added wind_resource.py

topfarm/cost_models/utils/wind_resource.py

+'''
+Created on 19/04/2018
+
+@author: Mads
+'''
+import numpy as np
+class WindResource(object):
+    def __init__(self,f,a,k,ti):
+        self.f = f
+        self.a = a
+        self.k = k
+        self.ti = ti
+    
+    def weibull_weight(self, ws):
+        cdf = lambda ws, A=self.A,k=self.k : 1 - np.exp(-(ws / A) ** k)
+        dws = np.diff(ws,0)
+        return cdf(ws+dws) - cdf(ws-dws)  
+        
+    def __call__(self, turbine_positions, wdir, wsp):
+        
+        WS = np.broadcast_to(wsp, (len(turbine_positions), len(wdir),len(wsp)))
+        weight = self.weibull_weight(self.a, self.k, WS)
+        #TODO: add weight from wdir dist
+        return WS, np.zeros_like(WS)+self.ti, weight
+