matplotlib: ugly plots when using markers

Question

I have a little problem. I have a program that will draw wave function for a potential, and it looks fine when I use the option in plot (using pylab) '-' for instance: http://img41.imageshack.us/img41/8798/59138635.png

If I use 'o' i'll get: http://img16.imageshack.us/img16/3741/22378006.png

You see that it looks ugly :\

Is there a simple way to make the circles more spaced, or does that depends on the details of the code?

The code is:

from math import *
from scipy.special import *
from pylab import *
from scipy.linalg import *

firebrick=(178./255.,34./255.,34./255.)
indianred=(176./255.,23./255.,31./255.)
steelblue=(70./255.,130./255.,180./255.)
slategray1=(198./255.,226./255.,255./255.)
slategray4=(108./255.,123./255.,139./255.)
lavender=(230./255.,230./255.,230./255.)
cobalt=(61./255.,89./255.,171./255.)
midnightblue=(25./255.,25./255.,112./255.)
forestgreen=(34./255.,139./255.,34./255.)

#grid
Nmesh=512
L=4.0
dx=L/Nmesh
Xmax=L
x=arange(-L,L+0.0001,dx)
Npts=len(x)
numwav=2   #number of wave function that is being drawn

V=zeros([Npts],float)
for i in range(Npts):
    V[i]=x[i]**4

a=zeros([2,Npts-2],float)
wave=zeros([Npts],float)

wave1=zeros([Npts],float)
encor=3.0/4*(3.0/4)**(1.0/3)

#numerical solution
for i in range(1,Npts-1,1):
    a[0,i-1]= 1.0/dx**2+V[i]     #diagonal elements
    a[1,i-1]=-1.0/dx**2/2        #the elements below the diagonal
a[1,Npts-3]=-99.0                #element is not used
eig,vec=eig_banded(a,lower=1)    #routine that diagonalizes the tridiagonal matrix

for i in range(1,Npts-1,1):
    wave[i]=vec[i-1,numwav]
wave[0]=0.0             #wave function has the value zero on the first point on the grid
wave[Npts-1]=0.0        #wave function has the value zero on the last point on the grid

wave=150*wave+eig[numwav]

#potential graph
line=plt.plot(x,V)
plt.setp(line,color='firebrick',linewidth=2)

#plot of the selected level and wave function
plt.axhline(y=eig[numwav],linewidth=2,color='steelblue')

#plot of the points of the wave function
plt.plot(x,wave,"b-",linewidth=2,color='forestgreen')

plt.xlabel('x',size=16)
plt.ylabel('V(x)',size=16)
plt.axis([-4.0,4.0,-5.0,16.0]) #x and y axes range
plt.grid(True)
plt.show()

Answer 1

The reason it looks ugly is that your grid is too finely spaced for plotting with markers. What you can do to add markers to your line is to only add them to every 10 (or whatever) points:

plt.plot(x[::10],wave[::10],"o",color='forestgreen')