From 302ac385b73bbb0f46ebb654b3c5bf4188c49133 Mon Sep 17 00:00:00 2001
From: Uwe Fechner <fechner@aenarete.eu>
Date: Sat, 7 May 2022 18:01:05 +0200
Subject: [PATCH] Three functions of windfield translated

---
 Project.toml             |  4 +++-
 src/AtmosphericModels.jl |  3 ++-
 src/windfield.jl         | 33 +++++++++++++++++----------------
 test/runtests.jl         |  6 ++++++
 4 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/Project.toml b/Project.toml
index 8887c0a..df5bb3b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,15 +4,17 @@ authors = ["Uwe Fechner <fechner@aenarete.eu> and contributors"]
 version = "0.1.0"
 
 [deps]
+HypergeometricFunctions = "34004b35-14d8-5ef3-9330-4cdb6864b03a"
 KiteUtils = "90980105-b163-44e5-ba9f-8b1c83bb0533"
 Parameters = "d96e819e-fc66-5662-9728-84c9c7592b0a"
 TestEnv = "1e6cf692-eddd-4d53-88a5-2d735e33781b"
 
 [compat]
-julia = "1.6, 1.7, 1.8"
 KiteUtils = "^0.3.4"
 Parameters = "^0.12"
 TestEnv = "1"
+HypergeometricFunctions = "0.3"
+julia = "1.6, 1.7, 1.8"
 
 [extras]
 BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
diff --git a/src/AtmosphericModels.jl b/src/AtmosphericModels.jl
index 17ab3d3..366ca67 100644
--- a/src/AtmosphericModels.jl
+++ b/src/AtmosphericModels.jl
@@ -1,6 +1,6 @@
 module AtmosphericModels
 
-using KiteUtils, Parameters
+using KiteUtils, Parameters, HypergeometricFunctions
 
 export AtmosphericModel, ProfileLaw, EXP, LOG, EXPLOG, FAST_EXP, FAST_LOG, FAST_EXPLOG
 export clear, calc_rho, calc_wind_factor
@@ -92,5 +92,6 @@ function calc_wind_factor(s::AM, height, ::Type{Val{6}})
         evalpoly(1/height, (1.0, 1735.2333827029918, 279373.0012683715))
 end
 
+include("windfield.jl")
 
 end
diff --git a/src/windfield.jl b/src/windfield.jl
index 62677f2..e2ac1e0 100644
--- a/src/windfield.jl
+++ b/src/windfield.jl
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This module provides methods to create a turbulent wind field and to read 
 the actual wind velocity vector as function of the 3d position
@@ -14,23 +13,25 @@ The code is based on the following papers:
    Engineering Mechanics 13(4), pp. 269-282.
 """
 
-# def pfq(z):
-#   return np.real(hyp2f1(1./3., 17./6., 4./3., z))
+function pfq(z)
+    _₂F₁(1. /3 , 17. /6, 4. /3, z)
+end
 
-# def calcSigma1(v_wind_gnd):
-#     # TODO: What is the meaning of this value ???
-#     v_height = calcWindHeight(v_wind_gnd, HUB_HEIGHT)
-#     sigma1 = I_REF * (0.75 * v_height + 5.6)
-#     return sigma1
+function calc_sigma1(am, v_wind_gnd)
+    v_height = v_wind_gnd * calc_wind_factor(am, am.set.avg_height, Val{Int(EXP)})
+    am.set.i_ref * (0.75 * v_height + 5.6)
+end
 
-# def nextpow2(i):
-#     """
-#     Find 2^n that is equal to or greater than i.
-#     """
-#     n = 1
-#     while n < i:
-#         n *= 2
-#     return n
+"""
+Find 2^n that is equal to or greater than i.
+"""
+function nextpow2(i)
+    n = 1
+    while n < i
+        n *= 2
+    end
+    n
+end
 
 # def calcFullName(v_wind_gnd, basename='windfield_4050_500', rel_sigma = 1.0):
 #     path = HOME+'/00PythonSoftware/KiteSim/Environment/'
diff --git a/test/runtests.jl b/test/runtests.jl
index a59632d..d9521f5 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -39,3 +39,9 @@ end
     clear(am)
 end
 
+@testset "windfield" begin
+    @test AtmosphericModels.pfq(0.1) ≈ 1.079576584249971
+    @test AtmosphericModels.calc_sigma1(am, 10.0) ≈ 2.181983002542761
+    @test AtmosphericModels.nextpow2(10) == 16
+end
+