From c53e9fe25866376d1b3086579c01725444a04702 Mon Sep 17 00:00:00 2001
From: Fabian <@>
Date: Tue, 26 Jul 2022 21:27:23 +0200
Subject: 0f1, Code ueberarbeitet

---
 buch/papers/0f1/listings/kettenbruchIterativ.c  | 16 +++++--
 buch/papers/0f1/listings/kettenbruchRekursion.c | 22 ++++++----
 buch/papers/0f1/listings/potenzreihe.c          | 56 +++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 11 deletions(-)

(limited to 'buch/papers/0f1/listings')

diff --git a/buch/papers/0f1/listings/kettenbruchIterativ.c b/buch/papers/0f1/listings/kettenbruchIterativ.c
index befea8e..d897b8f 100644
--- a/buch/papers/0f1/listings/kettenbruchIterativ.c
+++ b/buch/papers/0f1/listings/kettenbruchIterativ.c
@@ -1,5 +1,13 @@
-static double fractionRekursion0f1(const double c, const double x, unsigned int n)
+/**
+  * @brief Calculates the Hypergeometric Function 0F1(;b;z)
+  * @param b0 in 0F1(;b0;z)
+  * @param z in 0F1(;b0;z)
+  * @param n number of itertions (precision)
+  * @return Result
+  */
+static double fractionRekursion0f1(const double c, const double z, unsigned int n)
 {
+    //declaration
     double a = 0.0;
     double b = 0.0;
     double Ak = 0.0;
@@ -21,15 +29,15 @@ static double fractionRekursion0f1(const double c, const double x, unsigned int
         else if (k == 1)
         {
             a = 1.0; //a1
-            b = x/c; //b1
+            b = z/c; //b1
             //recursion fomula for A1, B1
             Ak = a * Ak_1 + b * 1.0;
             Bk = a * Bk_1;
         }
         else
         {
-            a = 1 + (x / (k * ((k - 1) + c)));//ak
-            b = -(x / (k * ((k - 1) + c)));   //bk
+            a = 1 + (z / (k * ((k - 1) + c)));//ak
+            b = -(z / (k * ((k - 1) + c)));   //bk
             //recursion fomula for Ak, Bk
             Ak = a * Ak_1 + b * Ak_2;
             Bk = a * Bk_1 + b * Bk_2;
diff --git a/buch/papers/0f1/listings/kettenbruchRekursion.c b/buch/papers/0f1/listings/kettenbruchRekursion.c
index 958d4e1..143683f 100644
--- a/buch/papers/0f1/listings/kettenbruchRekursion.c
+++ b/buch/papers/0f1/listings/kettenbruchRekursion.c
@@ -1,18 +1,26 @@
-static double fractionIter0f1(const double b0, const double z, unsigned int n)
+/**
+  * @brief Calculates the Hypergeometric Function 0F1(;c;z)
+  * @param c in 0F1(;c;z)
+  * @param z in 0F1(;c;z)
+  * @param k number of itertions (precision)
+  * @return Result
+  */
+static double fractionIter0f1(const double c, const double z, unsigned int k)
 {
+    //declaration
     double a = 0.0;
     double b = 0.0;
-    double abn = 0.0;
+    double abk = 0.0;
     double temp = 0.0;
 
-    for (; n > 0; --n)
+    for (; k > 0; --k)
     {
-        abn = z / (n * ((n - 1) + b0));  //abn = ak, bk
+        abk = z / (k * ((k - 1) + c));  //abk = ak, bk
         
-        a = n > 1 ? (1 + abn) : 1;  //a0, a1
-        b = n > 1 ? -abn : abn;     //b1
+        a = k > 1 ? (1 + abk) : 1;  //a0, a1
+        b = k > 1 ? -abk : abk;     //b1
 
-        temp = b / (a + temp); 
+        temp = b / (a + temp);      ////bk / (ak + last result)
     }
 
     return a + temp;   //a0 + temp
diff --git a/buch/papers/0f1/listings/potenzreihe.c b/buch/papers/0f1/listings/potenzreihe.c
index bfaa0e3..3eb9b86 100644
--- a/buch/papers/0f1/listings/potenzreihe.c
+++ b/buch/papers/0f1/listings/potenzreihe.c
@@ -1,5 +1,61 @@
 #include <math.h>
 
+/**
+  * @brief Calculates pochhammer
+  * @param (a+n-1)!
+  * @return Result
+  */
+static double pochhammer(const double x, double n)
+{
+    double temp = x;
+
+    if (n > 0)
+    {
+        while (n > 1)
+        {
+            temp *= (x + n - 1);
+            --n;
+        }
+
+        return temp;
+    }
+    else
+    {
+        return 1;
+    }
+}
+
+/**
+  * @brief Calculates the Factorial
+  * @param n!
+  * @return Result
+  */
+static double fac(int n)
+{
+    double temp = n;
+
+    if (n > 0)
+    {
+        while (n > 1)
+        {
+            --n;
+            temp *= n;
+        }
+        return temp;
+    }
+    else
+    {
+        return 1;
+    }
+}
+
+/**
+  * @brief Calculates the Hypergeometric Function 0F1(;b;z)
+  * @param b0 in 0F1(;b0;z)
+  * @param z in 0F1(;b0;z)
+  * @param n number of itertions (precision)
+  * @return Result
+  */
 static double powerseries(const double b, const double z, unsigned int n)
 {
     double temp = 0.0;
-- 
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