HARKinterpolation.py 文件源码

def _derX(self,x,y):
        '''
        Returns the derivative with respect to x of the interpolated function
        at each value in x,y. Only called internally by HARKinterpolator2D.derivativeX.
        '''
        if _isscalar(x):
            y_pos = max(min(np.searchsorted(self.y_list,y),self.y_n-1),1)
            alpha = (y - self.y_list[y_pos-1])/(self.y_list[y_pos] - self.y_list[y_pos-1])
            dfdx = (1-alpha)*self.xInterpolators[y_pos-1]._der(x) + alpha*self.xInterpolators[y_pos]._der(x)
        else:
            m = len(x)
            y_pos = np.searchsorted(self.y_list,y)
            y_pos[y_pos > self.y_n-1] = self.y_n-1
            y_pos[y_pos < 1] = 1
            dfdx = np.zeros(m) + np.nan
            if y.size > 0:
                for i in xrange(1,self.y_n):
                    c = y_pos == i
                    if np.any(c):
                        alpha = (y[c] - self.y_list[i-1])/(self.y_list[i] - self.y_list[i-1])
                        dfdx[c] = (1-alpha)*self.xInterpolators[i-1]._der(x[c]) + alpha*self.xInterpolators[i]._der(x[c])
        return dfdx