Math Forum / Math Software / MATLAB / July 2008

Hi, I asked about this a little while ago, but now I have a
specific direction.  I'm trying to make density contours
based on the density of points in a scatter plot.  I want to
do this by making a grid, then making the contours based on

when ever I try to execute the program below it gives the
following message:
--------
??? Attempted to access ev(1,3); index must be a positive

I've justed switched to Vista64 bit and installed the R2008a
64bit Version, and am now setting up the system again.
I used to have a dualboot system with Linux, where
integrating compilers in Matlab wasnt a problem.

fill=[     0     0     0     0    -1    -1    -1;
    0     0     1     0     0    -1    -1;
    0     1    -1     1     0     0    -1;
    0     1    -1     1     0     0     0;

Why is not thesimulink block handle included in the "block"
input to level 2 mfile?
I know find_system command can get handles, but it would be
nice to have the handle directly.

Dear reader,
I build a model in Simulink and would like to estimate
parameters based on measured data. I found the
tool "Simulink Parameter Estimation". In the help document,

Hi ppl!
Hi have the following code which meshes a circular section
defined by yours truly :)
The 16 points that i coded for the boundary must always be

I meet a great problem with my mex-code in Fortran. I don't think I've
made any error. however after compiling, matlab cannot find this mex-
function.
for example:

i was testing out cell arrays and did this:
x = [1;2;3;4;5;6;7]
y = [1;2;3;4]
z = [1;2;3;4;5]

I would like to create a matrix in which each column is a function of the
previous column.  It is probably easiest to describe what I would like to
do with the following code :
M  is 20 x 100 matrix

I would like to produce a plot composed to two components.
First, a usual surface plot (eg. surf(X,Y,Z) )
Second, I would like to have a line plotted on the X-Z plane
of the previous plot, but with a second Z-axis.

I am very new to Matlab and need some help editing acoustic
room impulse responses together in Matlab.
What I have is a 24 sets of 40 impulse responses in WAV
format. What I need to do is to take the early reflections

I am using the fopen command but ran into some syntax
difficulty;
i read in the file name from a text file like this:
id = fopen('D:\Files.txt')

I'm interested in using Markov chain Monte Carlo to generate variates
from the inverse-gamma distribution via Metropolis-Hasting algorithm.
Below is the code I typed but I feel that the results after running
seem inappropriate, i.e., histogram does not follow inverse-gamma pdf.

I am studying function "rstool" to learn how it does the
regression. As I use "edit rstool" to see the code, on line
202, it uses function endfit. But when I want to look into
this function, I couldn't get into it. I tried to type the