Added bisection.py

python/nonlinear-equations/bisection.py

@@ -0,0 +1,17 @@
+import numpy as np
+
+def bisection(functie, a, b, tol, nmax):
+    # we search for the approximate solution
+    # in a limited amount of steps
+    for n in range(nmax):
+        # we split the interval in which we search the solution and search at it's half
+        c = a + (b - a) / 2
+        # if we find the solution or the interval in which we search is very small 
+        # we return the solution and the number of steps in which we found it
+        if functie(c) == 0 or (b - a) / 2 < tol:
+            return (c, n)
+        # modify the searching interval
+        if np.sign(functie(c)) * np.sign(functie(a)) < 0:
+            b = c
+        else:
+            a = c