Fixed a problem under Nvidia's OpenCL implementation

platforms/opencl/src/OpenCLContext.cpp

@@ -39,6 +39,7 @@ using namespace OpenMM;
 using namespace std;
 
 OpenCLContext::OpenCLContext(int numParticles, int deviceIndex) : time(0.0), stepCount(0) {
+    try {
         context = cl::Context(CL_DEVICE_TYPE_ALL);
         vector<cl::Device> devices = context.getInfo<CL_CONTEXT_DEVICES>();
         const int minThreadBlockSize = 32;
@@ -59,7 +60,8 @@ OpenCLContext::OpenCLContext(int numParticles, int deviceIndex) : time(0.0), ste
         if (device.getInfo<CL_DEVICE_MAX_WORK_ITEM_SIZES>()[0] < minThreadBlockSize)
             throw OpenMMException("The specified OpenCL device is not compatible with OpenMM");
         compilationOptions = "-cl-fast-relaxed-math";
-    if (device.getInfo<CL_DEVICE_VENDOR>() == "NVIDIA")
+        string vendor = device.getInfo<CL_DEVICE_VENDOR>();
+        if (vendor.size() >= 6 && vendor.substr(0, 6) == "NVIDIA")
             compilationOptions += " -DWARPS_ARE_ATOMIC";
         queue = cl::CommandQueue(context, device);
         numAtoms = numParticles;
@@ -69,6 +71,12 @@ OpenCLContext::OpenCLContext(int numParticles, int deviceIndex) : time(0.0), ste
         nonbonded = new OpenCLNonbondedUtilities(*this);
         posq = new OpenCLArray<mm_float4>(*this, paddedNumAtoms, "posq", true);
         velm = new OpenCLArray<mm_float4>(*this, paddedNumAtoms, "velm", true);
+    }
+    catch (cl::Error err) {
+        std::stringstream str;
+        str<<"Error initializing context: "<<err.what()<<" ("<<err.err()<<")";
+        throw OpenMMException(str.str());
+    }
 
     // Create utility kernels that are used in multiple places.