gnuplot on ruby

Discussion in 'Ruby' started by soxinbox, Oct 21, 2005.

  1. soxinbox

    soxinbox Guest

    I installed gnuplot gem, and I am getting some syntax errors when I try to
    run the samples on the projects web page.
    c:/programs/ruby/lib/ruby/gems/1.8/gems/gnuplot-2.1/lib/gnuplot.rb:20:in
    `popen': No such file or directory - which gnuplot (Errno::ENOENT)
    from
    c:/programs/ruby/lib/ruby/gems/1.8/gems/gnuplot-2.1/lib/gnuplot.rb:20:in
    `open'
    from test.rb:2
    my test code is copied directly from the gnuplot ruby project web page
    except the added require 'gnuplot' which is not mentioned in the example. I
    think I am missing something simple here.

    require 'gnuplot'
    Gnuplot.open do |gp|
    Gnuplot::plot.new( gp ) do |plot|

    plot.title "Array Plot Example"
    plot.ylabel "x"
    plot.xlabel "x^2"

    x = (0..50).collect { |v| v.to_f }
    y = x.collect { |v| v ** 2 }

    plot.data << Gnuplot::DataSet.new( [x, y] ) do |ds|
    ds.with = "linespoints"
    ds.notitle
    end
    end
    end

    any help is appreciated.
     
    soxinbox, Oct 21, 2005
    #1
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  2. soxinbox

    Ara.T.Howard Guest

    it looks like the code must do

    IO::popen `which gnuplot`

    so either

    - gnuplot is not on your system

    - gnuplot is not in your path

    can you verify both of these? from the shell do

    ~:> which -a gnuplot


    -a
    --
    ===============================================================================
    | email :: ara [dot] t [dot] howard [at] noaa [dot] gov
    | phone :: 303.497.6469
    | anything that contradicts experience and logic should be abandoned.
    | -- h.h. the 14th dalai lama
    ===============================================================================
     
    Ara.T.Howard, Oct 21, 2005
    #2
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  3. Ara is completely correct with his diagnosis. You have two choices,
    either ensure that gnuplot is in your path or hardcode the path in the
    gnuplot.rb file. I've struggled for a number of years on how to
    improvie this but haven't been able to come up with something better
    that satisfies my sense of right and wrong. Suggestions would be
    appreciated.

    Gordon
     
    gordon.j.miller, Oct 21, 2005
    #3
  4. soxinbox

    soxinbox Guest

    Aha! I see it now. The problem isn't that gnuplot isn't in the path, but
    that 'which' is not a standard command on windows XP.
    I guess not many people have tried running this under windows.
     
    soxinbox, Oct 21, 2005
    #4
  5. soxinbox

    soxinbox Guest

    gordon, It looks like the gnuplot executable on windows needs to be
    pgnuplot.exe. Might I suggest that when on windows you set cmd = "pgnuplot"
    and assume it is in the path. I don't know the ruby way to check for
    platform, perhaps ENV["OS"].downcase.include?("win") or some such hack.
     
    soxinbox, Oct 21, 2005
    #5
  6. soxinbox

    Ara.T.Howard Guest

    maybe somthing like (un-tested):

    def which bin
    path = ENV['PATH'] # || ENV['WHAT_EVER_WINDOWS_PATH_VAR_IS']
    path.split(File::pATH_SEPARATOR).each do |dir|
    candidate = File::join dir, bin
    return candidate if File::executable? candidate
    end
    return nil
    end

    gnuplot = ENV['RB_GNUPLOT'] || 'gnuplot'

    gnuplot = which gnuplot or raise 'gnuplot is not in your path'

    or, if windows isn't a concern

    gnuplot = `which gnuplot`

    raise 'gnuplot not in your path' unless $? == 0

    IO::popen gnuplot


    thanks for the good work on gnuplot btw - i've used in many times.

    cheers.

    -a
    --
    ===============================================================================
    | email :: ara [dot] t [dot] howard [at] noaa [dot] gov
    | phone :: 303.497.6469
    | anything that contradicts experience and logic should be abandoned.
    | -- h.h. the 14th dalai lama
    ===============================================================================
     
    Ara.T.Howard, Oct 21, 2005
    #6
  7. soxinbox

    soxinbox Guest

    You will have to add something to change the search to look for pgnuplot.exe
    as there is no gnuplot.exe on windows. I have just started using this, but I
    agree it looks cool. I hope to use it to output some technical graphs.
    Thanks to those that created gnuplot and the ruby adaptation layer.

     
    soxinbox, Oct 22, 2005
    #7
  8. soxinbox

    Edwin Guest

    While we are on the topic off rgnuplot, does anybody know if it is =20
    possible to still "turn" 3d graphs when called from ruby. If I make a =20
    graph directly in gnuplot I can spin it around with the mouse to look at =
    =20
    it from different sides. With rgnuplot that doesn't seem possible.

    (This is on linux)

    Edwin

    --=20
    Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
     
    Edwin, Oct 22, 2005
    #8
  9. Another FYI, I have found that under windows, the gnuplot from cygwin
    is actually better than the native pgnuplot, for handling piped input
    (and cygwin will also fix the missing which issue).

    pth
     
    Patrick Hurley, Oct 22, 2005
    #9
  10. I'm not too familiar with the interactive gnuplot capabilities (I
    stepped out of gnuplot development around this time and don't really
    care about the interactive part). When the plot window is up it is
    being executed from within gnuplot so it should respond the exact same
    as it would interactively.
     
    gordon.j.miller, Oct 24, 2005
    #10
  11. Sorry for the delay in replying, I only participate in the digest mode.

    I'll put something like Ara mentioned into the codebase and put a new
    release out within the next week. Thanks for the good suggestions.

    Gordon
     
    gordon.j.miller, Oct 24, 2005
    #11
  12. soxinbox

    stevereinke Guest

    Am Samstag, 22. Oktober 2005 11:49:32 UTC+2 schrieb Edwin:
    Hi Edwin,

    can you please tell me how to generate 3d graphs using rgnuplot?

    I'm trying this for a few days.

    Thanks, steve
     
    stevereinke, Dec 18, 2012
    #12
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