,13 +37,13 @@ using namespace OpenMM;
 HipArray::HipArray() : pointer(0), ownsMemory(false) {
 }
 
-HipArray::HipArray(HipContext& context, int size, int elementSize, const std::string& name) : pointer(0) {
+HipArray::HipArray(HipContext& context, size_t size, int elementSize, const std::string& name) : pointer(0) {
     initialize(context, size, elementSize, name);
 }
 
 HipArray::~HipArray() {
     if (pointer != 0 && ownsMemory && context->getContextIsValid()) {
-        context->setAsCurrent();
+        ContextSelector selector(*context);
         hipError_t result = hipFree(pointer);
         if (result != hipSuccess) {
             std::stringstream str;
@@ -52,7 +53,7 @@ HipArray::~HipArray() {
     }
 }
 
-void HipArray::initialize(ComputeContext& context, int size, int elementSize, const std::string& name) {
+void HipArray::initialize(ComputeContext& context, size_t size, int elementSize, const std::string& name) {
     if (this->pointer != 0)
         throw OpenMMException("HipArray has already been initialized");
     this->context = &dynamic_cast<HipContext&>(context);
@@ -60,6 +61,7 @@ void HipArray::initialize(ComputeContext& context, int size, int elementSize, co
     this->elementSize = elementSize;
     this->name = name;
     ownsMemory = true;
+    ContextSelector selector(*this->context);
     hipError_t result = hipMalloc(&pointer, size*elementSize);
     if (result != hipSuccess) {
         std::stringstream str;
@@ -68,11 +70,12 @@ void HipArray::initialize(ComputeContext& context, int size, int elementSize, co
     }
 }
 
-void HipArray::resize(int size) {
+void HipArray::resize(size_t size) {
     if (pointer == 0)
         throw OpenMMException("HipArray has not been initialized");
     if (!ownsMemory)
         throw OpenMMException("Cannot resize an array that does not own its storage");
+    ContextSelector selector(*context);
     hipError_t result = hipFree(pointer);
     if (result != hipSuccess) {
         std::stringstream str;

platforms/hip/src/HipContext.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2009-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2009-2023 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2023 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -39,6 +39,7 @@
 #include "HipProgram.h"
 #include "HipFFT3D.h"
 #include "openmm/common/ComputeArray.h"
+#include "openmm/common/ContextSelector.h"
 #include "SHA1.h"
 #include "openmm/Platform.h"
 #include "openmm/System.h"
@@ -184,13 +185,15 @@ HipContext::HipContext(const System& system, int deviceIndex, bool useBlockingSy
     }
 
     contextIsValid = true;
+    ContextSelector selector(*this);
     if (contextIndex > 0) {
         int canAccess;
         CHECK_RESULT(hipDeviceCanAccessPeer(&canAccess, getDevice(), platformData.contexts[0]->getDevice()));
         if (canAccess) {
-            platformData.contexts[0]->setAsCurrent();
-            CHECK_RESULT(hipDeviceEnablePeerAccess(getDevice(), 0));
-            setAsCurrent();
+            {
+                ContextSelector selector2(*platformData.contexts[0]);
+                CHECK_RESULT(hipDeviceEnablePeerAccess(getDevice(), 0));
+            }
             CHECK_RESULT(hipDeviceEnablePeerAccess(platformData.contexts[0]->getDevice(), 0));
         }
     }
@@ -345,7 +348,7 @@ HipContext::HipContext(const System& system, int deviceIndex, bool useBlockingSy
 }
 
 HipContext::~HipContext() {
-    setAsCurrent();
+    pushAsCurrent();
     for (auto force : forces)
         delete force;
     for (auto listener : reorderListeners)
@@ -366,28 +369,29 @@ HipContext::~HipContext() {
         delete nonbonded;
     for (auto module : loadedModules)
         hipModuleUnload(module);
+    popAsCurrent();
     contextIsValid = false;
 }
 
 void HipContext::initialize() {
-    hipSetDevice(device);
+    ContextSelector selector(*this);
     string errorMessage = "Error initializing Context";
     int numEnergyBuffers = max(numThreadBlocks*ThreadBlockSize, nonbonded->getNumEnergyBuffers());
     if (useDoublePrecision) {
         energyBuffer.initialize<double>(*this, numEnergyBuffers, "energyBuffer");
-        energySum.initialize<double>(*this, 1, "energySum");
+        energySum.initialize<double>(*this, multiprocessors, "energySum");
         int pinnedBufferSize = max(paddedNumAtoms*4, numEnergyBuffers);
         CHECK_RESULT(hipHostMalloc(&pinnedBuffer, pinnedBufferSize*sizeof(double), getHostMallocFlags()));
     }
     else if (useMixedPrecision) {
         energyBuffer.initialize<double>(*this, numEnergyBuffers, "energyBuffer");
-        energySum.initialize<double>(*this, 1, "energySum");
+        energySum.initialize<double>(*this, multiprocessors, "energySum");
         int pinnedBufferSize = max(paddedNumAtoms*4, numEnergyBuffers);
         CHECK_RESULT(hipHostMalloc(&pinnedBuffer, pinnedBufferSize*sizeof(double), getHostMallocFlags()));
     }
     else {
         energyBuffer.initialize<float>(*this, numEnergyBuffers, "energyBuffer");
-        energySum.initialize<float>(*this, 1, "energySum");
+        energySum.initialize<float>(*this, multiprocessors, "energySum");
         int pinnedBufferSize = max(paddedNumAtoms*6, numEnergyBuffers);
         CHECK_RESULT(hipHostMalloc(&pinnedBuffer, pinnedBufferSize*sizeof(float), getHostMallocFlags()));
     }
@@ -423,6 +427,29 @@ void HipContext::setAsCurrent() {
         hipSetDevice(device);
 }
 
+void HipContext::pushAsCurrent() {
+    if (contextIsValid) {
+        // Emulate cuCtxPushCurrent's behavior
+        hipDevice_t outerScopeDevice;
+        hipGetDevice(&outerScopeDevice);
+        outerScopeDevices.push(outerScopeDevice);
+        if (device != outerScopeDevice) {
+            hipSetDevice(device);
+        }
+    }
+}
+
+void HipContext::popAsCurrent() {
+    if (contextIsValid) {
+        // Emulate cuCtxPopCurrent's behavior
+        hipDevice_t outerScopeDevice = outerScopeDevices.top();
+        outerScopeDevices.pop();
+        if (outerScopeDevice != device) {
+            hipSetDevice(outerScopeDevice);
+        }
+    }
+}
+
 string HipContext::getTempFileName() const {
     stringstream tempFileName;
     tempFileName << tempDir;
@@ -784,12 +811,18 @@ double HipContext::reduceEnergy() {
     int bufferSize = energyBuffer.getSize();
     int workGroupSize = getMaxThreadBlockSize();
     void* args[] = {&energyBuffer.getDevicePointer(), &energySum.getDevicePointer(), &bufferSize, &workGroupSize};
-    executeKernel(reduceEnergyKernel, args, workGroupSize, workGroupSize, workGroupSize*energyBuffer.getElementSize());
+    executeKernel(reduceEnergyKernel, args, workGroupSize*energySum.getSize(), workGroupSize, workGroupSize*energyBuffer.getElementSize());
     energySum.download(pinnedBuffer);
-    if (getUseDoublePrecision() || getUseMixedPrecision())
-        return *((double*) pinnedBuffer);
-    else
-        return *((float*) pinnedBuffer);
+    double result = 0;
+    if (getUseDoublePrecision() || getUseMixedPrecision()) {
+        for (int i = 0; i < energySum.getSize(); i++)
+            result += ((double*) pinnedBuffer)[i];
+    }
+    else {
+        for (int i = 0; i < energySum.getSize(); i++)
+            result += ((float*) pinnedBuffer)[i];
+    }
+    return result;
 }
 
 void HipContext::setCharges(const vector<double>& charges) {
@@ -850,6 +883,13 @@ vector<int> HipContext::getDevicePrecedence() {
     return precedence;
 }
 
+unsigned int HipContext::getEventFlags() {
+    unsigned int flags = hipEventDisableTiming;
+    if (useBlockingSync)
+        flags += hipEventBlockingSync;
+    return flags;
+}
+
 unsigned int HipContext::getHostMallocFlags() {
 #ifdef WIN32
     return hipHostMallocDefault;

platforms/hip/src/HipEvent.cpp

@@ -31,7 +31,7 @@
 using namespace OpenMM;
 
 HipEvent::HipEvent(HipContext& context) : context(context), eventCreated(false) {
-    hipError_t result = hipEventCreateWithFlags(&event, hipEventDisableTiming);
+    hipError_t result = hipEventCreateWithFlags(&event, context.getEventFlags());
     if (result != hipSuccess)
         throw OpenMMException("Error creating HIP event:"+HipContext::getErrorString(result));
     eventCreated = true;

platforms/hip/src/HipIntegrationUtilities.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2009-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2009-2021 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2021 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -27,6 +27,7 @@
 
 #include "HipIntegrationUtilities.h"
 #include "HipContext.h"
+#include "openmm/common/ContextSelector.h"
 
 using namespace OpenMM;
 using namespace std;
@@ -41,13 +42,13 @@ using namespace std;
 
 HipIntegrationUtilities::HipIntegrationUtilities(HipContext& context, const System& system) : IntegrationUtilities(context, system),
         ccmaConvergedMemory(NULL) {
-        CHECK_RESULT2(hipEventCreateWithFlags(&ccmaEvent, hipEventDisableTiming), "Error creating event for CCMA");
+        CHECK_RESULT2(hipEventCreateWithFlags(&ccmaEvent, context.getEventFlags()), "Error creating event for CCMA");
         CHECK_RESULT2(hipHostMalloc((void**) &ccmaConvergedMemory, sizeof(int), context.getHostMallocFlags()), "Error allocating pinned memory");
         CHECK_RESULT2(hipHostGetDevicePointer(&ccmaConvergedDeviceMemory, ccmaConvergedMemory, 0), "Error getting device address for pinned memory");
 }
 
 HipIntegrationUtilities::~HipIntegrationUtilities() {
-    context.setAsCurrent();
+    ContextSelector selector(context);
     if (ccmaConvergedMemory != NULL) {
         hipHostFree(ccmaConvergedMemory);
         hipEventDestroy(ccmaEvent);
@@ -67,6 +68,7 @@ HipArray& HipIntegrationUtilities::getStepSize() {
 }
 
 void HipIntegrationUtilities::applyConstraintsImpl(bool constrainVelocities, double tol) {
+    ContextSelector selector(context);
     ComputeKernel settleKernel, shakeKernel, ccmaForceKernel;
     if (constrainVelocities) {
         settleKernel = settleVelKernel;
@@ -132,6 +134,7 @@ void HipIntegrationUtilities::applyConstraintsImpl(bool constrainVelocities, dou
 }
 
 void HipIntegrationUtilities::distributeForcesFromVirtualSites() {
+    ContextSelector selector(context);
     if (numVsites > 0) {
         vsiteForceKernel->setArg(2, context.getLongForceBuffer());
         vsiteForceKernel->execute(numVsites);

platforms/hip/src/HipNonbondedUtilities.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2009-2018 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2009-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -439,6 +439,10 @@ void HipNonbondedUtilities::computeInteractions(int forceGroups, bool includeFor
 bool HipNonbondedUtilities::updateNeighborListSize() {
     if (!useCutoff)
         return false;
+    if (context.getStepsSinceReorder() == 0)
+        tilesAfterReorder = pinnedCountBuffer[0];
+    else if (context.getStepsSinceReorder() > 25 && pinnedCountBuffer[0] > 1.1*tilesAfterReorder)
+        context.forceReorder();
     if (pinnedCountBuffer[0] <= maxTiles && pinnedCountBuffer[1] <= maxSinglePairs)
         return false;
 
@@ -446,12 +450,13 @@ bool HipNonbondedUtilities::updateNeighborListSize() {
     // this from happening in the future.
 
     if (pinnedCountBuffer[0] > maxTiles) {
-        maxTiles = (int) (1.2*pinnedCountBuffer[0]);
-        int totalTiles = context.getNumAtomBlocks()*(context.getNumAtomBlocks()+1)/2;
+        maxTiles = (unsigned int) (1.2*pinnedCountBuffer[0]);
+        unsigned int numBlocks = context.getNumAtomBlocks();
+        int totalTiles = numBlocks*(numBlocks+1)/2;
         if (maxTiles > totalTiles)
             maxTiles = totalTiles;
         interactingTiles.resize(maxTiles);
-        interactingAtoms.resize(HipContext::TileSize*maxTiles);
+        interactingAtoms.resize(HipContext::TileSize*(size_t) maxTiles);
         if (forceArgs.size() > 0)
             forceArgs[7] = &interactingTiles.getDevicePointer();
         findInteractingBlocksArgs[6] = &interactingTiles.getDevicePointer();

platforms/hip/src/HipParallelKernels.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2011-2019 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2011-2021 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2021 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -27,6 +27,7 @@
 
 #include "HipParallelKernels.h"
 #include "HipKernelSources.h"
+#include "openmm/common/ContextSelector.h"
 
 using namespace OpenMM;
 using namespace std;
@@ -70,7 +71,7 @@ public:
     void execute() {
         // Copy coordinates over to this device and execute the kernel.
 
-        cu.setAsCurrent();
+        ContextSelector selector(cu);
         if (cu.getContextIndex() > 0) {
             hipStreamWaitEvent(cu.getCurrentStream(), event, 0);
             if (!cu.getPlatformData().peerAccessSupported)
@@ -94,13 +95,16 @@ private:
 class HipParallelCalcForcesAndEnergyKernel::FinishComputationTask : public HipContext::WorkTask {
 public:
     FinishComputationTask(ContextImpl& context, HipContext& cu, HipCalcForcesAndEnergyKernel& kernel,
-            bool includeForce, bool includeEnergy, int groups, double& energy, long long& completionTime, long long* pinnedMemory, HipArray& contextForces, bool& valid, int2& interactionCount) :
+            bool includeForce, bool includeEnergy, int groups, double& energy, long long& completionTime, long long* pinnedMemory, HipArray& contextForces,
+            bool& valid, int2& interactionCount, hipStream_t stream, hipEvent_t event, hipEvent_t localEvent) :
             context(context), cu(cu), kernel(kernel), includeForce(includeForce), includeEnergy(includeEnergy), groups(groups), energy(energy),
-            completionTime(completionTime), pinnedMemory(pinnedMemory), contextForces(contextForces), valid(valid), interactionCount(interactionCount) {
+            completionTime(completionTime), pinnedMemory(pinnedMemory), contextForces(contextForces), valid(valid), interactionCount(interactionCount),
+            stream(stream), event(event), localEvent(localEvent) {
     }
     void execute() {
         // Execute the kernel, then download forces.
 
+        ContextSelector selector(cu);
         energy += kernel.finishComputation(context, includeForce, includeEnergy, groups, valid);
         if (cu.getComputeForceCount() < 200) {
             // Record timing information for load balancing.  Since this takes time, only do it at the start of the simulation.
@@ -110,13 +114,16 @@ public:
         }
         if (includeForce) {
             if (cu.getContextIndex() > 0) {
+                hipEventRecord(localEvent, cu.getCurrentStream());
+                hipStreamWaitEvent(stream, localEvent, 0);
                 int numAtoms = cu.getPaddedNumAtoms();
                 if (cu.getPlatformData().peerAccessSupported) {
                     int numBytes = numAtoms*3*sizeof(long long);
                     int offset = (cu.getContextIndex()-1)*numBytes;
                     HipContext& context0 = *cu.getPlatformData().contexts[0];
-                    CHECK_RESULT(hipMemcpy(static_cast<char*>(contextForces.getDevicePointer())+offset,
-                                           cu.getForce().getDevicePointer(), numBytes, hipMemcpyDeviceToDevice), "Error copying forces");
+                    CHECK_RESULT(hipMemcpyAsync(static_cast<char*>(contextForces.getDevicePointer())+offset,
+                                           cu.getForce().getDevicePointer(), numBytes, hipMemcpyDeviceToDevice, stream), "Error copying forces");
+                    hipEventRecord(event, stream);
                 }
                 else
                     cu.getForce().download(&pinnedMemory[(cu.getContextIndex()-1)*numAtoms*3]);
@@ -140,6 +147,9 @@ private:
     HipArray& contextForces;
     bool& valid;
     int2& interactionCount;
+    hipStream_t stream;
+    hipEvent_t event;
+    hipEvent_t localEvent;
 };
 
 HipParallelCalcForcesAndEnergyKernel::HipParallelCalcForcesAndEnergyKernel(string name, const Platform& platform, HipPlatform::PlatformData& data) :
@@ -150,20 +160,25 @@ HipParallelCalcForcesAndEnergyKernel::HipParallelCalcForcesAndEnergyKernel(strin
 }
 
 HipParallelCalcForcesAndEnergyKernel::~HipParallelCalcForcesAndEnergyKernel() {
-    data.contexts[0]->setAsCurrent();
+    ContextSelector selector(*data.contexts[0]);
     if (pinnedPositionBuffer != NULL)
         hipHostFree(pinnedPositionBuffer);
     if (pinnedForceBuffer != NULL)
         hipHostFree(pinnedForceBuffer);
     hipEventDestroy(event);
-    hipStreamDestroy(peerCopyStream);
+    for (int i = 0; i < peerCopyEvent.size(); i++)
+        hipEventDestroy(peerCopyEvent[i]);
+    for (int i = 0; i < peerCopyEventLocal.size(); i++)
+        hipEventDestroy(peerCopyEventLocal[i]);
+    for (int i = 0; i < peerCopyStream.size(); i++)
+        hipStreamDestroy(peerCopyStream[i]);
     if (interactionCounts != NULL)
         hipHostFree(interactionCounts);
 }
 
 void HipParallelCalcForcesAndEnergyKernel::initialize(const System& system) {
     HipContext& cu = *data.contexts[0];
-    cu.setAsCurrent();
+    ContextSelector selector(cu);
     hipModule_t module = cu.createModule(HipKernelSources::parallel);
     sumKernel = cu.getKernel(module, "sumForces");
     int numContexts = data.contexts.size();
@@ -171,14 +186,25 @@ void HipParallelCalcForcesAndEnergyKernel::initialize(const System& system) {
         getKernel(i).initialize(system);
     for (int i = 0; i < numContexts; i++)
         contextNonbondedFractions[i] = 1/(double) numContexts;
-    CHECK_RESULT(hipEventCreateWithFlags(&event, 0), "Error creating event");
-    CHECK_RESULT(hipStreamCreateWithFlags(&peerCopyStream, hipStreamNonBlocking), "Error creating stream");
+    CHECK_RESULT(hipEventCreateWithFlags(&event, cu.getEventFlags()), "Error creating event");
+    peerCopyEvent.resize(numContexts);
+    peerCopyEventLocal.resize(numContexts);
+    peerCopyStream.resize(numContexts);
+    for (int i = 0; i < numContexts; i++) {
+        CHECK_RESULT(hipEventCreateWithFlags(&peerCopyEvent[i], cu.getEventFlags()), "Error creating event");
+        CHECK_RESULT(hipStreamCreateWithFlags(&peerCopyStream[i], hipStreamNonBlocking), "Error creating stream");
+    }
+    for (int i = 0; i < numContexts; i++) {
+        HipContext& cuLocal = *data.contexts[i];
+        ContextSelector selectorLocal(cuLocal);
+        CHECK_RESULT(hipEventCreateWithFlags(&peerCopyEventLocal[i], cu.getEventFlags()), "Error creating event");
+    }
     CHECK_RESULT(hipHostMalloc((void**) &interactionCounts, numContexts*sizeof(int2), 0), "Error creating interaction counts buffer");
 }
 
 void HipParallelCalcForcesAndEnergyKernel::beginComputation(ContextImpl& context, bool includeForce, bool includeEnergy, int groups) {
     HipContext& cu = *data.contexts[0];
-    cu.setAsCurrent();
+    ContextSelector selector(cu);
     if (!contextForces.isInitialized()) {
         contextForces.initialize<long long>(cu, 3*(data.contexts.size()-1)*cu.getPaddedNumAtoms(), "contextForces");
         CHECK_RESULT(hipHostMalloc((void**) &pinnedForceBuffer, 3*(data.contexts.size()-1)*cu.getPaddedNumAtoms()*sizeof(long long), hipHostMallocPortable), "Error allocating pinned memory");
@@ -194,36 +220,44 @@ void HipParallelCalcForcesAndEnergyKernel::beginComputation(ContextImpl& context
     else {
         int numBytes = cu.getPosq().getSize()*cu.getPosq().getElementSize();
         hipEventRecord(event, cu.getCurrentStream());
-        hipStreamWaitEvent(peerCopyStream, event, 0);
-        for (int i = 1; i < (int) data.contexts.size(); i++)
+        for (int i = 1; i < (int) data.contexts.size(); i++) {
+            hipStreamWaitEvent(peerCopyStream[i], event, 0);
             CHECK_RESULT(hipMemcpyAsync(
                 data.contexts[i]->getPosq().getDevicePointer(),
                 cu.getPosq().getDevicePointer(), numBytes,
-                hipMemcpyDeviceToDevice, peerCopyStream), "Error copying positions");
-        hipEventRecord(event, peerCopyStream);
+                hipMemcpyDeviceToDevice, peerCopyStream[i]), "Error copying positions");
+            hipEventRecord(peerCopyEvent[i], peerCopyStream[i]);
+        }
     }
     for (int i = 0; i < (int) data.contexts.size(); i++) {
         data.contextEnergy[i] = 0.0;
         HipContext& cu = *data.contexts[i];
         ComputeContext::WorkThread& thread = cu.getWorkThread();
-        thread.addTask(new BeginComputationTask(context, cu, getKernel(i), includeForce, includeEnergy, groups, pinnedPositionBuffer, event, interactionCounts[i]));
+        hipEvent_t waitEvent = (cu.getPlatformData().peerAccessSupported ? peerCopyEvent[i] : event);
+        thread.addTask(new BeginComputationTask(context, cu, getKernel(i), includeForce, includeEnergy, groups, pinnedPositionBuffer, waitEvent, interactionCounts[i]));
     }
+    data.syncContexts();
 }
 
 double HipParallelCalcForcesAndEnergyKernel::finishComputation(ContextImpl& context, bool includeForce, bool includeEnergy, int groups, bool& valid) {
     for (int i = 0; i < (int) data.contexts.size(); i++) {
         HipContext& cu = *data.contexts[i];
         ComputeContext::WorkThread& thread = cu.getWorkThread();
-        thread.addTask(new FinishComputationTask(context, cu, getKernel(i), includeForce, includeEnergy, groups, data.contextEnergy[i], completionTimes[i], pinnedForceBuffer, contextForces, valid, interactionCounts[i]));
+        thread.addTask(new FinishComputationTask(context, cu, getKernel(i), includeForce, includeEnergy, groups, data.contextEnergy[i], completionTimes[i],
+                pinnedForceBuffer, contextForces, valid, interactionCounts[i], peerCopyStream[i], peerCopyEvent[i], peerCopyEventLocal[i]));
     }
     data.syncContexts();
+    HipContext& cu = *data.contexts[0];
+    ContextSelector selector(cu);
+    if (cu.getPlatformData().peerAccessSupported)
+        for (int i = 1; i < data.contexts.size(); i++)
+            hipStreamWaitEvent(cu.getCurrentStream(), peerCopyEvent[i], 0);
     double energy = 0.0;
     for (int i = 0; i < (int) data.contextEnergy.size(); i++)
         energy += data.contextEnergy[i];
     if (includeForce && valid) {
         // Sum the forces from all devices.
 
-        HipContext& cu = *data.contexts[0];
         if (!cu.getPlatformData().peerAccessSupported)
             contextForces.upload(pinnedForceBuffer, false);
         int bufferSize = 3*cu.getPaddedNumAtoms();

platforms/hip/src/kernels/utilities.hip

@@ -80,7 +80,7 @@ __global__ void reduceEnergy(const mixed* __restrict__ energyBuffer, mixed* __re
     extern __shared__ mixed tempBuffer[];
     const unsigned int thread = threadIdx.x;
     mixed sum = 0;
-    for (unsigned int index = thread; index < bufferSize; index += blockDim.x)
+    for (unsigned int index = blockDim.x*blockIdx.x+threadIdx.x; index < bufferSize; index += blockDim.x*gridDim.x)
         sum += energyBuffer[index];
     tempBuffer[thread] = sum;
     for (int i = 1; i < workGroupSize; i *= 2) {
@@ -89,7 +89,7 @@ __global__ void reduceEnergy(const mixed* __restrict__ energyBuffer, mixed* __re
             tempBuffer[thread] += tempBuffer[thread+i];
     }
     if (thread == 0)
-        *result = tempBuffer[0];
+        result[blockIdx.x] = tempBuffer[0];
 }
 
 /**

platforms/hip/tests/HipTests.h

@@ -41,4 +41,6 @@ OpenMM::HipPlatform platform;
 void initializeTests(int argc, char* argv[]) {
     if (argc > 1)
         platform.setPropertyDefaultValue("Precision", std::string(argv[1]));
+    if (argc > 2)
+        platform.setPropertyDefaultValue("DeviceIndex", std::string(argv[2]));
 }

platforms/hip/tests/TestHipFFT3D.cpp

@@ -6,8 +6,8 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2011-2016 Stanford University and the Authors.      *
- * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
+ * Portions copyright (c) 2011-2022 Stanford University and the Authors.      *
+ * Portions copyright (c) 2020-2022 Advanced Micro Devices, Inc.              *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
  *                                                                            *
@@ -38,12 +38,16 @@
 #include "HipArray.h"
 #include "HipContext.h"
 #include "HipFFT3D.h"
-#include "fftpack.h"
 #include "sfmt/SFMT.h"
 #include "openmm/System.h"
+#include <complex>
 #include <iostream>
 #include <cmath>
 #include <set>
+#ifdef _MSC_VER
+  #define POCKETFFT_NO_VECTORS
+#endif
+#include "pocketfft_hdronly.h"
 
 using namespace OpenMM;
 using namespace std;
@@ -67,19 +71,19 @@ void testTransform(bool realToComplex, int xsize, int ysize, int zsize, double e
     OpenMM_SFMT::SFMT sfmt;
     init_gen_rand(0, sfmt);
     vector<Real2> original(xsize*ysize*zsize);
-    vector<t_complex> reference(original.size());
+    vector<complex<double>> reference(original.size());
     for (int i = 0; i < (int) original.size(); i++) {
         Real2 value;
         value.x = (float) genrand_real2(sfmt);
         value.y = (float) genrand_real2(sfmt);
         original[i] = value;
-        reference[i] = t_complex(value.x, value.y);
+        reference[i] = complex<double>(value.x, value.y);
     }
     for (int i = 0; i < (int) reference.size(); i++) {
         if (realToComplex)
-            reference[i] = t_complex(i%2 == 0 ? original[i/2].x : original[i/2].y, 0);
+            reference[i] = complex<double>(i%2 == 0 ? original[i/2].x : original[i/2].y, 0);
         else
-            reference[i] = t_complex(original[i].x, original[i].y);
+            reference[i] = complex<double>(original[i].x, original[i].y);
     }
     HipArray grid1(context, original.size(), sizeof(Real2), "grid1");
     HipArray grid2(context, original.size(), sizeof(Real2), "grid2");
@@ -91,19 +95,21 @@ void testTransform(bool realToComplex, int xsize, int ysize, int zsize, double e
     fft.execFFT(true);
     vector<Real2> result;
     grid2.download(result);
-    fftpack_t plan;
-    fftpack_init_3d(&plan, xsize, ysize, zsize);
-    fftpack_exec_3d(plan, FFTPACK_FORWARD, &reference[0], &reference[0]);
+    vector<size_t> shape = {(size_t) xsize, (size_t) ysize, (size_t) zsize};
+    vector<size_t> axes = {0, 1, 2};
+    vector<ptrdiff_t> stride = {(ptrdiff_t) (ysize*zsize*sizeof(complex<double>)),
+                                (ptrdiff_t) (zsize*sizeof(complex<double>)),
+                                (ptrdiff_t) sizeof(complex<double>)};
+    pocketfft::c2c(shape, stride, stride, axes, true, reference.data(), reference.data(), 1.0);
     int outputZSize = (realToComplex ? zsize/2+1 : zsize);
     for (int x = 0; x < xsize; x++)
         for (int y = 0; y < ysize; y++)
             for (int z = 0; z < outputZSize; z++) {
                 int index1 = x*ysize*zsize + y*zsize + z;
                 int index2 = x*ysize*outputZSize + y*outputZSize + z;
-                ASSERT_EQUAL_TOL(reference[index1].re, result[index2].x, 1e-3 * eps);
-                ASSERT_EQUAL_TOL(reference[index1].im, result[index2].y, 1e-3 * eps);
+                ASSERT_EQUAL_TOL(reference[index1].real(), result[index2].x, 1e-3 * eps);
+                ASSERT_EQUAL_TOL(reference[index1].imag(), result[index2].y, 1e-3 * eps);
             }
-    fftpack_destroy(plan);
 
     // Perform a backward transform and see if we get the original values.
 

platforms/hip/tests/TestHipNonbondedForce.cpp

@@ -6,7 +6,7 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2008-2015 Stanford University and the Authors.      *
+ * Portions copyright (c) 2008-2021 Stanford University and the Authors.      *
  * Portions copyright (c) 2020 Advanced Micro Devices, Inc.                   *
  * Authors: Peter Eastman, Nicholas Curtis                                    *
  * Contributors:                                                              *
@@ -50,13 +50,19 @@ void testParallelComputation(NonbondedForce::NonbondedMethod method) {
     vector<Vec3> positions(numParticles);
     for (int i = 0; i < numParticles; i++)
         positions[i] = Vec3(5*genrand_real2(sfmt), 5*genrand_real2(sfmt), 5*genrand_real2(sfmt));
+    force->addGlobalParameter("scale", 0.5);
     for (int i = 0; i < numParticles; ++i)
         for (int j = 0; j < i; ++j) {
             Vec3 delta = positions[i]-positions[j];
-            if (delta.dot(delta) < 0.1)
+            if (delta.dot(delta) < 0.1) {
                 force->addException(i, j, 0, 1, 0);
+            }
+            else if (delta.dot(delta) < 0.2) {
+                int index = force->addException(i, j, 0.5, 1, 1.0);
+                force->addExceptionParameterOffset("scale", index, 0.5, 0.4, 0.3);
+            }
         }
-
+    
     // Create two contexts, one with a single device and one with two devices.
 
     VerletIntegrator integrator1(0.01);
@@ -179,6 +185,7 @@ void runPlatformTests() {
     testParallelComputation(NonbondedForce::NoCutoff);
     testParallelComputation(NonbondedForce::Ewald);
     testParallelComputation(NonbondedForce::PME);
+    testParallelComputation(NonbondedForce::LJPME);
     testReordering();
     testDeterministicForces();
     if (canRunHugeTest())

platforms/hip/tests/TestHipRandom.cpp

@@ -60,6 +60,7 @@ void testGaussian() {
             platform.getPropertyDefaultValue(HipPlatform::HipDisablePmeStream()), "false", 1, NULL);
     HipContext& context = *platformData.contexts[0];
     context.initialize();
+    context.setAsCurrent();
     context.getIntegrationUtilities().initRandomNumberGenerator(0);
     HipArray& random = context.getIntegrationUtilities().getRandom();
     context.getIntegrationUtilities().prepareRandomNumbers(random.getSize());

platforms/hip/tests/TestHipSort.cpp

@@ -70,6 +70,7 @@ void verifySorting(vector<float> array, bool uniform) {
             platform.getPropertyDefaultValue(HipPlatform::HipDisablePmeStream()), "false", 1, NULL);
     HipContext& context = *platformData.contexts[0];
     context.initialize();
+    context.setAsCurrent();
     HipArray data(context, array.size(), 4, "sortData");
     data.upload(array);
     HipSort sort(context, new SortTrait(), array.size(), uniform);

plugins/amoeba/platforms/hip/src/AmoebaHipKernels.cpp

@@ -6,7 +6,7 @@
  * Biological Structures at Stanford, funded under the NIH Roadmap for        *
  * Medical Research, grant U54 GM072970. See https://simtk.org.               *
  *                                                                            *
- * Portions copyright (c) 2008-2020 Stanford University and the Authors.      *
+ * Portions copyright (c) 2008-2021 Stanford University and the Authors.      *
  * Portions copyright (c) 2021 Advanced Micro Devices, Inc.                   *
  * Authors: Peter Eastman, Mark Friedrichs                                    *
  * Contributors:                                                              *
@@ -29,6 +29,7 @@
   #define _USE_MATH_DEFINES // Needed to get M_PI
 #endif
 #include "AmoebaHipKernels.h"
+#include "openmm/common/ContextSelector.h"
 #include "openmm/internal/ContextImpl.h"
 #include "openmm/internal/AmoebaGeneralizedKirkwoodForceImpl.h"
 #include "openmm/internal/AmoebaMultipoleForceImpl.h"
@@ -56,7 +57,7 @@ using namespace std;
  * -------------------------------------------------------------------------- */
 
 HipCalcAmoebaMultipoleForceKernel::~HipCalcAmoebaMultipoleForceKernel() {
-    cc.setAsCurrent();
+    ContextSelector selector(cc);
     if (fft != NULL)
         delete fft;
 }
@@ -64,6 +65,7 @@ HipCalcAmoebaMultipoleForceKernel::~HipCalcAmoebaMultipoleForceKernel() {
 void HipCalcAmoebaMultipoleForceKernel::initialize(const System& system, const AmoebaMultipoleForce& force) {
     CommonCalcAmoebaMultipoleForceKernel::initialize(system, force);
     if (usePME) {
+        ContextSelector selector(cc);
         HipArray& grid1 = cu.unwrap(pmeGrid1);
         HipArray& grid2 = cu.unwrap(pmeGrid2);
         fft = cu.createFFT(gridSizeX, gridSizeY, gridSizeZ, false, cu.getCurrentStream(), grid1, grid2);
@@ -79,7 +81,7 @@ void HipCalcAmoebaMultipoleForceKernel::computeFFT(bool forward) {
  * -------------------------------------------------------------------------- */
 
 HipCalcHippoNonbondedForceKernel::~HipCalcHippoNonbondedForceKernel() {
-    cc.setAsCurrent();
+    ContextSelector selector(cc);
     if (sort != NULL)
         delete sort;
     if (fft != NULL)
@@ -91,6 +93,7 @@ HipCalcHippoNonbondedForceKernel::~HipCalcHippoNonbondedForceKernel() {
 void HipCalcHippoNonbondedForceKernel::initialize(const System& system, const HippoNonbondedForce& force) {
     CommonCalcHippoNonbondedForceKernel::initialize(system, force);
     if (usePME) {
+        ContextSelector selector(cc);
         sort = new HipSort(cu, new SortTrait(), cc.getNumAtoms());
         HipArray& grid1 = cu.unwrap(pmeGrid1);
         HipArray& grid2 = cu.unwrap(pmeGrid2);