Adding algorithm delta-star transformation

DIRECTORY.md

@@ -422,6 +422,7 @@
   * [Resistor Color Code](electronics/resistor_color_code.py)
   * [Resistor Equivalence](electronics/resistor_equivalence.py)
   * [Resonant Frequency](electronics/resonant_frequency.py)
+  * [Star Delta Transform](electronics/star_delta_transform.py)
   * [Wheatstone Bridge](electronics/wheatstone_bridge.py)
 
 ## File Transfer

electronics/star_delta_transform.py

@@ -0,0 +1,125 @@
+"""
+In electrical engineering, the Y-Δ transform, also written wye-delta and also known by
+many other names, is a mathematical technique to simplify the analysis of an electrical
+network.
+The name derives from the shapes of the circuit diagrams, which look respectively like
+the letter Y and the Greek capital letter Δ. This circuit transformation theory was
+published by Arthur Edwin Kennelly in 1899. It is widely used in analysis of three-phase
+electric power circuits.
+
+The Y-Δ transform can be considered a special case of the star-mesh transform for three
+resistors. In mathematics, the Y-Δ transform plays an important role in theory of
+circular planar graphs.
+
+Source: https://en.wikipedia.org/wiki/Y-%CE%94_transform
+"""
+
+from sys import exit
+from unittest import mock
+
+
+def delta_to_wye(r: list) -> dict:
+    """
+    >>> delta_to_wye([2.0, 3.0, 4.0])
+    {'r1': 1.3333333333333333, 'r2': 0.8888888888888888, 'r3': 0.6666666666666666}
+    """
+    r_wye: dict = {}
+    ra, rb, rc = r[0], r[1], r[2]
+    r_wye.update({"r1": rb * rc / (ra + rb + rc)})
+    r_wye.update({"r2": ra * rc / (ra + rb + rc)})
+    r_wye.update({"r3": ra * rb / (ra + rb + rc)})
+    return r_wye
+
+
+def wye_to_delta(r: list) -> dict:
+    """
+    >>> wye_to_delta([2.0, 3.0, 4.0])
+    {'ra': 13.0, 'rb': 8.666666666666666, 'rc': 6.5}
+    """
+    r1, r2, r3 = r[0], r[1], r[2]
+    r_delta: dict = {}
+    r_delta.update({"ra": (r1 * r2 + r2 * r3 + r3 * r1) / r1})
+    r_delta.update({"rb": (r1 * r2 + r2 * r3 + r3 * r1) / r2})
+    r_delta.update({"rc": (r1 * r2 + r2 * r3 + r3 * r1) / r3})
+    return r_delta
+
+
+def transform(mode: int, r: list) -> dict:
+    """
+    >>> transform(1, [4.0, 5.0, 6.0])
+    {'r1': 2.0, 'r2': 1.6, 'r3': 1.3333333333333333}
+
+    >>> transform(2, [4.0, 5.0, 6.0])
+    {'ra': 18.5, 'rb': 14.8, 'rc': 12.333333333333334}
+    """
+    r_transformed = {}
+    if mode == 1:
+        r_transformed = delta_to_wye(r)
+    elif mode == 2:
+        r_transformed = wye_to_delta(r)
+    return r_transformed
+
+
+def get_type_transform():
+    mode: int = 0
+    try:
+        print("""
+        1. From delta to wye
+        2. From wye to delta
+        """)
+        mode = int(input("? --> "))
+    except ValueError:
+        print("Invalid Value. Only int inputs are accepted")
+        exit()
+    return mode
+
+
+def get_resistors_values(mode: int) -> list:
+    r: list = []
+    print("Select conversion (type 1 or 2)")
+    try:
+        if mode == 1:
+            r = list(
+                map(
+                    float, input("Resistant values (format ra rb rc): ").strip().split()
+                )
+            )[:3]
+        elif mode == 2:
+            r = list(
+                map(
+                    float, input("Resistant values (format r1 r2 r3): ").strip().split()
+                )
+            )[:3]
+        else:
+            print("Incorrect selected option. Valid option 1 or 2")
+    except ValueError:
+        print("Invalid Value. Only int inputs are accepted")
+        exit()
+    return r
+
+
+def test_get_type_transformation() -> None:
+    with mock.patch("builtins.input", return_value="1"):
+        m = get_type_transform()
+        assert m == 1
+
+
+def test_get_resistors_values() -> None:
+    with mock.patch("builtins.input", return_value="2 4 8"):
+        r = get_resistors_values(2)
+        assert r == [2.0, 4.0, 8.0]
+
+
+def main() -> None:
+    print("star - delta transform")
+    mode = get_type_transform()
+    r = get_resistors_values(mode)
+    r_transformed = transform(mode, r)
+    print(f"Result: '{r_transformed}'")
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()
+    main()