Gnuplot from array
in [Fortran]
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From: Craig Powers on 11 May 2010 17:43 Allamarein wrote: > On 11 Mag, 23:20, Craig Powers <craig.pow...(a)invalid.invalid> wrote: >> Allamarein wrote: >>> On 11 Mag, 23:01, Craig Powers <craig.pow...(a)invalid.invalid> wrote: >>>> Allamarein wrote: >>>>> Let's suppose I produced 2 arrays >>>>> REAL, DIMENSION (0:MAX_SIZE) :: T,Y >>>>> where max_size is an appropriate integer. >>>>> May you suggest a code that create a GRAPH.PLT to see a T (x axis)- >>>>> Y(y axis) plot by gnuplot ? >>>>> I would export T and Y in a single file called DATA.DAT too. >>>>> May you proposed codes? >>>> OPEN(UNIT=out_unit, FILE='DATA.DAT', STATUS='NEW') >>>> DO I = 0, MAX_SIZE >>>> WRITE(out_unit,*) T(I), Y(I) >>>> ENDDO >>>> Assumes appropriate declarations for I and out_unit. 'NEW' may not be >>>> the best status, but it's an appropriate approximation. List-directed >>>> format may not end up being what you want, but it's a nice easy starting >>>> point. >>>> I'm not familiar with gnuplot, so I'll leave the manipulation of the >>>> data file as an exercise to you or other follow-ups. >>> I'm a newbie. >>> What means 'Assumes appropriate declarations for I and out_unit' ? >>> Sorry, be patient.... >> INTEGER :: I >> INTEGER, PARAMETER :: out_unit = 20 >> >> out_unit doesn't have to be 20, but it should probably be greater than 9 >> (single-digit unit numbers risk colliding into compiler extensions that >> pre-connect units with special destinations, like stderr, stdin, stdout, >> and so on). > > status="new" gets error if I have just the file (of course). > Shall I delete that before re-run? > How can I modify my code? Read your favorite Fortran reference for alternative statuses. My preferred online reference is: http://h21007.www2.hp.com/portal/download/files/unprot/fortran/docs/lrm/dflrm.htm It only goes up to Fortran 95, but there are other places I can go if I need newer stuff.
From: e p chandler on 11 May 2010 19:55 "Allamarein" <matteo.diplomacy(a)gmail.com> wrote in message news:1d0dbd64-079b-4846-9e47-6e11bdc4d743(a)p2g2000yqh.googlegroups.com... > Let's suppose I produced 2 arrays > > REAL, DIMENSION (0:MAX_SIZE) :: T,Y > > where max_size is an appropriate integer. > May you suggest a code that create a GRAPH.PLT to see a T (x axis)- > Y(y axis) plot by gnuplot ? > I would export T and Y in a single file called DATA.DAT too. > > May you proposed codes? FIRST you have to know the data format required by gnuplot. see http://www.duke.edu/~hpgavin/gnuplot.html for a tutorial. Next you write a Fortran program that writes the contents of the array to your data file. I suspect that you will be able to use list directed formatting to write your output file instead of having to line up your data in columns but YMMV. Here's an outline open the output file for index_var = its_min to its_max write to the output file T(index_var), Y(index_var) close the output file You can even automate the process so that GnuPlot takes its commands from a script in a command file. - Elliot
From: rudra on 12 May 2010 07:56 On May 12, 2:42 am, Allamarein <matteo.diplom...(a)gmail.com> wrote: > status="new" gets error if I have just the file (of course). > Shall I delete that before re-run? > How can I modify my code? status='NEW' means you are going to have a new file, and gives error if the file already exists. may be you can try status='replace' or just delete the file before a fresh run.
From: ndl_91 on 14 May 2010 08:41
On 11 mai, 22:46, Allamarein <matteo.diplom...(a)gmail.com> wrote: > Let's suppose I produced 2 arrays > > REAL, DIMENSION (0:MAX_SIZE) :: T,Y > > where max_size is an appropriate integer. > May you suggest a code that create a GRAPH.PLT to see a T (x axis)- > Y(y axis) plot by gnuplot ? > I would export T and Y in a single file called DATA.DAT too. > > May you proposed codes? Hi. There are several ways for drawing a curve from a code... The simplest, you mentionned, is to write it outside the code but you could imagine invoking gnuplot directly from your code by using a UNIX pipe or a FIFO file. It allows you to produce real time vizualisation. Tell me if your intersted in more details. Anyway, Here is what you asked for : >cat test.f90 program test implicit none integer, parameter :: MAX_SIZE=10 integer :: I_unit, I real(kind=8), dimension(0:MAX_SIZE) :: T, Y ! ! Create your DATA T(:)=(/ (real(I,kind=8), I=0,MAX_SIZE) /) Y(:)=T(:)**2 ! ! Write It to a file I_unit=10 open(unit=I_unit,file="DATA.DAT",status="unknown",form="formatted") do I=0,MAX_SIZE write(I_unit,'(E15.7,1X,E15.7)') T(I),Y(I) enddo close(I_unit) end program test >cat GRAPH.PLT reset set title "My pretty graph" set xl "t (s)" set yl "Y (m)" set key top left set key Left reverse set grid plot "DATA.DAT" u 1:2 w lp lw 2 title "My curve" set term push set term postscript solid enhanced color colortext set output "DATA.eps" rep set o set term pop Then you can call this script from gnuplot (load "GRAPH.PLT") or simply by invoking gnuplot -persist GRAPH.PLT Hope it helps, NL |