fixup wigner symmetries

Author: johannes-moegerle

src/ryd_numerov/angular/utils.py

@@ -51,12 +51,12 @@ def calc_wigner_3j(j1: float, j2: float, j3: float, m1: float, m2: float, m3: fl
 
     # odd permutation -> sort seccond smallest j to be j2
     if j3 < j2:
-        symmetry_factor *= (-1) ** (j1 + j2 + j3)
+        symmetry_factor *= minus_one_pow(j1 + j2 + j3)
         j1, j2, j3, m1, m2, m3 = j1, j3, j2, m1, m3, m2  # noqa: PLW0127
 
     # sign of m -> make m1 positive (or m2 if m1==0)
     if m1 <= 0 or (m1 == 0 and m2 < 0):
-        symmetry_factor *= (-1) ** (j1 + j2 + j3)
+        symmetry_factor *= minus_one_pow(j1 + j2 + j3)
         m1, m2, m3 = -m1, -m2, -m3
 
     # TODO Regge symmetries
@@ -118,10 +118,10 @@ def calc_wigner_9j(
 
     # odd permutations of rows and columns-> make j2 <= j3 and j4 <= j7
     if js[2] < js[1]:
-        symmetry_factor *= (-1) ** sum(js)
+        symmetry_factor *= minus_one_pow(sum(js))
         js = [js[0], js[2], js[1], js[3], js[5], js[4], js[6], js[8], js[7]]
     if js[6] < js[3]:
-        symmetry_factor *= (-1) ** sum(js)
+        symmetry_factor *= minus_one_pow(sum(js))
         js = [*js[0:3], *js[6:9], *js[3:6]]
 
     # reflection about diagonal -> make j2 <= j4