Get the device number from the thread id, not the other way around.
diff --git a/main.c b/main.c
index 06b9ffb..b5e5cbd 100644
--- a/main.c
+++ b/main.c
@@ -1925,7 +1925,7 @@ static bool active_device(int thr_id)
if (thr_id < gpu_threads) {
if (thr_id > nDevs)
return false;
- if (!gpu_devices[thr_id])
+ if (!gpu_devices[dev_from_id(thr_id)])
return false;
} else if (thr_id > gpu_threads + num_processors)
return false;