Fixed -g argument so more than two GPUs can be provided

src/GPUManager.h

@@ -83,6 +83,7 @@ private:
 	static void init_comms();
 
 public:	
+	static size_t allGpuSize() { return allGpus.size(); }
 	static ncclComm_t* comms;
 	static std::vector<GPU> gpus;
 	

src/arbd.cpp

@@ -59,7 +59,7 @@ int main(int argc, char* argv[]) {
 	printf("  –––––––––––––––––––––––––––––––––––––––––––––\n");
 	GPUManager::init();
 
-	size_t n_gpus = max(GPUManager::gpus.size(), 1lu);
+	size_t n_gpus = GPUManager::allGpuSize();
 	std::vector<unsigned int> gpuIDs;
 	
 	bool debug = false, safe = false;