feat: menambahkan algoritma rieman

Author: Ateng-labrador

math/rieman_integral.py

@@ -0,0 +1,62 @@
+from typing import Callable
+import math
+
+
+def rieman_integral(f: Callable[[float], float],
+                    a: float,
+                    b: float,
+                    n: int,
+                    approx: str) -> float:
+    """
+    >>> rieman_integral(math.sin,0,math.pi/2,100,"tengah")
+    1.0000102809119051
+    >>> rieman_integral(math.sin,0,math.pi/2,100,"kanan")
+    1.007833419873582
+    >>> rieman_integral(math.sin,0,math.pi/2,100,"kiri")
+    0.9921254566056331
+    """
+    delta_x = (b - a) / n
+    sigma = 0.0
+    approx = approx.lower()
+
+    for i in range(n):
+        left = a + i * delta_x
+        right = left + delta_x
+
+        if approx == "kiri":
+            x_i = left
+        elif approx == "kanan":
+            x_i = right
+        elif approx == "tengah":
+            x_i = left + 0.5 * delta_x
+        else:
+            raise ValueError("masukkan approx benar")
+
+        sigma += f(x_i)
+
+    return delta_x * sigma
+
+
+def main(args=None):
+    import doctest
+
+    doctest.testmod()
+
+    # persamaan x
+    def f(x):
+        return x
+    print(rieman_integral(f, 0, 1, 1, "tengah"))  # 0.5
+
+    # persamaan 4/(1+x^2)
+    def f(x):
+        return (4) / (1 + x**2)
+    print(rieman_integral(f, 0, 1, 1000, "tengah"))  # 3.1415927369231227
+
+    # Persamaan sin
+    def f(x):
+        return math.sin(x)
+    print(rieman_integral(f, 0, math.pi / 2, 100, "kiri"))  # 0.9921254566056331
+
+
+if __name__ == "__main__":
+    main()