diff --git a/DAN-msa/ErrorPredictorMSA.py b/DAN-msa/ErrorPredictorMSA.py
index fb816bf..efb48b7 100755
--- a/DAN-msa/ErrorPredictorMSA.py
+++ b/DAN-msa/ErrorPredictorMSA.py
@@ -46,9 +46,8 @@ def main():
                         help="# of cpus to use for featurization (Default: 1)")
     parser.add_argument("--gpu",
                         "-g", action="store",
-                        type=int,
-                        default=0,
-                        help="gpu device to use (default gpu0)")
+                        default=None,
+                        help="specific gpu id to use, e.g. 0 for gpu0 (Default: None)")
     parser.add_argument("--featurize",
                         "-f",
                         action="store_true",
@@ -114,7 +113,9 @@ def main():
     # Importing larger libraries #
     ##############################
     os.environ['TF_CPP_MIN_LOG_LEVEL'] = '3'
-    os.environ["CUDA_VISIBLE_DEVICES"] = str(args.gpu)
+    if args.gpu is not None:
+        assert type(args.gpu) == int, 'GPU id must be specified as int, e.g. 0'
+        os.environ["CUDA_VISIBLE_DEVICES"] = str(args.gpu)
     script_dir = os.path.dirname(__file__)
     sys.path.insert(0, script_dir)
     import pyErrorPred
diff --git a/run_pyrosetta_ver.sh b/run_pyrosetta_ver.sh
index 53a6787..0938246 100755
--- a/run_pyrosetta_ver.sh
+++ b/run_pyrosetta_ver.sh
@@ -15,6 +15,7 @@ unset __conda_setup
 SCRIPT=`realpath -s $0`
 export PIPEDIR=`dirname $SCRIPT`
 
+GPU_ID="" # which gpu to use (int), for example 0 for gpu0. if none provided, it will let CUDA decide
 CPU="8"  # number of CPUs to use
 MEM="64" # max memory (in GB)
 
@@ -22,6 +23,10 @@ MEM="64" # max memory (in GB)
 IN="$1"                # input.fasta
 WDIR=`realpath -s $2`  # working folder
 
+if [ ! -z "$GPU_ID" ]
+  then
+    export CUDA_VISIBLE_DEVICES=$GPU_ID
+fi
 
 LEN=`tail -n1 $IN | wc -m`