The input file begins with an integer n, followed by
four real values: xmin, ymin, xmax, and
ymax in this order. It is followed by a 256-by-3
table of real-valued color gradations. (There is no need to even read
in these 768 values for the grayscale image.)
Don't be misled by the text next to the
mand4.txt picture in the assignment -- sorry.
For example, the file
mand4.txt is:
4
-1.5 -1.0 0.5 1.0
0.000 0.000 0.734
0.000 0.300 0.734
. . .
0.000 0.000 0.000
Checking Your Work and Hints
|
Here is the correct sequence of Mandelbrot iterates for the point (0.125, 0.750).
Your function should return 6, not 5 or 7.
#
| 0
| 1
| 2
| 3
| 4
| 5
| 6
|
r
| 0.125000
-0.421875
-0.575928
0.455010
-0.303564
-1.959975
3.945239
s
| 0.750000
0.937500
-0.041016
0.797244
1.475509
-0.145822
1.321613
| | | | | | | | | | | | | |
Run your program on some of the data files in
/u/cs126/files/mandel/.
You may use the programs mandgray126 and
mandcolor126 to check your programs against our reference solutions.
Step-by-step instructions for getting started and additional hints are available
here.
If you are new to program and/or are struggling, this may be the best place to start.
If you have some programming experienced you are probably better off by not peeking.
The file
/u/cs126/files/mandel/test.c
is an example of a C program that produces a PostScript program.
It produces the sample PostScript program in the assignment by
a series of printf() statements.
Compile your program with "gcc mandgray.c"
or preferably "gcc126 mandgray.c".
To redirect the file mand4.txt as input and redirect the output to
the file mandgray4.ps, use the command:
a.out < mand4.txt > mandgray4.ps
Now, you can view the PostScript program with the command:
gs mandgray4.ps
Note that the gs command will not work from a telnet session.
Do not print any PostScript file unless it views
properly with gs.
If your program doesn't produce valid PostScript (e.g., it doesn't
print properly with lpr126), then rename your files as
mandgray-bad.c
or mandcolor-bad.c. Otherwise your grader may waste paper and
effort trying to print the output.
You will receive a deduction of up to 20 points if you don't
follow these instructions.
Use the following submit command:
submit126 2 readme mandgray.c mandcolor.c
Do not use different file names.
Do not submit a.out. Do not submit PostScript files.
The readme file should contain
Name, precept number.
High level description of code.
Describe any serious problems you encountered. List
whatever help that you received (including using the hints link).
Do not include PostScript output in the readme file.
Use at most 80 characters per line to ensure that your grader
can view it properly.
Here's a
readme file template.
There is a huge amount of information on the Web about
fractals, including a
Mandelbrot tutorial
and a
Mandelbrot generator.
Check out the
PostScript section
of the COS 126 FAQ List
for more information on PostScript
(although you shouldn't need much more info for this assignment).
It includes a link to download a PostScript viewer for
your PC or Mac.
Kevin Wayne