Remove support for complex jnp.floor_divide

It is not well-defined, and the implementation is currently untested. Both Python and NumPy raise an error when attempting complex-valued floor division.

PiperOrigin-RevId: 621918604

Author: Jake VanderPlas

jax/_src/numpy/ufuncs.py

@@ -289,16 +289,7 @@ def floor_divide(x1: ArrayLike, x2: ArrayLike, /) -> Array:
     # TODO(mattjj): investigate why subtracting a scalar was causing promotion
     return _where(select, quotient - 1, quotient)
   elif dtypes.issubdtype(dtype, np.complexfloating):
-    x1r = lax.real(x1)
-    x1i = lax.imag(x1)
-    x2r = lax.real(x2)
-    x2i = lax.imag(x2)
-    which = lax.ge(lax.abs(x2r), lax.abs(x2i))
-    rat1 = _where(which, lax.full_like(x2i, 1), lax.div(x2r, x2i))
-    rat2 = _where(which, lax.div(x2i, x2r), _lax_const(x2i, 1))
-    out = lax.floor(lax.div(lax.add(lax.mul(x1r, rat1), lax.mul(x1i, rat2)),
-                            lax.add(lax.mul(x2r, rat1), lax.mul(x2i, rat2))))
-    return lax.convert_element_type(out, dtype)
+    raise TypeError("floor_divide does not support complex-valued inputs")
   else:
     return _float_divmod(x1, x2)[0]