How to skip COLUMN while drawing graph in gnuplot

I am planning to draw a 2D plot using gnuplot .

But in this case I want to skip first column of my data.txt file .

Background of this question is ,I am having two inputs for given output . But I want to draw the graph using one input only ..as I Am using input pattern as FIXED_CONSTANT and random data for ease of drawing .

But How I can skip the first column in my given code in run.gpl file where the FIXED_CONSTANT is coming as input. I want to use second column as input for drawing my graph..

Can you please suggest me the changes in given code .

my run.gpl is :

### three curves in one plot with two y-axes
reset session
set terminal png size 1024,768 font ",12"
set output "graph.png"
set xlabel "Input"

set ylabel "output"
set ytics nomirror

set y2label "Error"
set y2tics nomirror

set grid
set key

plot 'data.txt' u 1:3 w p axes x1y1 ti "Ref output" lc rgb "red" , \
     '' u 1:4 w p axes x1y1 ti "OPT output" lc rgb "green" , \
     '' u 1:5 w p axes x1y2 ti "Error between Ref and OPT output" lc rgb "blue"     
set output
### end of code

data.txt file :

|--INPUT0--|--INPUT1--|--REF_OUT--|--OPT_OUT--|--ERROR--|

  10.000000000000000   36.122192382812500    0.270114153623581    0.270074307918549    0.000039845705032
  10.000000000000000   38.702346801757812    0.252882927656174    0.252852171659470    0.000030755996704
  10.000000000000000   41.282516479492188    0.237678512930870    0.237655565142632    0.000022947788239
  10.000000000000000   43.862670898437500    0.224169462919235    0.224153116345406    0.000016346573830
  10.000000000000000   46.442825317382812    0.212091386318207    0.212080582976341    0.000010803341866
  10.000000000000000   49.022979736328125    0.201231494545937    0.201225265860558    0.000006228685379
  10.000000000000000   51.603134155273438    0.191416561603546    0.191414132714272    0.000002428889275
  10.000000000000000   54.183303833007812    0.182504311203957    0.182505041360855   -0.000000730156898
  10.000000000000000   56.763458251953125    0.174377039074898    0.174380362033844   -0.000003322958946
  10.000000000000000   59.343612670898438    0.166936323046684    0.166941791772842   -0.000005468726158
  10.000000000000000   61.923767089843750    0.160099431872368    0.160106644034386   -0.000007212162018
  10.000000000000000   64.503936767578125    0.153796255588531    0.153804913163185   -0.000008657574654
  10.000000000000000   67.084091186523438    0.147967159748077    0.147977009415627   -0.000009849667549
  10.000000000000000   69.664245605468750    0.142560914158821    0.142571732401848   -0.000010818243027
  10.000000000000000   72.244400024414062    0.137533426284790    0.137545034289360   -0.000011608004570
  10.000000000000000   74.824554443359375    0.132846444845200    0.132858693599701   -0.000012248754501
  10.000000000000000   77.404708862304688    0.128466725349426    0.128479465842247   -0.000012740492821
  10.000000000000000   79.984878540039062    0.124365106225014    0.124378263950348   -0.000013157725334
  10.000000000000000   82.565032958984375    0.120516106486320    0.120529577136040   -0.000013470649719
  10.000000000000000   85.145187377929688    0.116897158324718    0.116910874843597   -0.000013716518879
  10.000000000000000   87.725357055664062    0.113488301634789    0.113502189517021   -0.000013887882233
  10.000000000000000   90.305511474609375    0.110271871089935    0.110285893082619   -0.000014021992683
  10.000000000000000   92.885665893554688    0.107232064008713    0.107246160507202   -0.000014096498489
  10.000000000000000   95.465820312500000    0.104354768991470    0.104368910193443   -0.000014141201973
  10.000000000000000   98.045974731445312    0.101627349853516    0.101641491055489   -0.000014141201973
  10.000000000000000  100.626129150390625    0.099038407206535    0.099052540957928   -0.000014133751392
  10.000000000000000  103.206283569335938    0.096577703952789    0.096591800451279   -0.000014096498489
  10.000000000000000  105.786453247070312    0.094235941767693    0.094249986112118   -0.000014044344425
  10.000000000000000  108.366607666015625    0.092004776000977    0.092018745839596   -0.000013969838619
  10.000000000000000  110.946762084960938    0.089876532554626    0.089890420436859   -0.000013887882233

And also if possible can you suggest me in your answer for plotting the 3D graph using gnuplot for my given scnerio by considering my current run.gpl. for 3D Graph, I can change my first column FIXED_CONSTANT value to random generated also .

1 answer

  • answered 2020-01-17 13:15 Vinicius Placco

    If I understood the question correctly, you would only have to change the u 1:3 to u 2:3 and so on:

    plot 'data.txt' u 2:3 w p axes x1y1 ti "Ref output" lc rgb "red" , \
     '' u 2:4 w p axes x1y1 ti "OPT output" lc rgb "green" , \
     '' u 2:5 w p axes x1y2 ti "Error between Ref and OPT output" lc rgb "blue"
    

    Was that what you're looking for? For a simple 3D plot you could try:

    splot 'data.txt' u 2:3:4