summer update

math_utils.py

@@ -0,0 +1,122 @@
+
+# Maybe make a non-square rooted function for comparison (faster)
+from uniquelist import uniquelist
+import math
+
+
+def atan2_inv(y_diff, x_diff):
+    '''Returns atan2 in inverted y-axis in degrees'''
+    return math.degrees(math.atan2(-y_diff, x_diff))
+# following constants are required for the next function
+
+
+def distance(point_1, point_2):
+    ''' distance between point_1 and point_2, where both are 2 member iterable'''
+    if (not len(point_1) == 2) or (not len(point_2) == 2):
+        raise TypeError("point_1 and point_2 both must be 2 member iterable")
+    diff_x = point_2[0] - point_1[0]
+    diff_y = point_2[1] - point_1[1]
+    return math.hypot(diff_x, diff_y)
+
+
+def vel_add(vel_1, vel_2):
+    ''' vel_1 and vel_2 both must be in (magnitude,direction_in_degree) format.
+        Returns in same format.'''
+    if (not len(vel_1) == 2) or (not len(vel_2) == 2):
+        raise TypeError("vel_1 and vel_2 both must be 2 member iterable")
+
+    vel_1_x = vel_1[0] * math.cos(math.radians(vel_1[1]))
+    vel_1_y = -vel_1[0] * math.sin(math.radians(vel_1[1]))
+
+    vel_2_x = vel_2[0] * math.cos(math.radians(vel_2[1]))
+    vel_2_y = -vel_2[0] * math.sin(math.radians(vel_2[1]))
+
+    vel_tot_x = vel_1_x + vel_2_x
+    vel_tot_y = vel_1_y + vel_2_y
+
+    vel_tot = (
+        math.hypot(vel_tot_x, vel_tot_y), atan2_inv(vel_tot_y, vel_tot_x))
+
+    return vel_tot
+
+
+def direction(point_1, point_2):
+    if (not len(point_1) == 2) or (not len(point_2) == 2):
+        raise TypeError("point_1 and point_2 both must be 2 member iterable")
+    diff_x = point_2[0] - point_1[0]
+    diff_y = point_2[1] - point_1[1]
+    return atan2_inv(diff_y, diff_x)
+
+UNION = 1
+INTERSECTION = 2
+DIFFERENCE = 3
+ADD = 4
+# for each member (usually objects) in the list, it is replaced by one of
+# its variables
+MAKE_IT_VARIABLE_LIST = 5
+
+
+def operation_on_lists(operation, list1, list2=None, variable_name=None):
+    ''' operation_on_lists(operation, list1, list2) -> list
+        Does operation involving list1 and list2.
+        variable_name is required only for MAKE_IT_VARIABLE_LIST operation. It is a string representing the variable name
+        Valid operations are UNION, INTERSECTION, DIFFERENCE, ADD, MAKE_IT_VARIABLE_list '''
+    def intersection():
+        if list2 is None:
+            raise TypeError("second argument i.e. list2 should be a list")
+        list_return = []
+        for temp1 in list1:
+            for temp2 in list2:
+                if temp1 == temp2:
+                    list_return.append(temp1)
+        return list_return
+
+    def union():
+        if list2 is None:
+            raise TypeError("second argument i.e. list2 should be a list")
+        list_return = uniquelist()
+        list_return.extend(list1)
+        list_return.extend(list2)
+        return list_return
+
+    def add():
+        if list2 is None:
+            raise TypeError("second argument i.e. list2 should be a list")
+        list_return = []
+        list_return.append(list1)
+        list_return.append(list2)
+        return list_return
+
+    def difference():
+        if list2 is None:
+            raise TypeError("second argument i.e. list2 should be a list")
+        list_return = []
+        list_intersection = intersection()
+        for temp1 in list1:
+            if temp1 not in list_intersection:
+                list_return.append(temp1)
+        return list_return
+
+    # for each member (usually objects) in the list, it is replaced by one of
+    # its variables
+    def make_it_variable_list():
+        if variable_name is None:
+            raise TypeError("variable_name should be a string")
+        if not list2 is None:
+            raise TypeError("list2 should be None")
+        return_list = [getattr(temp, variable_name) for temp in list1]
+
+    if operation == UNION:
+        return union()
+    elif operation == INTERSECTION:
+        return intersection()
+    elif operation == DIFFERENCE:
+        return difference()
+    elif operation == ADD:
+        return add()
+    elif operation == MAKE_IT_VARIABLE_LIST:
+        return make_it_variable_list()
+    else:
+        raise ValueError(
+            "Invalid operation name. Valid operations are UNION, INTERSECTION, DIFFERENCE.")
+# end of operation_on_lists()