Thread Subject: Simulink crashes when using fixed point sqrt

Hello
I'm trying to use the fixed-point toolbox with Simulink, but
I have some problems with it.
My version of Matlab is 2007a
To start with an easy one (or so I thought), I connected a
constant block to an sqrt one (from 'math function') and
then to a scope.
I first set the sqrt output to a 16bits long word, and there
was no problem. When I input more, the simulation doesn't
start but doesn't return any error message. From that moment
on, every simulation will fail, even I put double as the
output type. I have to restart Matlab.
Where did I go wrong?

"Kevin " <kedecuyp@mathworks.com> wrote in message
<g1p353$88r$1@fred.mathworks.com>...
> Hello
> I'm trying to use the fixed-point toolbox with Simulink, but
> I have some problems with it.
> My version of Matlab is 2007a
> To start with an easy one (or so I thought), I connected a
> constant block to an sqrt one (from 'math function') and
> then to a scope.
> I first set the sqrt output to a 16bits long word, and there
> was no problem. When I input more, the simulation doesn't
> start but doesn't return any error message. From that moment
> on, every simulation will fail, even I put double as the
> output type. I have to restart Matlab.
> Where did I go wrong?
By 'more', I wanted to say 'a word with more bits'

Hi Kevin,
Would it possible for you to attach/send me a model that reproduces this
problem? Also, what was the type of your input the first time and then the
second time?
I may be able to help you if I have some more information.
Thanks,
Ashok Charry
The MathWorks Inc.



On 5/30/08 10:51 AM, in article g1p48m$lvc$1@fred.mathworks.com, "Kevin"
<kedecuyp@mathworks.com> wrote:

> "Kevin " <kedecuyp@mathworks.com> wrote in message
> <g1p353$88r$1@fred.mathworks.com>...
>> Hello
>> I'm trying to use the fixed-point toolbox with Simulink, but
>> I have some problems with it.
>> My version of Matlab is 2007a
>> To start with an easy one (or so I thought), I connected a
>> constant block to an sqrt one (from 'math function') and
>> then to a scope.
>> I first set the sqrt output to a 16bits long word, and there
>> was no problem. When I input more, the simulation doesn't
>> start but doesn't return any error message. From that moment
>> on, every simulation will fail, even I put double as the
>> output type. I have to restart Matlab.
>> Where did I go wrong?
> By 'more', I wanted to say 'a word with more bits'