import pylab as plt
import numpy as np
from matplotlib.ticker import LogLocator

plt.rc('text', usetex=True)
f,ax=plt.subplots(figsize=(10,8))
plt.xscale('log')
plt.yscale('log')
plt.ylim([1e26,1e29])
plt.xlim([20,1e10])
plt.xlabel(r'x',fontsize=22)
plt.ylabel(r'y',fontsize=22)
plt.tick_params(axis='both', which='major', labelsize=22,length=9,direction='in')
plt.tick_params(axis='both', which='minor', labelsize=22,length=5,direction='in')
ax.yaxis.set_tick_params(right='on',which='both')
ax.xaxis.set_tick_params(top='on',which='both')

# manipulate x-axis ticks and labels
ax.xaxis.set_major_locator(LogLocator(numticks=15)) #(1)
ax.xaxis.set_minor_locator(LogLocator(numticks=15,subs=np.arange(2,10))) #(2)
for label in ax.xaxis.get_ticklabels()[::2]:
    label.set_visible(False) #(3)

plt.savefig('example.pdf',bbox_inches='tight')