From 1a700514da014a55fe126b2a49cf736b1f2f7257 Mon Sep 17 00:00:00 2001
From: Artem Moiseev <korvinos@bk.ru>
Date: Mon, 5 Feb 2018 16:51:11 +0100
Subject: [PATCH] #30 pep8 of cmod5n code

---
 openwind/cmod5n.py | 188 ++++++++++++++++++++++-----------------------
 1 file changed, 93 insertions(+), 95 deletions(-)

diff --git a/openwind/cmod5n.py b/openwind/cmod5n.py
index 60b4ad9..42f3e5b 100644
--- a/openwind/cmod5n.py
+++ b/openwind/cmod5n.py
@@ -1,130 +1,128 @@
+from numpy import cos, exp, tanh
 import warnings
 # Ignore overflow errors for wind calculations over land
 warnings.simplefilter("ignore", RuntimeWarning) 
 
-def cmod5n_forward(v,phi,theta):
-    '''!     ---------
-    !     cmod5n_forward(v, phi, theta)
-    !         inputs:
-    !              v     in [m/s] wind velocity (always >= 0)
-    !              phi   in [deg] angle between azimuth and wind direction
-    !                    (= D - AZM)
-    !              theta in [deg] incidence angle
-    !         output:
-    !              CMOD5_N NORMALIZED BACKSCATTER (LINEAR)
-    !
-    !        All inputs must be Numpy arrays of equal sizes
-    !
-    !     A. STOFFELEN              MAY  1991 ECMWF  CMOD4
-    !     A. STOFFELEN, S. DE HAAN  DEC  2001 KNMI   CMOD5 PROTOTYPE
-    !     H. HERSBACH               JUNE 2002 ECMWF  COMPLETE REVISION
-    !     J. de Kloe                JULI 2003 KNMI,  rewritten in fortan90
-    !     A. Verhoef                JAN  2008 KNMI,  CMOD5 for neutral winds
-    !     K.F.Dagestad              OCT 2011 NERSC,  Vectorized Python version
-    !---------------------------------------------------------------------
-       '''
-        
-    from numpy import cos, exp, tanh, array
-    
-    DTOR   = 57.29577951
-    THETM  = 40.
+
+def cmod5n_forward(v, phi, theta):
+    """cmod5n_forward(v, phi, theta)
+    Parameters:
+        v: float, numpy.array
+            2D array with wind velocities in [m/s] (always >= 0)
+        phi: float, numpy.array
+            2D array with angles between azimuth and wind direction in [deg] (= D - AZM)
+        theta: float, numpy.array
+            2D array with incidence angles in [deg]
+
+    Returns:
+        cmod_n:
+            Normalized backscatter (linear)
+
+    A. STOFFELEN              MAY  1991 ECMWF  CMOD4
+    A. STOFFELEN, S. DE HAAN  DEC  2001 KNMI   CMOD5 PROTOTYPE
+    H. HERSBACH               JUNE 2002 ECMWF  COMPLETE REVISION
+    J. de Kloe                JULI 2003 KNMI,  rewritten in fortan90
+    A. Verhoef                JAN  2008 KNMI,  CMOD5 for neutral winds
+    K.F.Dagestad              OCT 2011 NERSC,  Vectorized Python version
+    """
+
+    DTOR = 57.29577951
+    THETM = 40.
     THETHR = 25.
-    ZPOW   = 1.6
+    ZPOW = 1.6
     
     # NB: 0 added as first element below, to avoid switching from 1-indexing to 0-indexing
-    C = [0, -0.6878, -0.7957,  0.3380, -0.1728, 0.0000,  0.0040, 0.1103, 0.0159, 
-          6.7329,  2.7713, -2.2885, 0.4971, -0.7250, 0.0450, 
-          0.0066,  0.3222,  0.0120, 22.7000, 2.0813,  3.0000, 8.3659,
-          -3.3428,  1.3236,  6.2437,  2.3893, 0.3249,  4.1590, 1.6930]
+    C = [0, -0.6878, -0.7957,  0.3380, -0.1728, 0.0000,  0.0040, 0.1103, 0.0159, 6.7329,  2.7713,
+         -2.2885, 0.4971, -0.7250, 0.0450,  0.0066,  0.3222,  0.0120, 22.7000, 2.0813,  3.0000,
+         8.3659,  -3.3428,  1.3236,  6.2437,  2.3893, 0.3249,  4.1590, 1.6930]
+
     Y0 = C[19]
     PN = C[20]
-    A  = C[19]-(C[19]-1)/C[20]
+    A = C[19] - (C[19] - 1) / C[20]
 
-    B  = 1./(C[20]*(C[19]-1.)**(3-1))
+    B = 1. / (C[20] * (C[19] - 1.) ** (3-1))
 
-#  !  ANGLES
-    FI=phi/DTOR
+    # ANGLES
+    FI = phi/DTOR
     CSFI = cos(FI)
-    CS2FI= 2.00 * CSFI * CSFI - 1.00
+    CS2FI = 2.00 * CSFI * CSFI - 1.00
 
-    X  = (theta - THETM) / THETHR
-    XX = X*X
+    X = (theta - THETM) / THETHR
+    XX = X * X
 
-    #  ! B0: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
-    A0 =C[ 1]+C[ 2]*X+C[ 3]*XX+C[ 4]*X*XX
-    A1 =C[ 5]+C[ 6]*X
-    A2 =C[ 7]+C[ 8]*X
+    # B0: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
+    A0 = C[1] + C[2] * X + C[3] * XX + C[4] * X * XX
+    A1 = C[5] + C[6] * X
+    A2 = C[7] + C[8] * X
 
-    GAM=C[ 9]+C[10]*X+C[11]*XX
-    S0 =C[12]+C[13]*X
+    GAM = C[9] + C[10] * X + C[11] * XX
+    S0 = C[12] + C[13] * X
     
     # V is missing! Using V=v as substitute, this is apparently correct
-    V=v
-    S = A2*V
+    V = v
+    S = A2 * V
     S_vec = S.copy() 
-    SlS0 = [S_vec<S0]
-    S_vec[SlS0]=S0[SlS0]
-    A3=1./(1.+exp(-S_vec))
-    SlS0 = (S<S0)
-    A3[SlS0]=A3[SlS0]*(S[SlS0]/S0[SlS0])**( S0[SlS0]*(1.- A3[SlS0]))
+    SlS0 = [S_vec < S0]
+    S_vec[SlS0] = S0[SlS0]
+    A3 = 1. / (1. + exp(-S_vec))
+    SlS0 = (S < S0)
+    A3[SlS0] = A3[SlS0] * (S[SlS0] / S0[SlS0]) ** (S0[SlS0] * (1. - A3[SlS0]))
     #A3=A3*(S/S0)**( S0*(1.- A3))
-    B0=(A3**GAM)*10.**(A0+A1*V)
+    B0 = (A3 ** GAM) * 10. ** (A0 + A1 * V)
         
-    #  !  B1: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
-    B1 = C[15]*V*(0.5+X-tanh(4.*(X+C[16]+C[17]*V)))
-    B1 = C[14]*(1.+X)- B1
-    B1 = B1/(exp( 0.34*(V-C[18]) )+1.)
-
-    #  !  B2: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
-    V0 = C[21] + C[22]*X + C[23]*XX
-    D1 = C[24] + C[25]*X + C[26]*XX
-    D2 = C[27] + C[28]*X
-
-    V2 = (V/V0+1.)
-    V2ltY0 = V2<Y0
-    V2[V2ltY0] = A+B*(V2[V2ltY0]-1.)**PN
-    B2 = (-D1+D2*V2)*exp(-V2)
-
-    #  !  CMOD5_N: COMBINE THE THREE FOURIER TERMS
-    CMOD5_N = B0*(1.0+B1*CSFI+B2*CS2FI)**ZPOW
+    # B1: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
+    B1 = C[15] * V * (0.5 + X - tanh(4. * (X + C[16] + C[17] * V)))
+    B1 = C[14] * (1. + X) - B1
+    B1 = B1 / (exp(0.34 * (V - C[18])) + 1.)
+
+    # B2: FUNCTION OF WIND SPEED AND INCIDENCE ANGLE
+    V0 = C[21] + C[22] * X + C[23] * XX
+    D1 = C[24] + C[25] * X + C[26] * XX
+    D2 = C[27] + C[28] * X
+
+    V2 = (V / V0 + 1.)
+    V2ltY0 = V2 < Y0
+    V2[V2ltY0] = A + B * (V2[V2ltY0] - 1.) ** PN
+    B2 = (-D1 + D2 * V2) * exp(-V2)
+
+    # CMOD5_N: COMBINE THE THREE FOURIER TERMS
+    CMOD5_N = B0 * (1.0 + B1 * CSFI + B2 * CS2FI) ** ZPOW
+
     return CMOD5_N
     
 
 def cmod5n_inverse(sigma0_obs, phi, incidence, iterations=10):
-    '''!     ---------
-    !     cmod5n_inverse(sigma0_obs, phi, incidence, iterations)
-    !         inputs:
-    !              sigma0_obs     Normalized Radar Cross Section [linear units]
-    !              phi   in [deg] angle between azimuth and wind direction
-    !                    (= D - AZM)
-    !              incidence in [deg] incidence angle
-    !              iterations: number of iterations to run
-    !         output:
-    !              Wind speed, 10 m, neutral stratification 
-    !
-    !        All inputs must be Numpy arrays of equal sizes
-    !
-    !    This function iterates the forward CMOD5N function
-    !    until agreement with input (observed) sigma0 values   
-    !---------------------------------------------------------------------
-       '''
+    """The function iterates the forward CMOD5N <cmod5n_forward> function until agreement with input
+     (observed) sigma0 values
+
+    Parameters:
+        sigma0_obs: float, numpy.array
+             2D array with Normalized Radar Cross Section (NRCS) [linear units]
+        phi: float, numpy.array
+            2D array with angles between azimuth and wind direction in [deg] (= D - AZM)
+        incidence: float, numpy.array
+            incidence angles in [deg]
+        iterations: int
+            number of iterations to run
+
+    Returns:
+        v: float, numpy.array
+            2D array with wind speeds at 10 m, neutral stratification
+    """
+
     from numpy import ones, array
     
     # First guess wind speed
-    V = array([10.])*ones(sigma0_obs.shape);
-    step=10.
+    V = array([10.])*ones(sigma0_obs.shape)
+    step = 10.
     
     # Iterating until error is smaller than threshold
     for iterno in range(1, iterations):
         #print iterno
         sigma0_calc = cmod5n_forward(V, phi, incidence)
-        ind = sigma0_calc-sigma0_obs>0
+        ind = sigma0_calc-sigma0_obs > 0
         V = V + step
-        V[ind] = V[ind] - 2*step 
-        step = step/2
+        V[ind] = V[ind] - 2 * step
+        step = step / 2
 
-    #mdict={'s0obs':sigma0_obs,'s0calc':sigma0_calc}
-    #from scipy.io import savemat
-    #savemat('s0test',mdict)
-        
     return V