make sure n and m are integer-valued

mtflearn/features/_zmoments.py

@@ -1,5 +1,7 @@
 import numpy as np
 
+import numpy as np
+
 def nm2j(n, m):
     """
     Convert Zernike radial order `n` and azimuthal frequency `m` to a single index `j`.
@@ -36,12 +38,21 @@ def nm2j(n, m):
     >>> nm2j([0, 1, 1], [0, -1, 1])
     array([0, 1, 2])
     """
-    n = np.asarray(n, dtype=int)
-    m = np.asarray(m, dtype=int)
+    n = np.asarray(n)
+    m = np.asarray(m)
 
     if n.shape != m.shape:
         raise ValueError("`n` and `m` must have the same shape.")
 
+    # Validate that n and m are integer-valued
+    if not np.all(np.isclose(n % 1, 0)):
+        raise ValueError("Radial order `n` must be integer-valued.")
+    if not np.all(np.isclose(m % 1, 0)):
+        raise ValueError("Azimuthal frequency `m` must be integer-valued.")
+
+    n = n.astype(int)
+    m = m.astype(int)
+
     # Validate inputs
     if np.any(n < 0):
         raise ValueError("Radial order `n` must be non-negative.")
@@ -59,7 +70,6 @@ def nm2j(n, m):
     else:
         return j
 
-
 def nm2j_complex(n, m):
     n = np.atleast_1d(n)
     m = np.atleast_1d(m)

mtflearn/features/test_zmoments.py

@@ -7,9 +7,9 @@ def test_scalar_inputs():
     assert nm2j(0, 0) == 0
     assert nm2j(1, -1) == 1
     assert nm2j(2, 0) == 4
-    assert nm2j(3, 1) == 7
-    assert nm2j(4, -4) == 8
-    assert nm2j(5, 3) == 13
+    assert nm2j(3, 1) == 8
+    assert nm2j(4, -4) == 10
+    assert nm2j(5, 3) == 19
 
 def test_array_inputs():
     """Test function with valid array inputs."""