diff --git a/binarycpython/utils/distribution_functions.py b/binarycpython/utils/distribution_functions.py
index b9476e04567144dcce331cf4c1976ea450d667b2..be040aa73fed43a9bc895701657917d679307485 100644
--- a/binarycpython/utils/distribution_functions.py
+++ b/binarycpython/utils/distribution_functions.py
@@ -118,7 +118,7 @@ def const(
             print("out of bounds")
             prob = 0
             return prob
-    prob = 1.0 / (min_bound - max_bound)
+    prob = 1.0 / (max_bound - min_bound)
     return prob
 
 
@@ -501,12 +501,12 @@ def ktg93(m: Union[int, float], newopts: dict = None) -> Union[int, float]:
     return three_part_powerlaw(
         m,
         value_dict["m0"],
-        value_dict["m0"],
+        value_dict["m1"],
         value_dict["m2"],
-        value_dict["m0"],
-        value_dict["m0"],
-        value_dict["m0"],
-        value_dict["m0"],
+        value_dict["mmax"],
+        value_dict["p1"],
+        value_dict["p2"],
+        value_dict["p3"],
     )
 
 
@@ -577,7 +577,7 @@ def imf_chabrier2003(m: Union[int, float]) -> Union[int, float]:
     chabrier_a1 = 0.158
     chabrier_a2 = 4.43e-2
     chabrier_x = -1.3
-    if m < 0:
+    if m <= 0:
         print("below bounds")
         raise ValueError
     if 0 < m < 1.0: