import numpy as np
from scipy.stats import gamma
import matplotlib.pyplot as plt

plt.style.use('ggplot')
fig, ax = plt.subplots(facecolor="w", figsize=(10, 5))

# x axis
x = np.linspace(0, 8, 100)

# draw graph
plt.plot(x, gamma.pdf(x, 1, 0, scale=1/1), label='alpha=1, beta=1')
plt.plot(x, gamma.pdf(x, 1, 0, scale=1/2), label='alpha=1, beta=2')
plt.plot(x, gamma.pdf(x, 2, 0, scale=1/2), label='alpha=2, beta=2')
plt.plot(x, gamma.pdf(x, 3, 0, scale=1/2), label='alpha=3, beta=2')
plt.plot(x, gamma.pdf(x, 5, 0, scale=1/2), label='alpha=5, beta=2')
plt.plot(x, gamma.pdf(x, 10, 0, scale=1/1), label='alpha=5, beta=1')
plt.legend()
plt.xlabel("x")
plt.ylabel("Probability density")
plt.show()

import numpy as np
from scipy.stats import gamma
import matplotlib
import matplotlib.pyplot as plt
from matplotlib import animation, rc
from matplotlib.animation import FuncAnimation

rc('animation', html='html5')
np.random.seed(5)

# Set up formatting for the movie files
Writer = animation.writers['ffmpeg']
writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1800)

prob_vals = np.arange(start=0.1, stop=10.01, step=0.2)

plt.style.use('ggplot')
fig, ax = plt.subplots(facecolor="w", figsize=(15, 5))

# x axis
x = np.linspace(0, 10, 100)

def update(i):
    p = prob_vals[i]

    # alpha graph
    plt.subplot(1, 2, 1)
    plt.cla()
    plt.plot(x, gamma.pdf(x, round(p, 1), 0, scale=1/2))
    # plt.plot(x, gamma.pdf(x, 2, 0, scale=1/round(p, 1)))
    plt.title(f'$alpha={str(round(p, 1))}, beta=2$', loc='left')
    plt.xlabel("x")
    plt.ylabel("Probability density")
    plt.ylim(0, 4.1)
    plt.xticks(ticks=[0, 10]) # x axis ticks

    # beta graph
    plt.subplot(1, 2, 2)
    plt.cla()
    plt.plot(x, gamma.pdf(x, 2, 0, scale=1/round(p, 1)))
    plt.title(f'$alpha=2, beta={str(round(p, 1))}$', loc='left')
    plt.xlabel("x")
    plt.ylabel("Probability density")
    plt.ylim(0, 4.1)
    plt.xticks(ticks=[0, 10]) # x axis ticks

anime_prob = FuncAnimation(fig, update, frames=len(prob_vals), interval=1000)
anime_prob.save('gamma_dist.gif', writer='pillow', fps=10)