Thread Subject:

mxCreateString usage

Hello everyone,

I'm trying to start a simulation from within an S-Function which is in my initial simulation.
I'm using mxCallMATLAB and the function sim.

My problem is the following:
I need to execute the sim function with a couple of parameters. I want to pass them as a string and for that I'm using mxCreateString:

const char *option = "'example.mdl',35:60";
    mxArray *prhs = mxCreateString(option);
    mexCallMATLAB(0,NULL,1,&prhs,"sim");

the error that I get is:
The file name ''example.mdl',35:60' is invalid because it does not have the extension ".mdl" or ".slx".

The problem is that when I use mxCreateString it appends ' characters at the beginning and at the end of my string.

Any idea on how so solve this?
Your help is greatly appreciated.

Alin

 mexCallMATLAB and sim are working as expected.

You are asking mexCallMATLAB to call sim with one input that is a string.
When sim is called with one input that is a string it requires that string to be the name of a model, which in your case it is not, and hence it errors out, giving you a message that the string doesn't correspond to a model file.

What it looks like you really want it to call sim with two inputs -- the first being a string and the second being a numeric valued matrix.

Phil.

"Alin " <alin.ionascu@live.com> wrote in message <jt46uj$jor$1@newscl01ah.mathworks.com>...
> Hello everyone,
>
> I'm trying to start a simulation from within an S-Function which is in my initial simulation.
> I'm using mxCallMATLAB and the function sim.
>
> My problem is the following:
> I need to execute the sim function with a couple of parameters. I want to pass them as a string and for that I'm using mxCreateString:
>
> const char *option = "'example.mdl',35:60";
> mxArray *prhs = mxCreateString(option);
> mexCallMATLAB(0,NULL,1,&prhs,"sim");
>
> the error that I get is:
> The file name ''example.mdl',35:60' is invalid because it does not have the extension ".mdl" or ".slx".
>
> The problem is that when I use mxCreateString it appends ' characters at the beginning and at the end of my string.
>
> Any idea on how so solve this?
> Your help is greatly appreciated.
>
> Alin


Hi Phil,

Thanks for your response.
The next question will be: how do I do this ?
How do I call the sim function with 2 arguments of different types.
In the command window the call would look like this:

sim('example.mdl',40:90); //the second argument is the time simulation interval

Could you please tell me how to call this function with mexCallMATLAB (the code) ?

Thank you.
Best Regards,

Alin

"Alin " <alin.ionascu@live.com> wrote in message
news:jte5vv$jv8$1@newscl01ah.mathworks.com...
> "Alin " <alin.ionascu@live.com> wrote in message
> <jt46uj$jor$1@newscl01ah.mathworks.com>...
>> Hello everyone,
>>
>> I'm trying to start a simulation from within an S-Function which is in my
>> initial simulation.
>> I'm using mxCallMATLAB and the function sim.
>>
>> My problem is the following:
>> I need to execute the sim function with a couple of parameters. I want to
>> pass them as a string and for that I'm using mxCreateString:
>>
>> const char *option = "'example.mdl',35:60";
>> mxArray *prhs = mxCreateString(option);
>> mexCallMATLAB(0,NULL,1,&prhs,"sim");
>>
>> the error that I get is:
>> The file name ''example.mdl',35:60' is invalid because it does not have
>> the extension ".mdl" or ".slx".
>>
>> The problem is that when I use mxCreateString it appends ' characters at
>> the beginning and at the end of my string.
>>
>> Any idea on how so solve this?
>> Your help is greatly appreciated.
>>
>> Alin
>
>
> Hi Phil,
>
> Thanks for your response. The next question will be: how do I do this ?
> How do I call the sim function with 2 arguments of different types.
> In the command window the call would look like this:
>
> sim('example.mdl',40:90); //the second argument is the time simulation
> interval
>
> Could you please tell me how to call this function with mexCallMATLAB
> (the code) ?

Make prhs an array of mxArray*'s. Fill in the first element in that array
with your string and the second with the vector 35:60; the
mxCreateNumericMatrix and mxGetPr functions will be of use to you in
creating that vector. Take a look at the arrayFillGetPr.c example on
mxGetPr's documentation page for an example that you should be able to
adapt.

http://www.mathworks.com/help/techdoc/apiref/mxgetpr.html

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Steve Lord
slord@mathworks.com
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