accidentally broke multigpu a while ago :-/

examples/detector.c

@@ -23,6 +23,7 @@ void train_detector(char *datacfg, char *cfgfile, char *weightfile, int *gpus, i
         cuda_set_device(gpus[i]);
 #endif
         nets[i] = load_network(cfgfile, weightfile, clear);
+        nets[i].learning_rate *= ngpus;
     }
     srand(time(0));
     network net = nets[0];