How to plot this by gnuplot?

sharonyue · March 11, 2014, 01:56

Hi guys,

I got this force.dat by openfoam function. But I dont know know to plot it.

Code:

0.01	((175.11 -29.1481 -7.68548e-16),(2.75129 -0.0949126 -1.23933e-18),(0 0 0)) ((146.469 879.927 -836.51),(0.476936 13.8252 0.612752),(0 0 0))
0.02	((179.722 -75.9252 -3.0539e-16),(2.34419 -0.060192 -1.06484e-18),(0 0 0)) ((381.524 903.101 -931.303),(0.302465 11.7796 0.402727),(0 0 0))
0.03	((203.615 -106.208 -7.78895e-17),(2.10338 -0.0642538 -7.93942e-19),(0 0 0)) ((533.698 1023.17 -1123.37),(0.322875 10.5695 0.378691),(0 0 0))
0.04	((221.76 -131.418 6.27871e-17),(1.94296 -0.0816487 -8.28315e-19),(0 0 0)) ((660.373 1114.34 -1293.77),(0.410285 9.76335 0.453646),(0 0 0))

I want to set the green part in x axis. and the red one in y axis. how can I get it in terminal?

Thanks

Ruli · March 12, 2014, 05:18

Dear Dongyue,

try this:

1.) Copy the forces.dat for saftey

Code:

cp postProcessing/forces/0/forces.dat postProcessing/forces/0/forces_plot.dat

2.) Replace "((" with "(( "

Code:

sed -i 's/((/(( /g' postProcessing/forces/0/forces_plot.dat

3.) Plot

Code:

gnuplot
plot    "postProcessing/forces/0/forces_plot.dat" u 1:($3) w l t "x-force" axis x1y2

Should work...

Best regards
Julian

sharonyue · March 12, 2014, 08:48

Quote:

Originally Posted by Ruli

Dear Dongyue,

try this:

1.) Copy the forces.dat for saftey

Code:

cp postProcessing/forces/0/forces.dat postProcessing/forces/0/forces_plot.dat

2.) Replace "((" with "(( "

Code:

sed -i 's/((/(( /g' postProcessing/forces/0/forces_plot.dat

3.) Plot

Code:

gnuplot
plot    "postProcessing/forces/0/forces_plot.dat" u 1:($3) w l t "x-force" axis x1y2

Should work...

Best regards
Julian

Awesome! That works, but im a little confused about this :

Code:

plot    "postProcessing/forces/0/forces_plot.dat" u 1:($3) w l t "x-force" axis x1y2

I have tried to change the paramater to another, but failed. So if I wanna the y axis to be the second column. what should I do? Thanks.

Ruli · March 12, 2014, 08:59

Code:

plot    "postProcessing/forces/0/forces_plot.dat" u 1:2 w l t "x-force" axis x1y1

The 1 is the first column for x values, the 2 is the second column for y values.

Bernhard · March 12, 2014, 09:35

Quote:

Originally Posted by Ruli

Dear Dongyue,

try this:

1.) Copy the forces.dat for saftey

Code:

cp postProcessing/forces/0/forces.dat postProcessing/forces/0/forces_plot.dat

2.) Replace "((" with "(( "

Code:

sed -i 's/((/(( /g' postProcessing/forces/0/forces_plot.dat

3.) Plot

Code:

gnuplot
plot    "postProcessing/forces/0/forces_plot.dat" u 1:($3) w l t "x-force" axis x1y2

Should work...

Best regards
Julian

You might want to use "sed -i.bak", which gives you the back-up file right away.

If you want to plot multiple columns, there is no need to retype the filename, i.e.

Code:

plot "filename" using 1:2, "" using 1:5, "" using 1:8

will work for you, probably.

sharonyue · March 12, 2014, 09:42

Code:

plot "w.dat" using 1:3 w l,"" using 1:11 w l, "" using 1:4 w l

Thank you guys! this would be more clear.

sharonyue · March 20, 2014, 02:24

Code:

0.01	((122.847 3.11355 1.99776e-16),(2.35502 0.0580908 -6.78944e-19),(0 0 0)) ((-0.0778387 3.07116 -647.967),(-0.00145227 0.0588756 -3.40765),(0 0 0))

Right now I wanna add 122.847 with 2.35502. How can I get this value in terminal?

Solved:

Code:

awk '{print $2}' forces > t

extract the second column.

March 12, 2014, 05:18		#2
Ruli Member Julian Langowski Join Date: May 2011 Location: Bremen, Germany Posts: 91 Rep Power: 14	Dear Dongyue, try this: 1.) Copy the forces.dat for saftey Code: cp postProcessing/forces/0/forces.dat postProcessing/forces/0/forces_plot.dat 2.) Replace "((" with "(( " Code: sed -i 's/((/(( /g' postProcessing/forces/0/forces_plot.dat 3.) Plot Code: gnuplot plot "postProcessing/forces/0/forces_plot.dat" u 1:($3) w l t "x-force" axis x1y2 Should work... Best regards Julian panda, sharonyue and Richal Sun like this. __________________ πάντα ῥεῖ - Heraclitus

March 12, 2014, 08:59		#4
Ruli Member Julian Langowski Join Date: May 2011 Location: Bremen, Germany Posts: 91 Rep Power: 14	Code: plot "postProcessing/forces/0/forces_plot.dat" u 1:2 w l t "x-force" axis x1y1 The 1 is the first column for x values, the 2 is the second column for y values. sharonyue likes this. __________________ πάντα ῥεῖ - Heraclitus

March 12, 2014, 09:42		#6
sharonyue Senior Member Dongyue Li Join Date: Jun 2012 Location: Beijing, China Posts: 838 Rep Power: 17	Code: plot "w.dat" using 1:3 w l,"" using 1:11 w l, "" using 1:4 w l Thank you guys! this would be more clear.

March 20, 2014, 02:24		#7
sharonyue Senior Member Dongyue Li Join Date: Jun 2012 Location: Beijing, China Posts: 838 Rep Power: 17	Code: 0.01 ((122.847 3.11355 1.99776e-16),(2.35502 0.0580908 -6.78944e-19),(0 0 0)) ((-0.0778387 3.07116 -647.967),(-0.00145227 0.0588756 -3.40765),(0 0 0)) Right now I wanna add 122.847 with 2.35502. How can I get this value in terminal? Solved: Code: awk '{print $2}' forces > t extract the second column.

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