Changed order of arguments to spherical_harm (#969)

* Changed order of arguments to spherical_harm

Since scipy 1.15 the sph_harm has been deprecated
in favor of sph_harm_y (with changed argument order).

Now sisl obeys the same order of arguments.

* added change-logs

Author: zerothi

changes/968.fix.rst

@@ -0,0 +1 @@
+Fixed import error for scipy deprecations

changes/969.change.rst

@@ -0,0 +1,4 @@
+Changed spherical_harm argument order to match scipy 1.17
+
+Since this is generally not really used, it should
+be safe to do. Sorry for the inconvenience.

src/sisl/_core/orbital.py

@@ -65,7 +65,7 @@ def _rfact(l, m):
 del _rfact
 
 
-def _rspherical_harm(m, l, theta, cos_phi):
+def _rspherical_harm(l, m, theta, cos_phi):
     r""" Calculates the real spherical harmonics using :math:`Y_l^m(\theta, \varphi)` with :math:`\mathbf r\to \{r, \theta, \varphi\}`.
 
     These real spherical harmonics are via these equations:
@@ -79,10 +79,10 @@ def _rspherical_harm(m, l, theta, cos_phi):
 
     Parameters
     ----------
-    m : int
-       order of the spherical harmonics
     l : int
        degree of the spherical harmonics
+    m : int
+       order of the spherical harmonics
     theta : array_like
        angle in :math:`xy` plane (azimuthal)
     cos_phi : array_like
@@ -697,8 +697,8 @@ def spher(self, theta, phi, m: int = 0, cos_phi: bool = False):
            spherical harmonics at angles :math:`\theta` and :math:`\phi` and given quantum number `m`
         """
         if cos_phi:
-            return _rspherical_harm(m, self.l, theta, phi)
-        return _rspherical_harm(m, self.l, theta, cos(phi))
+            return _rspherical_harm(self.l, m, theta, phi)
+        return _rspherical_harm(self.l, m, theta, cos(phi))
 
     def psi(self, r, m: int = 0):
         r"""Calculate :math:`\phi(\mathbf r)` at a given point (or more points)
@@ -1610,8 +1610,8 @@ def spher(self, theta, phi, cos_phi: bool = False):
             spherical harmonics at angles :math:`\theta` and :math:`\phi`
         """
         if cos_phi:
-            return _rspherical_harm(self.m, self.l, theta, phi)
-        return _rspherical_harm(self.m, self.l, theta, cos(phi))
+            return _rspherical_harm(self.l, self.m, theta, phi)
+        return _rspherical_harm(self.l, self.m, theta, cos(phi))
 
     def psi_spher(self, r, theta, phi, cos_phi: bool = False):
         r"""Calculate :math:`\phi(|\mathbf r|, \theta, \phi)` at a given point (in spherical coordinates)

src/sisl/utils/mathematics.py

@@ -25,7 +25,23 @@
     take,
     zeros_like,
 )
-from scipy.special import sph_harm
+
+try:
+    # from 1.15 and onwards
+    from scipy.special import sph_harm_y
+
+    def _sph_harm(n, m, theta, phi, diff_n: int = 0):
+        return sph_harm_y(n, m, theta, phi, diff_n=diff_n)
+
+except ImportError:
+    # deprecated since 1.15
+    # note the order has changed of the arguments
+    from scipy.special import sph_harm
+
+    def _sph_harm(n, m, theta, phi, diff_n: int = 0):
+        assert diff_n == 0
+        return sph_harm(m, n, theta, phi)
+
 
 from sisl import _array as _a
 from sisl._core.quaternion import Quaternion
@@ -219,7 +235,7 @@ def cart2spher(r, theta: bool = True, cos_phi: bool = False, maxR=None):
     return idx, rr, theta, phi
 
 
-def spherical_harm(m, l, theta, phi):
+def spherical_harm(l, m, theta, phi, diff_n: int = 0):
     r"""Calculate the spherical harmonics using :math:`Y_l^m(\theta, \varphi)` with :math:`\mathbf r\to \{r, \theta, \varphi\}`.
 
     .. math::
@@ -230,19 +246,21 @@ def spherical_harm(m, l, theta, phi):
 
     Parameters
     ----------
-    m : int
-       order of the spherical harmonics
     l : int
        degree of the spherical harmonics
+    m : int
+       order of the spherical harmonics
     theta : array_like
        angle in :math:`xy` plane (azimuthal)
     phi : array_like
        angle from :math:`z` axis (polar)
+    diff_n : int
+        if a recent enough scipy (>=1.16), one can calculate the derivatives.
     """
     # Probably same as:
     # return (-1) ** m * ( (2*l+1)/(4*pi) * factorial(l-m) / factorial(l+m) ) ** 0.5 \
     #    * lpmv(m, l, cos(theta)) * exp(1j * m * phi)
-    return sph_harm(m, l, theta, phi) * (-1) ** m
+    return _sph_harm(l, m, theta, phi, diff_n=diff_n) * (-1) ** m
 
 
 def curl(M, axis=-2, axisv=-1):