为什么我的图形无法正确绘制？

Question

I'm trying to plot the graph y= 5*x - 300/x, but my ouptut is just a straight line and I don't understand why. Can anyone help? Thanks

xvls= []
Rvls= []

for x in range(-100,100,1):

    if x != 0:
       def R(x):
           f1 = 5*x
           f2 = 300/x
           f3 = f1+f2
           return f3
       error = 10
       while error >= 1e-6:
           error = R(x)-x
           x = x -error
           Rvls.append(R(x))
           xvls.append(x)
    else:
        print 0 

fig = plt.figure(figsize=(10,5))
xvls=np.linspace(-300,300, 25)
Rvls= np.linspace(-300,300, 25)
plt.subplot(1,2, 1)
plt.plot(xvls, Rvls, linestyle='-', marker='o', color='blue')
plt.xlabel('Distance from right hand pin')
plt.ylabel('Reaction force at left hand pin')
plt.title('The relationship between R(x) and x')
plt.rc('font', size=12)
plt.grid()

Answer 1

我认为linspace返回给定值之间的直线的值。

Answer 2

The lines

xvls=np.linspace(-300,300, 25)
Rvls= np.linspace(-300,300, 25)

override all the calculation you did before. You probably want to leave them out.

Answer 3

I would guess that the line f2 = 300/x is a possible culprit. If you're using Python 2.x f2 will evaluate to an integer because both 300 and x are integers. It wouldn't account for the fact that you get a straight line, but you haven't given a completely compilable code example to troubleshoot. Could you provide the minimum needed code that compiles and produces the problem?