fixing GPUWorkload<100 for minimal use cases, such as Tutorial

bioem_cuda.cu

@@ -618,7 +618,7 @@ int bioem_cuda::deviceStartRun()
 	}
 	else
 	{
-		maxRef = (size_t) RefMap.ntotRefMap * (size_t) GPUWorkload / 100;
+		maxRef = RefMap.ntotRefMap == 1 ? (size_t) RefMap.ntotRefMap : (size_t) RefMap.ntotRefMap * (size_t) GPUWorkload / 100;
 		pProb_host = new bioem_Probability;
 		pProb_host->init(maxRef, param.nTotGridAngles, param.nTotCC, *this);
 		pProb_host->copyFrom(&pProb, *this);