Changeset d86f0fc in sasmodels for sasmodels/guyou.py

Timestamp:

Mar 26, 2018 3:52:24 PM (6 years ago)

Author:

Paul Kienzle <pkienzle@…>

Branches:

master, core_shell_microgels, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests

Children:

802c412

Parents:

f4ae8c4

Message:

lint reduction

File:

• sasmodels/guyou.py (modified) (11 diffs)

sasmodels/guyou.py

@@ -31 +31 @@
 #
 # 2017-11-01 Paul Kienzle
-# * converted to python, using degrees rather than radians
+# * converted to python, with degrees rather than radians
+"""
+Convert between latitude-longitude and Guyou map coordinates.
+"""
+
 from __future__ import division, print_function
 
 import numpy as np
-from numpy import sqrt, pi, tan, cos, sin, log, exp, arctan2 as atan2, sign, radians, degrees
+from numpy import sqrt, pi, tan, cos, sin, sign, radians, degrees
+from numpy import sinh, arctan as atan
+
+# scipy version of special functions
+from scipy.special import ellipj as ellipticJ, ellipkinc as ellipticF
 
 _ = """
@@ -59 +67 @@
 """
 
-# scipy version of special functions
-from scipy.special import ellipj as ellipticJ, ellipkinc as ellipticF
-from numpy import sinh, sign, arctan as atan
-
 def ellipticJi(u, v, m):
     scalar = np.isscalar(u) and np.isscalar(v) and np.isscalar(m)
     u, v, m = np.broadcast_arrays(u, v, m)
-    result = np.empty_like([u,u,u], 'D')
-    real = v==0
-    imag = u==0
+    result = np.empty_like([u, u, u], 'D')
+    real = (v == 0)
+    imag = (u == 0)
     mixed = ~(real|imag)
     result[:, real] = _ellipticJi_real(u[real], m[real])
     result[:, imag] = _ellipticJi_imag(v[imag], m[imag])
     result[:, mixed] = _ellipticJi(u[mixed], v[mixed], m[mixed])
-    return result[0,:] if scalar else result
+    return result[0, :] if scalar else result
 
 def _ellipticJi_real(u, m):
@@ -104 +108 @@
         result = np.empty_like(phi, 'D')
         index = (phi == 0)
-        result[index] = ellipticF(atan(sinh(abs(phi[index]))), 1-m[index]) * sign(psi[index])
+        result[index] = ellipticF(atan(sinh(abs(phi[index]))),
+                                  1-m[index]) * sign(psi[index])
         result[~index] = ellipticFi(phi[~index], psi[~index], m[~index])
         return result.reshape(1)[0] if scalar else result
@@ -117 +122 @@
     cotlambda2 = (-b + sqrt(b * b - 4 * c)) / 2
     re = ellipticF(atan(1 / sqrt(cotlambda2)), m) * sign(phi)
-    im = ellipticF(atan(sqrt(np.maximum(0,(cotlambda2 / cotphi2 - 1) / m))), 1 - m) * sign(psi)
+    im = ellipticF(atan(sqrt(np.maximum(0, (cotlambda2 / cotphi2 - 1) / m))),
+                   1 - m) * sign(psi)
     return re + 1j*im
 
-sqrt2 = sqrt(2)
+SQRT2 = sqrt(2)
 
 # [PAK] renamed k_ => cos_u, k => sin_u, k*k => sinsq_u to avoid k,K confusion
@@ -127 +133 @@
 # K = 3.165103454447431823666270142140819753058976299237578486994...
 def guyou(lam, phi):
+    """Transform from (latitude, longitude) to point (x, y)"""
     # [PAK] wrap into [-pi/2, pi/2] radians
     x, y = np.asarray(lam), np.asarray(phi)
@@ -135 +142 @@
 
     # Compute constant K
-    cos_u = (sqrt2 - 1) / (sqrt2 + 1)
+    cos_u = (SQRT2 - 1) / (SQRT2 + 1)
     sinsq_u = 1 - cos_u**2
     K = ellipticF(pi/2, sinsq_u)
@@ -144 +151 @@
     at = atan(r * (cos(lam) - 1j*sin(lam)))
     t = ellipticFi(at.real, at.imag, sinsq_u)
-    x, y = (-t.imag, sign(phi + (phi==0))*(0.5 * K - t.real))
+    x, y = (-t.imag, sign(phi + (phi == 0))*(0.5 * K - t.real))
 
     # [PAK] convert to degrees, and return to original tile
@@ -150 +157 @@
 
 def guyou_invert(x, y):
+    """Transform from point (x, y) on plot to (latitude, longitude)"""
     # [PAK] wrap into [-pi/2, pi/2] radians
     x, y = np.asarray(x), np.asarray(y)
@@ -158 +166 @@
 
     # compute constant K
-    cos_u = (sqrt2 - 1) / (sqrt2 + 1)
+    cos_u = (SQRT2 - 1) / (SQRT2 + 1)
     sinsq_u = 1 - cos_u**2
     K = ellipticF(pi/2, sinsq_u)
@@ -174 +182 @@
 
 def plot_grid():
+    """Plot the latitude-longitude grid for Guyou transform"""
     import matplotlib.pyplot as plt
     from numpy import linspace
@@ -203 +212 @@
     plt.ylabel('latitude')
 
+def main():
+    plot_grid()
+    import matplotlib.pyplot as plt
+    plt.show()
+
 if __name__ == "__main__":
-    plot_grid()
-    import matplotlib.pyplot as plt; plt.show()
-
+    main()
 
 _ = """