a lot of new files again

c_programs/Makefile

@@ -6,3 +6,6 @@ all:
 
 sequence_generator: sequence_generator.c
 	$(CC) $(CFLAGS) sequence_generator.c -o sequence_generator
+
+simple: simple_c_example.c
+	$(CC) $(CFLAGS) simple_c_example.c -o simple_c_example

c_programs/simple_c_example.c

@@ -0,0 +1,148 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void print_array(int* arr, int length) {
+  int i;
+  printf("[");
+  for (i = 0; i < length; i++) {
+    if (i > 0) {
+      printf(", ");
+    }
+    printf("%d", arr[i]);
+  }
+  printf("]");
+  printf("\n");
+}
+
+void delete_max(int** arr, int* length) {
+  /* TODO: write your code! */
+  int i;
+
+  int max_val = 0;
+  int max_idx = 0;
+
+  for (i = 0; i < *length; i++) {
+    int val = (*arr)[i];
+
+    if (max_val < val) {
+      max_val = val;
+      max_idx = i;
+    }
+  }
+
+  printf("max_val: %d\n", max_val);
+  printf("max_idx: %d\n", max_idx);
+
+  for (i = max_idx; i < *length-1; i++) {
+    (*arr)[i] = (*arr)[i+1];
+  }
+
+  *arr = realloc(*arr, sizeof(int) * (*length-1));
+  (*length)--;
+}
+
+void mirror_array(int* arr, int length) {
+  /* TODO: write your code! */
+  int len = length / 2;
+  printf("len: %d\n", len);
+
+  int i;
+  for (i = 0; i < len; i++) {
+    int temp = arr[i];
+    arr[i] = arr[length-1-i];
+    arr[length-1-i] = temp;
+  }
+}
+
+int concat_arrays(int** arr, int* len, int* arr1, int len1, int* arr2, int len2) {
+  /* TODO: write your code! */
+  *len = len1 + len2;
+  *arr = malloc(*len * sizeof(int));
+
+  if (*arr == NULL) {
+    *len = 0;
+    return -1;
+  }
+
+  int i;
+  for (i = 0; i < len1; i++) {
+    (*arr)[i] = arr1[i];
+  }
+  for (i = 0; i < len2; i++) {
+    (*arr)[i+len1] = arr2[i];
+  }
+
+  return 0;
+}
+
+int main(int argc, char* argv[]) {
+  /* TODO: write your code! */
+  int len1 = 5;
+  int* arr1 = malloc(len1 * sizeof(int));
+
+  if (arr1 == NULL) {
+    printf("NO MEMORY!\n");
+    return -1;
+  }
+
+  arr1[0] = 2;
+  arr1[1] = 1;
+  arr1[2] = 8;
+  arr1[3] = 4;
+  arr1[4] = 6;
+
+  int len2 = 4;
+  int* arr2 = malloc(len1 * sizeof(int));
+
+  if (arr2 == NULL) {
+    free(arr1);
+    printf("NO MEMORY!\n");
+    return -1;
+  }
+
+  arr2[0] = 21;
+  arr2[1] = 11;
+  arr2[2] = 81;
+  arr2[3] = 41;
+
+
+  printf("arr1:\n");
+  print_array(arr1, len1);
+
+  int excersice_num = 2;
+
+  switch (excersice_num) {
+    case 0:
+      delete_max(&arr1, &len1);
+      printf("arr1 after delete max:\n");
+      print_array(arr1, len1);
+      break;
+
+    case 1:
+      mirror_array(arr1, len1);
+      printf("arr1 after mirror:\n");
+      print_array(arr1, len1);
+      break;
+
+    case 2:
+      printf("arr2:\n");
+      print_array(arr2, len2);
+
+      int* arr_con = NULL;
+      int len_con = 0;
+      int ret = concat_arrays(&arr_con, &len_con, arr1, len1, arr2, len2);
+      if (ret) {
+        free(arr1);
+        free(arr2);
+        printf("NO MEMORY!\n");
+        return -2;
+      }
+
+      printf("after:\nlen_con: %d\n", len_con);
+      printf("arr_con:\n");
+      print_array(arr_con, len_con);
+      break;
+  }
+
+  return 0;
+}

combinatorics/different_combinations.py

@@ -3,6 +3,7 @@
 # -*- coding: utf-8 -*-
 
 import dill
+import os
 import sys
 
 import numpy as np
@@ -55,6 +56,31 @@ def get_all_combinations_increment(m, n):
     return arr
 
 
+# n ... amount of states
+def get_permutation_table(n, same_pos=True):
+    if n == 1:
+        return np.array([[1]], dtype=np.uint8)
+    arr = np.array([[0, 1], [1, 0]], dtype=np.uint8)
+
+    p = 2
+    for i in range(3, n+1):
+        arr_new = np.zeros((p*i, i), dtype=np.uint8)
+
+        for j in range(0, i):
+            arr_new[p*j:p*(j+1), 0] = (j-1) % i
+            arr_new[p*j:p*(j+1), 1:] = (arr+j) % i
+
+        p *= i
+        arr = arr_new
+
+    arr = np.sort(arr.reshape((-1, )).view(','.join(['u1']*n))).view('u1').reshape((-1, n))
+
+    if not same_pos:
+        arr = arr[~np.any(arr == np.arange(0, n), axis=1)]
+
+    return arr
+
+
 # m ... max num for state
 # n ... amount of states
 def get_amount_of_increment_combinations(m, n):

difference_equation/example1.py

@@ -0,0 +1,45 @@
+#! /usr/bin/python3.6
+
+# -*- coding: utf-8 -*-
+
+import dill
+import functools
+import sys
+import time
+
+import numpy as np
+
+import matplotlib.pyplot as plt
+
+if __name__ == "__main__":
+    # c1 = 1.16/209
+    P_B = 50
+    Q_B = 209
+
+    V_d = 0.206
+    V_B = 50
+
+    c1 = P_B / Q_B
+    c2 = V_d / V_B
+
+    dt = 0.1
+    theta1 = 10
+
+    theta = 70
+
+    xs = [0]
+    ys = [theta]
+
+    t = 0
+    for _ in range(0, 30000):
+        theta = theta + (c1+(theta1-theta)*c2)*dt
+        t += dt
+        xs.append(t)
+        ys.append(theta)
+
+    print("xs: {}".format(xs))
+    print("ys: {}".format(ys))
+
+    plt.figure()
+    plt.plot(xs, ys)
+    plt.show()