Plotting two .txt files in the same figure using Python
<p>I am trying to plot two .txt files in the same figure. I am using a simple Python script for that.</p>

<pre><code>import sys
import os
import numpy
import matplotlib.pyplot as plt
from pylab import *

trap_error = 'trap_error.txt'

N , error = numpy.loadtxt(trap_error, unpack =True)

monte_error = 'monte_carlo_error.txt'

points, Integral, error = numpy.loadtxt(monte_error, unpack =True)

plt.loglog(N,error, 'o')

plt.loglog(points,error, 's')


plt.xlabel('Number of equally spaced points N')
plt.ylabel('error')
plt.legend(['trapezoid rule error', 'monte carlo error'], loc = 'upper right')
plt.title('Comparison of error in Trapezoid rule and Monte Carlo rule of Numerical integration')
plt.show()
</code></pre>

<p>The output figure only shows the monte carlo data, but no trace of trapezoid data. The order of magnitude of these two data file is almost same, so I do not understand why I cannot see the other data in the same figure. I am also sharing the datafiles for convenience.</p>

<pre><code>  #points    Integral    error      # monte_carlo_error.txt   
   2          1.400697    0.170100
   4          1.415539    0.155258
   8          1.394789    0.176008
   16         1.444948    0.125848
   32         1.501825    0.068971
   64         1.577106    0.006309
   128        1.558217    0.012580
   256        1.563389    0.007407
   512        1.570139    0.000657
   1024       1.576300    0.005504
   2048       1.585733    0.014937
   4096       1.577355    0.006558
   8192       1.577293    0.006497
   16384      1.575404    0.004607
   32768      1.572333    0.001536
   65536      1.571028    0.000232
   131072     1.570317    0.000479
   262144     1.570318    0.000478
   524288     1.570867    0.000070
   1048576    1.571311    0.000515

#N           error         #trap_error.txt
2            0.629204
4            0.472341
8            0.243747
16           0.123551
32           0.062155
64           0.031166
128          0.015604
256          0.007807
512          0.003905
1024         0.001953
2048         0.000977
4096         0.000487
8192         0.000244
16384        0.000124
32768        0.000064
65536        0.000040
131072       0.000044
262144       0.000087
524288       0.000018
1048576      0.000615
</code></pre>

<p>You rewrote error from trap_error.txt file. Use the below code to fix your issue</p>

<pre><code>trap_error = 'trap_error.txt'
N , error1 = numpy.loadtxt(trap_error, unpack =True)
monte_error = 'monte_carlo_error.txt'
points, Integral, error2 = numpy.loadtxt(monte_error, unpack =True)
plt.loglog(N,error1, 'o')
plt.loglog(points,error2, 's')
</code></pre>

python matplotlib