Assume that I have some array of data (a vector to be specific).
Can I plot it element by element sequentially using Gnuplot such that it seems as if it is a real life signal that is being traced through a monitor?
I know that I can write the whole data into a text file using Common Lisp, then using gnuplot I can plot it in a batch format. What I require is that I want to put a point on my plot as data comes sequentially.
Data will probably be generated inside a loop, thus you may consider x-axis as the integer valued discrete-time axis. So in the loop if the first element of the array is generated as 5, I would like to put a point on my plot to (0,5). Then if the second element is generated as 3, I would like to put another point on my plot to (1,7) (preserving the old data point). So as I iterate through the loop, I plot the data sequentially.
I am using emacs and Common Lisp for my purposes and I want to plot this data staying within these tools. If there are any other options other than Gnuplot, I would like to hear them.
If this is not easily possible, it would be cool, if I can run a Gnuplot command file by some Common Lisp command.
edit:
Following advices people gave under this thread, I wrote a code using cgn which uses ltk.
Right now I open two x11 windows at pre-specified positions on my screen and I enter the loop. In loop each time I open a stream and write the data (sine and cosine waves of 0.25 Hz sampled at 20 Hz) to the text file trial.txt with the :if-exists :append option and close the stream. Then at each iteration I plot the whole data using the gnuplot through the format-gnuplot command. This code gives me two windows of pre-specified x and y ranges and then one can watch the evolutions of aforementioned sine and cosine waves in the windows.
As I have stated before I don’t have strong programming background (I am an electrical engineer who somehow ended using common lisp) and I am pretty sure that my code is non-optimal and unelegant. If you guys have some further advices, corrections etc. I would really like to hear them. The code is here:
(setf filename "trial.txt")
(setf path (make-pathname :name filename))
(setf str (open path :direction :output :if-exists :supersede :if-does-not-exist :create))
(format str "~,4F ~,4F" -1 -1)
(close str)
;start gnuplot process
(start-gnuplot "/Applications/Gnuplot.app/Contents/Resources/bin/gnuplot")
;set 2 x11 windows with the following properties
(format-gnuplot "cd ~S" "Users/yberol/Desktop/lispbox/code")
(format-gnuplot "set terminal x11 0 position 0,0")
(format-gnuplot "set xrange [0:10]")
(format-gnuplot "set yrange [-1:1]")
(format-gnuplot "unset key")
(format-gnuplot "set grid")
(format-gnuplot "plot ~S using 1" filename)
(format-gnuplot "set terminal x11 1 position 800,0")
(format-gnuplot "plot ~S using 2" filename)
;write data into text
(loop :for i :from 0 :to 10 :by (/ 1 20) :do
(setf str (open path :direction :output :if-exists :append :if-does-not-exist :create))
(format str "~,4F ~,4F ~,4F ~%" i (sin (* 2 pi (/ 5 20) i)) (cos (* 2 pi (/ 5 20) i)))
(close str)
(format-gnuplot "set terminal x11 0")
(format-gnuplot "plot ~S using 1:2 with lines" filename)
(format-gnuplot "set terminal x11 1")
(format-gnuplot "plot ~S using 1:3 with lines" filename)
(sleep 0.1))
(close-gnuplot)
Thank you very much.
cgn is a working Common Lisp solution for interfacing with gnuplot, which uses LTK