Question

Gnuplot gives me the following picture with an odd disjoint in the second graph, whose origin I cannot determine. I’ve included the data below, in which the x-values are monotonically increasing, which should rule out the possibility of such a disjoint. Any help appreciated!

Generated from the following script:

set size 0.8,0.4
set lmargin 1
set terminal png
set output "test.png"
set multiplot
set origin 0.1,0.1
set xtics 5
set xrange[0:25]
set xlabel "Year"
plot "./g1" u ($1+1):2 w lines t "4 years"
set xlabel ""
set origin 0.1,0.5
set xtics format ""
set x2tics 5
plot "./g2" u ($1+1):2 w lines t "5 years"
unset multiplot

Data for g1 is:

0.000000    1.000000
1.000000    3.000000
2.000000    9.000000
3.000000    27.000000
4.000000    0.809131
5.000000    2.427394
6.000000    7.282183
7.000000    21.846549
8.000000    0.654694
9.000000    1.964081
10.000000   5.892243
11.000000   8.935199
12.000000   0.529733
13.000000   1.589200
14.000000   3.983240
15.000000   2.509780
16.000000   0.428624
17.000000   1.233139
18.000000   1.951804
19.000000   0.595792
20.000000   0.343980
21.000000   0.809600
22.000000   0.729229
23.000000   0.171423
24.000000   0.258384
25.000000   0.426250

Data for g2 is:

0.000000        1.000000
1.000000        3.000000
2.000000        9.000000
3.000000        27.000000
4.000000        81.000000
5.000000        2.427394
6.000000        7.282183
7.000000        21.846549
8.000000        65.539647
9.000000        196.618942
10.000000       5.892243
11.000000       17.676730
12.000000       53.030190
13.000000       159.090569
14.000000       241.250367
15.000000       14.302798
16.000000       42.908394
17.000000       128.725182
18.000000       322.642448
19.000000       203.292210
20.000000       34.718531
21.000000       104.155593
22.000000       299.652772
23.000000       474.288428
24.000000       144.777335
25.000000       84.275565

Answer 1

That’s strange. On my system (ubuntu 11.10 64bit) I don’t see the problem you have:

$ gnuplot --version
gnuplot 4.4 patchlevel 3

$ gnuplot < a.gnuplot  # a.gnuplot is your script, unmodified

And it produces this:

If I were you I’d check:

1. gnuplot version
2. The input files – in vim use set list to see if there’s any rampant characters hidden