Graphics Programs Reference
You may have noticed that the semi-annular region does not appear
as a circular segment in our plots. That is because the axes are not
square. To get square axes you can use the axis square command as
described on pages 18 and 120.
In this section we have looked at surfaces having domains that could
be defined in terms of rectangular x and y data matrices. Domains
that cannot be defined with such matrics are discussed in section 36 on
page 157. For example all x values may not have the same number of y
values, or the x, y points could be scattered about in an irregular way.
Until now we have driven matlab by typing in commands directly. This
is fine for simple tasks, but for more complex ones we can store the typed
input into a file and tell matlab to get its input from the file. Such files
must have the extension “ .m ”. They are called m-files. If an m-file
contains matlab statements just as you would type them into matlab,
they are called scripts . M-files can also accept input and produce output,
in which case they are called functions .
Using your text editor create a file called mfile1.m containing the fol-
z = peaks;
zplot = z;
% Do the peaks:
ind = find(z<0);
zplot(ind) = zeros(size(ind));