[Rotation Synthesis] Replace np.float128 with np.longdouble (#1753)

np.float128 isn't supported on some platforms (such as mine). I think
np.longdouble is the recommended alternative? Let me know if you think
this would cause other problems.

Author: amandashoe

qualtran/rotation_synthesis/lattice/geometry.py

@@ -45,7 +45,7 @@ def from_bounds(start, end) -> "Range":
         elif all(rst.is_int(x) for x in sides):
             dtype = int
         elif any(isinstance(x, np.number) for x in sides):
-            dtype = np.float128
+            dtype = np.longdouble
         else:
             dtype = float
         return Range(*map(dtype, sides))

qualtran/rotation_synthesis/math_config.py

@@ -96,7 +96,7 @@ def arccos(self, x: Real) -> Real:
     np.arctan2,
     np.arcsin,
     np.arccos,
-    np.float128,
+    np.longdouble,
 )