[LON-CAPA-users] Puzzling situation...

[Mills, Douglas G]

Hi Stuart,

Thank you. Would that then explain the following bomb message:

Sun Feb 24 06:15:32 pm 2013 (CST): Computer's answer is incorrect
("0.00"). It is likely that the tolerance range [5.488e-17, 5.712e-17] or
significant figures [1, 2] need to be adjusted.
This error occurred while processing response 25 in part 320
The error occurred on host uiucaccess2
This error occurred on machine uiucaccess2

And if so, how should we be accomplishing what we are trying to do?
Thanks!


Doug

Douglas Mills
Director of Instructional Technologies
Department of Chemistry
University of Illinois
dmills at illinois.edu
(217) 244-5739







On 2/22/13 1:23 PM, "Stuart Raeburn" <raeburn at msu.edu> wrote:

>Hi,
>
>> Any ideas anyone on why in the second instance ($db12, id=25) 0 is
>> accepted as a correct answer but in the other instance ($dy11,
>> id=22), 0 is returned as incorrect???
>
>Perhaps you are seeing an artifact of floating point calculations in
>the situation where the answer is zero, and you are using a relative
>tolerance?
>
>Stuart Raeburn
>LON-CAPA Academic Consortium
>
>
>Quoting "Mills, Douglas G" <dmills at illinois.edu>:
>
>> HI All,
>>
>> We're greatly perplexed by this situation.  We have a student whose
>> results for two different responses in a part should be 0, but the
>> answer is accepted for one of the responses and not accepted for the
>>  other. To the best of my abilities to discern, everything about the
>>  two items is identical (and having written these, it's almost
>> certain that I cut and pasted my way from one to the other) and the
>> data for the two are analogous.
>>
>> The formulas for computing the two answers are:
>>
>> $dY11=&format($EAY11-$AY11,"2s");
>> $dB12=&format($EAB12-$AB12,"2s");
>>
>> The values for the variables in her instance are:
>>
>> $EAY11=4.2e-1
>>
>> $AY11=.42
>>
>> $EAB12=2.6e-1
>>
>> $AB12=.26
>>
>> The coding in the problems looks (is!?) identical as well:
>>
>> <numericalresponse format="2f" answer="$dY11" id="22">
>> <responseparam name="tol" type="tolerance" default="2%"
>> description="Numerical Tolerance" />
>> <responseparam name="sig" type="int_range" default="1,2"
>> description="Significant Digits" />
>> <textline /> $PART20msg[1]
>> </numericalresponse>
>>
>> <numericalresponse format="2f" answer="$dB12" id="25">
>> <responseparam name="tol" type="tolerance" default="2%"
>> description="Numerical Tolerance" />
>> <responseparam name="sig" type="int_range" default="1,2"
>> description="Significant Digits" />
>> <textline /> $PART20msg[4]
>> </numericalresponse>
>>
>> Any ideas anyone on why in the second instance ($db12, id=25) 0 is
>> accepted as a correct answer but in the other instance ($dy11,
>> id=22), 0 is returned as incorrect???
>>
>> Doug
>>
>> Douglas Mills
>> Director of Instructional Technologies
>> Department of Chemistry
>> University of Illinois
>> dmills at illinois.edu<mailto:dmills at illinois.edu>
>> (217) 244-5739
>>
>
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