Script for NBLUG talk on gnuplot

On a thumbdrive
    slides
    script
    all data files for talk

Take
    Printed copy of script and slides
    Pad of paper
    Ruler
    Gnuplot in action book
    Pointer
    Computer, keyboard, mouse, pad, power cords (main box and monitor)
        monitor cable, keyboard cable, mouse cable, power strip
    Acer monitor

Test at O'Reilly
    KB works, mouse works, monitor works
    Projector hooks up to my computer and works
    Have Internet connection?
    MAKE SURE LINES AND TEXT OF GRAPHS SHOW UP WELL ON SCREEN!

Setup before the talk

    Open a gedit window and open these files in it
        Following files in ~/roger/associations/NBLUG/gnuplotTalk
            script.txt
            prices

    In the File Browser, navigate to ~/roger/associations/NBLUG/gnuplotTalk
    Double click on NBLUGTalkGnuplot.ppt

    Navigate to ~/OpenSourceCode/gnuplot/doc
    Double click on GnuplotinAction.pdf
    Go to page 316 (list of math functions)

    Open a terminal window
    cd ~/roger/associations/NBLUG/gnuplotTalk

    gnuplot
    cd "/home/rhouse/roger/associations/NBLUG/gnuplotTalk"
    plot sin(x)

    Place terminal window below and graphics window above

    load "scripts/set_line_styles.gp"
    plot sin(x)     (see if the lines are thick enough)
    plot "prices"   (see if the point sizes are okay)

    exit  (graphics window disappears)
    clear (terminal window empty except for prompt)

    Bring up first slide, full screen, and leave it up until talk starts

Preamble

    Kyle keeps looking for smaller and smaller computers;
    I'm going the other way; my next machine is going to be a mainframe

Title Slide

    Go over title slide
    The talk will be a combination of slides and demo 
        (mostly demo so I don't have to prepare so many slides)
    Many of the demos have been shamelessly pulled right off the Internet
        (Thanks to the many people who have contributed.)
    I'm not an expert, so bear with my confusion

    Show the book Gnuplot in Action

    Bring up the terminal window (already positioned as we want)
    gnuplot

    Commands are typed in the terminal window

    plot sin(x)

    Adjust the graphics window size
    Plotting happens in the graphics window

    plot sin(x) (again to show how the window fills)

    "Pay no attention to the man behing the curtain"
    load "scripts/set_line_styles.gp"

    plot sin(x) (again to show how the line thickness has changed)

Tips when gnuplot has just been installed

    set dummy x
    set xrange [-10:10]
    set yrange [-1:1]

Examples of capabilities:

    plot sin(x), atan(x)
    (notice automatic colors)

    plot [-15:15] [-2:2] sin(x), atan(x)
    (notice x-range and y-range)

    plot [-10:10] [-3:3] sin(x), atan(x), cos(atan(x))
    (notice colors again, and more complex expression)

    Here is a series of various plots, to show capabilities

    plot [-pi/2:pi] [-1:1] cos(x),-(sin(x) > sin(x+1) ? sin(x) : sin(x+1))
    (note the ternary operator)

    plot [-5*pi:5*pi] [-5:5] real(tan(x)/atan(x)), 1/x
    (note the real(z) function)

    plot [-10:10] [-1:4.5] real(sin(x)**besj0(x))
    (note the Bessel function)

Functions available
    Show p316 of the book pdf:  Math (and other functions) available

How to increase the resolution
    plot [-30:20] [-2:2] sin(x*20)*atan(x)
    set samples 800, 800
    replot
    set samples 100, 100

Three plot commands
    Notice the use of replot
    Show slide with plot, splot, replot

Plot styles
    plot sin(x)
    plot sin(x) with points
    plot sin(x) with linespoints
    plot sin(x) with dots  (single pixels)
    plot sin(x) with lines
    plot sin(x) with impulses

    plot [-30:20] [-2.5:1.5] besj0(x)*1.2 with impulses, (x**besj0(x))-2.5

Plotting data

    Show slide with the two things we can plot

    plot "prices"
    (look at the x-axis and y-axis and the plotted points)

    Look at prices file with gedit
        1st column:  Years (x-axis)
        2nd column:  Stock prices (y-axis)
    What about the other two columns?

    plot "prices" using 1:3
    (notice selection of what is x and what is y)

    plot "prices" using 1:4

    plot "prices", "prices" using 1:3, "prices" using 1:4
    (notice we get three plots, all different colors, all with diff. symbols)

    plot "prices", "prices" using 1:3, "prices" using 1:4 with lines
    (note that default for data files is "with points", for functions is
    "with lines", but both can be overridden)

    plot "prices", "prices" using 1:3, "prices" using 1:4, tan(x)
    (we can mix plots of data and functions)

Parametric plotting

    Circle slide 1:  "What does this represent?"
    Circle slide 2:  "How to plot a circle?"

    plot [-1.1:1.1] [-1.1:1.1] sqrt(1 - x**2),-sqrt(1 - x**2)
    set size square

    This is definitely NOT the way to go 

    Circle slide 2:  "Better way to plot a circle"

    set parametric
    plot [0:2*pi] cos(t), sin(t)

  Another example
    load "./scripts/spiral.gp"

    unset parametric
    set size nosquare

3d

    f(x,y) = exp(-(x**2 + y**2)) * cos(x/4) * sin(y) * cos(2*(x**2+y**2))
    (we have defined a function)
    show functions

    splot [-2:2][-2:2] f(x,y)
    (doesn't look that good)

    We need to increase the resolution
    show isosamples
    set isosamples 30, 30

    Looks better if we do this:
    set hidden3d

    More commands
    set view 77,77
    set xyplane 0
    set pm3d

  Two tori example
    unset pm3d
    load "./scripts/two_tori.gp"

  False color example
    unset parametric
    load "./scripts/falsecolor.gp"

    load "./scripts/squaresymmetry.gp"

    unset pm3d

Terminals

    show terminal
    help wxt
    set terminal
    (58 terminals in the list)

  How to output to a different terminal
    Display export_jpeg.gp to show what we're about to do
    set title
    plot sin(x)
    call "./scripts/export_jpeg.gp" "sin.jpg"

Test command

Wrap up

    Look at 99bottles.gp
    load "./scripts/99bottles.gp"

Last couple of slides