Math Forum / Math Software / MATLAB / July 2008

How do you define the varible x and y varible in matlab r2007b?
I tried to do sym x y and syms x y, but it keeps on saying
"??? Undefined function or method 'sym' for input arguments
of type 'char'."

I would like to create a cell array of string numbers from
1 to 61.  In other words, I want a cell array of 61 cells
with strings '1', '2', .... '61' stored in each cell.  How
can I do that easily?

I have a code which reads a file in fortran and creates a 4
dimensional matrix. The file is in mixed format and I dont
want to recode the thing in matlab, as I think it would be
cumbersome. So I was thinking I could call the fortran as a

I am wondering if it is possible to create a bar plot with
bars of varying width. In other words, for example, the
first bar could be width 1, while the second width 1.3, then
0.7, etc.

Does anyone know of a way to plot more than 2 plots (let's
say 10) in the same figure? Each plot has different ranges
for x and y. And I cannot use subplot.
Thanks a lot!

I searched the group for this, but did not find an answer.
Many of the matlab functions (e.g. polybool) and other GIS-tools
expect the points of an outer boundary of a contour to be given in
clockwise order, and "holes" in counterclockwise order.

I have a loop that makes a conditional mathematical
operation on a column. I want to grab the outputs of each
iteration, put gather them in one array to replace the
original column before calculation.

Let's say I'm reading in a csv data file with 3 columns:
Day #, Type of Dog, and the # of barks.
I'm reading them into a data structure barkData(i)
barkData(i).day

I have files with a great number of columns (200+) that needs to be
imported into Matlab.  I have to (to the best of my knowledge) use
textscan to imoprt them because I am processing multiple files and
this is only possible with use of a fid and textscan, so far as I

Hello, I need a function to be called on a pushbutton
being pressed, not released. I can make the ButtonDownFcn
work on a figure, or an axis, but not a pushbutton. This
is the simple example I'm trying to get to work.

I have created a gui with a few pushbuttons and 3 plots using plot3
and subplot command. I am also updating all of the 3 plots with images
slice-by slice i.e., moving images. Help needed in 2 areas:
1) I could display all images using plot3 command, but they overlay on

Whenever my Matlab program is debugged, the previously set
breakpoints disappear. If I debug once again, I have to
reset the breakpoints. How to set the breakpoints just for
once and keep them until I delete them?

I was wondering if there is a way to search within a matrix
of 2x10
This search would point out a value which has
repeated within the same row 3 times. This value

I have some code as follows:
a=rand(50,16)
b=pi*a.^2
f=1:100

I could need some help to rewrite a for loop into MATLAB
pointwise syntax:
for ii = 1:length(RAY)
    r_dir(ii,1:3) = (M*RAY(ii).dir(1:3)')';