how to use dbstop if naninf

I want to ask matlab to stop anywhere in my functions, a variable becomes nan or inf. I defined a function buggy(x) (which is a matlab example in help page of dbstop).

    function z = buggy(x)
    n = length(x);
    u=8/0
    z = (1:n)./x;

I just added one line ( u=8/0) to see how dbstop if naninf works. when I ran, matlab started violating. The response is in the following code:

>> dbstop if naninf
>> buggy(3)

u =

     Inf

NaN/Inf breakpoint hit for buggy on line 3.
Stopping at next line.
3   u=8/0
4   z = (1:n)./x;
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
20  if ~isfloat(value)
399     if numel(var) > numelLimit
20  if ~isfloat(value)
...and continuing...

and matlab stays in debugging mode and if I try doing something in matlab, it freezez.

Am I using dbstop in a wrong syntax or a wrong place?

I want matlab to stop and any inf/nan that that I have produced in my own codes. apparently it stops in its own built-in matlab files as well.

[John Hatrick]

I have this problem too!

setting 'dbstop if naninf' finds tons of inf statements in MATLAB scripts I'm not using such as 'fsolve.m' and 'trustnleq.m.'

I want to find if a variable goes NaN; I don't care if the phrase 'inf' shows up in a script...

Respectfully, John

Answer 1

[Matt J]

You're definitely not doing anything wrong. It works fine for me. What version of MATLAB is this? Maybe try again after restarting MATLAB? Or maybe try reinstalling.

[Habib]

Matlab 2009a. I have to upgrade to the 2012b in a few days. Thanks buddy for trying the code.