그래프 그리는 코드

1. y=f(x) 

#y=f(x)
from numpy import *
import matplotlib.pyplot as plt

xrange = [0,10]

def f(x):
	return sin(x)

x_line = arange(xrange[0], xrange[1], 0.1) # 0.1 간격으로 점을 찍는다
y_line = f(x_line)

plt.plot(x_line, y_line)

plt.xlabel('x'); plt.ylabel('y'); plt.title('y=f(x)')
plt.show()

 

2. f(x,y)=0

from numpy import *
import matplotlib.pyplot as plt

def f(x,y):
    return 0.01*x**2+0.008*x*y-0.013*y**2+0.15*x+0.003*y+1.0097

x = arange(-10.0,10.0,0.1)
y = arange(-10.0,10.0,0.1)
X, Y = meshgrid(x,y)
plt.contour(x, y, f(X, Y), [0]);

# label(or legend)을 넣으려면
# cs = plt.contour(x, y, f(X, Y), [0]); plt.clabel(cs, fmt='%.1f');

 

3. z=f(x,y) in 3D

# prompt: plot z=f(x,y) in 3d 

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
from matplotlib import cm
import numpy as np

def f(x, y):
    # Replace this with your desired function
    return 0.01*x**2+0.008*x*y-0.013*y**2+0.15*x+0.003*y+1.0097

# Create the figure and axes object for the 3D plot
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

# Generate the x, y, and z data
x = np.arange(-10, 10, 0.5)
y = np.arange(-10, 10, 0.5)
X, Y = np.meshgrid(x, y)
Z = f(X, Y)

# Plot the surface
surf = ax.plot_surface(X, Y, Z, cmap=cm.coolwarm)

# Add labels and a colorbar
ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('z')
fig.colorbar(surf, shrink=0.5, aspect=5)

# Show the plot
plt.show()

4. z=f(x,y) in 2D by contour

import numpy as np
import matplotlib.pyplot as plt
from math import *


fig = plt.figure()
ax = fig.add_subplot(111)

levels = np.arange(0,3,0.1)
x_cut = 100
y_cut = 100
x = np.linspace(-10.0, 10.0, x_cut)
y = np.linspace(-10.0, 10.0, y_cut)
X, Y = np.meshgrid(x,y)
F = np.zeros((y_cut, x_cut), dtype='float32')
for i in range(x_cut):
  for j in range(y_cut):
    a = x[i]
    b = y[j]
    F[i][j] = sqrt((sin(a/2))**2 + (sin(((a/2)+(sqrt(3)*b/2))/2))**2 + (sin(((-a/2)+(sqrt(3)*b/2))/2))**2 + \
      sqrt((((sin(a/2))**2 - (sin(((a/2)+(sqrt(3)*b/2))/2))**2)**2+ \
      ((sin(a/2))**2 - (sin(((-a/2)+(sqrt(3)*b/2))/2))**2)**2+ \
      ((sin(((a/2)+(sqrt(3)*b/2))/2))**2-(sin(((-a/2)+(sqrt(3)*b/2))/2))**2)**2)/2))
CS = plt.contour(X,Y,F,levels)
ax.set_aspect('equal', adjustable='box')

for i in range(len(levels)):
    CS.collections[i].set_label(levels[i])

plt.colorbar()

plt.show()