fourier series generator and visualizer

fourier_series.py

@@ -0,0 +1,65 @@
+from sympy import *
+import numpy as np
+import matplotlib.pyplot as plt
+
+
+def fourier_series_(func, start, end):
+    n = symbols("n")
+    T = end - start
+    cos_term = cos((2 * n * pi * x) / T)
+    sin_term = sin((2 * n * pi * x) / T)
+
+    a0 = 2 / T * (integrate(func, (x, start, end)).doit())
+
+    an = 2 / T * (integrate(func * cos_term, (x, start, end)).doit()) * cos_term
+    bn = 2 / T * (integrate(func * sin_term, (x, start, end)).doit()) * sin_term
+
+    return a0 + an + bn
+
+
+def fourier_visualizer(func, start, end, terms=6, repeat=1, dir=1):
+    n = symbols("n")
+    T = end - start
+    cos_term = cos((2 * n * pi * x) / T)
+    sin_term = sin((2 * n * pi * x) / T)
+
+    a0 = 2 / T * (integrate(func, (x, start, end)).doit())
+
+    an = 2 / T * (integrate(func * cos_term, (x, start, end)).doit()) * cos_term
+    bn = 2 / T * (integrate(func * sin_term, (x, start, end)).doit()) * sin_term
+
+    if dir > 0:
+        x_axis = np.linspace(float(start), float(start + T * repeat), 100)
+    else:
+        x_axis = np.linspace(float(end - (T * repeat)), float(end), 100)
+    y_axis = []
+
+    for i in range(terms):
+        an_i = an.subs(n, i)
+        bn_i = bn.subs(n, i)
+
+        if i > 0:
+            y_axis.append(
+                tmp := np.vectorize(
+                    lambda value: float(an_i.subs(x, value) + bn_i.subs(x, value))
+                )(x_axis)
+                + y_axis[i - 1]
+            )
+        else:
+            y_axis.append(
+                tmp := np.vectorize(
+                    lambda value: float(an_i.subs(x, value) + bn_i.subs(x, value) + a0)
+                )(x_axis)
+            )
+        plt.plot(x_axis, y_axis[i])
+    plt.show()
+
+
+x = symbols("x")
+func = eval(input("Enter Function to be Plot\n\tf(x) = "))
+start = float(input("Enter start of period: "))
+end = float(input("Enter end of period: "))
+repeat = int(input("Repeat the period how many time [1]: ") or "1")
+direction = int(input("Repeat in +ve or -ve [1]: ") or "1")
+
+fourier_visualizer(func, start, end, repeat=repeat, dir=direction)