import numpy as np
import matplotlib.pyplot as plt

f=open('shallow.dat','rb')

(m,n)=np.fromfile(f,'i8',2)
(dx,h)=np.fromfile(f,'d',2)
L=dx*m

x=(np.arange(m)+0.5)*dx

for i in range(n+1):
    var = np.fromfile(f,'d',(m+1)*2)
    var = var.reshape((m+1,2),order='F')    
    t=h*i
    plt.cla()
    plt.ylim(-0.01, 0.01)
    plt.xlim(0, L)        
    plt.plot(x,var[:m,0])
    plt.ylabel(r'$\eta$')
    plt.xlabel(r'$x$')
    plt.title(r'$t=$'+'{:.5f}'.format(t),loc='right',fontsize=10)    
    plt.pause(0.01)

f.close()