TPUG - Toronto PET Users Group/TPUG Users Group CD/TPUG Users Group CD.iso/CRS/crs19.d81/simman.arc/MANDEL2.TXT

Text File | 2009-10-10 | 8KB | 199 lines

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         The manual method gives you the most control over the colorizing
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    process.  You can specify up to 20 manual cutoff points.  In this
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    manner you accentuate the details of most interest, and lose cluttered
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    areas that distract from the image.
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         Once you have generated an image you like, MANDELPAINT will save
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    it for you as a 32-block picture file on drive 8.  The file naming
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    conventions were mentioned earlier.  If you used the auto-mode the
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    entire filename will be automatically created.  The extension will
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    correspond to the value you used for colorizing.  If you use the manual
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    method, you can specify your own extension name.  Anything you like,
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    just dont make it overly long, you need room for the root name and the
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    "y" or "n" at the end.  The extension helps to distinguish between
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    multiple versions of the same area of the set.  For example, you might
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    have "jazz.2000.y" and "jazz.3000.y" as two different interpretations
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    of "jazz.dat" on drive 9.  If you used manual cutoffs, you might have
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    "jazz.simple.y" and "jazz.complex.y".  All these examples would contain
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    the mandelbrot set, as represented by the trailing "y".
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         Once you have seen an interesting area, it is almost irresistable
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    to explore it further.  You will want to "zoom" in on parts of the
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    screen to see them in more detail.  That is where MAGNIBROT comes in.
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    MAGNIBROT
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         MAGNIBROT makes zooming in on areas of the set, a breeze.
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         Load and run MAGNIBROT (with SIMON'S BASIC).  Tell it which
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    graphics image you would like to view.  Use the root name.  Magnibrot
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    will search drive 9 for the parameter file, which it will use to
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    calculate new parameters when you "zoom".
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         The image will be displayed.  In the upper left hand area of the
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    screen, you will see a small flashing box.  This is the magnification
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    window.  Use it to pick a region to magnify.  The cursor control keys
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    will move the box around.  The ">" and <" keys will change the size of
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    the box.  The box will move fastest when at its smallest size, so move
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    it to the center of the region you wish to magnify, then expand it.
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    When you have the area selected, press "m" to magnify.  You will be
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    asked the number of iterations to be used in calculating the new file.
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    The other parametes will be computed for you.  make sure there is room
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    on drive 9 for the next data file.  If the disk already has 2 data
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    files on it, you should load a new blank disk to hold the parameters
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    for the next run.
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         You will also be given the "magnification" level of the new image
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    in "standard m-brots".  This is just a means of comparison.  The image
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    named "mama.1200.y" is considered the standard size.
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         The maximum theoretical effective magnification of this system is
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    18,000,000 "standard m-brots".  Generally, higher magnifications
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    require higher iteration values, and take longer to run.
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         You can save copies of the screen images from MAGNIBROT.  That is,
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    you can save the picture with the magnification window imbedded in it.
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    This helps when viewing a magnification sequence, as it shows where











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    each successive image will be coming from.  These will also be 32-block
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    files.  You can name them anything you wish, though you might want to
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    keep the "y" "n" convention at the end.
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    THE BASIC PROGRAMS
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         Auto-seq and Colours are two basic programs used to display images
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    of the set.  We've already gone over Colours.  Auto-seq lets you make
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    slide shows out of a sequence of mandelbrot images.  You can show
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    images of sucessively greater magnification, or the effects of
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    successively narrow color regions on the same slide.  To change
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    Auto-seq, you have to edit the basic program.  If you are familiar with
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    basic, use the sample program as your template.  Simply change the
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    lines that load in the images.  To add more lines, just keep increasing
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    the values for "a".  These basic programs use SIMON'S BASIC for
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    graphics control.
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    HINTS AND TIPS
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         The best tip is to do some reading on the subject.  You will have
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    a much better appreciation of what is going on with the programs.
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         How do you choose parameters to most effectively generate images?
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    Here are some general guidelines.
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         Generally, you will need more iterations the closer you get to the
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    edge of the set, and the higher you magnify.  To make a picture of the
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    whole set, as in "mama.1200.y", you can get away with iteration levels
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    of less than 100.  You may even wish to use a level of 10.  Higher
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    iteration levels are more accurate representations of the set.  The
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    fewer iterations you use, the more black area there will be in your
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    display.  As you increase the magnification, you may notice a fuzziness
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    to the set, and a lot of black dots speckling the image.  That is a
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    pretty good sign that you may need to increase the iteration limit.
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         The best guide to choosing iteration levels is the graph provided
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    in MANDELPAINT.  Look at the graph.  Suppose you chose a limit of 100.
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    If the vast majority of points fall well below 50, you could probably
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    have used a lower limit.  If there are points graphed nearer 100, you
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    may need to increase the limit on your next magnification.  As you look
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    at the graph, you should see decreasing levels of points as you move
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    towards the limit.  it is a good sign when you see some blank spots, or
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    gaps as you approach the limit.  This means there were no points
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    selected at those iteration levels.  That is a sign that you have
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    examined most of the points outiside the set, and a higher iteration
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    level would have made little difference.
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         The highest number of iterations that can be used with the system
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    is 2500.  MANDELCRUNCH could theoretically use values of over 32000,
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    but there is not enough memory for MANDELPAINT to handle this.
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    Fortunately, 2500 is quite high already.  Anything higher would almost
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    be impractical in terms of computation time.











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         If you examine a region of the set that contains no points within
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    the set (no black points), you will have 4 colors to work with, instead
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    of 3 colors and black.  Mandelpaint has been designed to make use of
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    this.  At this time, however, I have not written all of the programs to
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    do so.  To make use of it in AUTO-SEQ, for example, you will have to
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    change the HIRES and MULTI statements.
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         Another change that could be made is to use the COLOURS program to
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    create a custom color file that would be accessed by all the graphics
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    programs so you could use your favorite colors when working on the set.
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    However, I did want to upload what I have so far to see if anyone is
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    interested.
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         If you have any comments, questions, or suggestions, I would be
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    glad to hear from you.  Drop me a line on CompuServe e-mail for
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    73027,1316
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                      Best wishes,
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                          JA