[LON-CAPA-users] Duplicated ids found

[Itay Furman]

On Sun, 27 Oct 2013, Raymond Batchelor wrote:

> It seems to me that the id="11" is used within the imported file (which imports yet another library file) and redundantly in the actual problem file to import the first library file.  I think you 'might' want to use an id other than "11" in your problem file, for the import.

I see.
I will make the changes and test them later, when the questions will 
not be in active use.

Thanks,
Itay

>
> ----- Original Message -----
> From: "Itay Furman" <itayf at nospammail.net>
> To: lon-capa-users at mail.lon-capa.org
> Sent: Sunday, 27 October, 2013 08:45:18
> Subject: [LON-CAPA-users] Duplicated ids found
>
> Hi,
>
> This is problem a newbie question. But I didn't find information on
> this. Sorry for that.
>
> After publishing a problem I get the following error message:
>
> [start]
> ERROR: Duplicated ids found, problem will operate incorrectly.
> Duplicated ids seen:
> 11
> This error occurred while processing response 12 in part
> [end]
>
> I could find in my code only a single id="11".
> Note that the numerical ids in
>   <import id="11">/res/jce/itayf/pub/lib/const_phys.library</import>
> and
>   <numericalresponse unit="C" format="2E" answer="$q" id="12">
> were added by lon-capa after publication.
>
> The code follows below.
>
> Thanks in advance,
> Itay
>
> [start code]
> <problem>
>   <comment>
>     File    = elec_coulomb_identical-hanging-charges.problem
>     Author  = Itay Furman, PhD, itayf at fastmail.fm
>     Created = 2013-10-08
>     Updated = 2013-10-08
>     Version = 0.01
>
>     Source  = Expanded from a problem by Michael Friedberg, JCE.
>   </comment>
>
>   <import id="11">/res/jce/itayf/pub/lib/const_phys.library</import>
>
>   <script type="loncapa/perl">
>     # Set-up
>
>     $k_coulomb = $Coulomb_Const;
>     $g      = 9.8;                                # Gravity acceleration [m / s^2].
>     $len    = &random(10, 50, 5);		  # String length [cm].
>     $theta  = &random(4,25,1);                    # Angle between string and vertical [degrees].
>     $th_rad = $theta* $Pi / 180;                  # Same angle [rad].
>     $mass   = &random(5,80,5);                    # Body mass [g].
>
>     # Compute the magnitude of the charge on each body.
>     $q = 2 * ($len/100) * sin($th_rad) * sqrt(($mass/1000) * $g * tan($th_rad) / $k_coulomb);
>     # Note the following factors are required:
>     # 1/100   in ($len/100)       to convert        $len: [cm]  -> [m].
>     # 1/1000  in ($mass/1000)     to convert       $mass: [g]   -> [kg].
>     # $Pi/180 in ($theta*$Pi/180) to convert sin()'s arg: [deg] -> [Rad].
>   </script>
>
>   <startouttext />
>   <h2>The Electrostatic Force Between a Pair of Identical Hanging Point Charges</h2>
>
>   <p>
>     Two point bodies, each having a mass of <num>$mass</num> [g], are connected to identical massless
>     isolating strings whose length is <num>$len</num> [cm].
>     The strings are connected to the same hook on the ceiling.
>   </p>
>   <p>
>     The bodies carry identical charges.
>     Therefore, due to electrostatic repulsion, each string is inclined with an angle of
>     $theta<sup>o</sup> relative to the line that pass through the hook and is orthogonal to the
>     ceiling.
>   </p>
>   <endouttext />
>
>   <part id="q" display="Compute the charge.">
>     <startouttext />
>     <strong>Compute: </strong> the electric charge on each body is
>     <endouttext />
>
>     <numericalresponse unit="C" format="2E" answer="$q" id="12">
>       <responseparam name="tol" type="tolerance" default="2%" description="Numerical Tolerance" />
>       <textline readonly="no" />
>     </numericalresponse>
>   </part>
>
>   <img alt="A pair of identical hanging charged masses."
> src="/res/jce/itayf/pub/share/img/131012_pair-hanging-charges.jpg"
> encrypturl="no" />
> <allow
> src="/res/jce/itayf/pub/share/img/131012_pair-hanging-charges.jpg" />
> </problem>
>
> [end code]
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