diff --git a/lib/src/aln_param.c b/lib/src/aln_param.c
index af447b6..5a7183d 100644
--- a/lib/src/aln_param.c
+++ b/lib/src/aln_param.c
@@ -82,7 +82,7 @@ int aln_param_init(struct aln_param **aln_param,int biotype , int n_threads, int
                 ap->gpe = gpe;
         }
 
-        if(gpe >= 0.0){
+        if(tgpe >= 0.0){
                 ap->tgpe = tgpe;
         }
         /* LOG_MSG("%f %f %f", ap->gpo, ap->gpe, ap->tgpe); */
diff --git a/python-kalign/__init__.py b/python-kalign/__init__.py
index 56f5686..a46596f 100644
--- a/python-kalign/__init__.py
+++ b/python-kalign/__init__.py
@@ -200,25 +200,23 @@ def align(
         gap_open = -1.0
     elif not isinstance(gap_open, (int, float)):
         raise ValueError("gap_open must be a number")
-    elif gap_open > 0:
-        raise ValueError("gap_open must be negative or zero (penalty values)")
+    elif gap_open < 0:
+        raise ValueError("gap_open must be positive or zero")
 
     if gap_extend is None:
         gap_extend = -1.0
     elif not isinstance(gap_extend, (int, float)):
         raise ValueError("gap_extend must be a number")
-    elif gap_extend > 0:
-        raise ValueError("gap_extend must be negative or zero (penalty values)")
+    elif gap_extend < 0:
+        raise ValueError("gap_extend must be positive or zero")
 
     if terminal_gap_extend is None:
         terminal_gap_extend = -1.0
     elif not isinstance(terminal_gap_extend, (int, float)):
         raise ValueError("terminal_gap_extend must be a number")
-    elif terminal_gap_extend > 0:
-        raise ValueError(
-            "terminal_gap_extend must be negative or zero (penalty values)"
-        )
-
+    elif terminal_gap_extend < 0:
+        raise ValueError("terminal_gap_extend must be positive or zero")
+    
     # Handle thread count
     if n_threads is None:
         n_threads = get_num_threads()