[LON-CAPA-users] Unordered Response Question Error

Carl Lira lira at egr.msu.edu
Tue Jan 24 20:15:46 EST 2017


I don't see the script, but you need to have a tolerance. When the value is
not specified, it defaults to an absolute tolerance of zero. If a floating
point calculation is done, it will never be exactly an integer. From the
author manual:

 

A tolerance parameter determines how closely the system will require the
student's

answer to be in order to count it correct. The tolerance will default to
zero if it is not

defined. The tolerance parameter should always be defined for a numerical
problem

unless you are certain only integer answers are generated from your script
and you

want students to reply with exactly that integer.

If the computer answer is a floating point number, the tolerance should not
be zero.

Computers can only approximate computations involving real numbers. For
instance,

a computer's [decimal] answer to the simple problem 1

3 is "0.33333333333333331". It

should be an infinite series of 3's, and there certainly shouldn't be a "1"
in the an-

swer, but no computer can represent an infinitely long, infinitely detailed
real number.

Therefore, for any problem where the answer is not an integer, you need to
allow a

tolerance factor, or the students will find it nearly impossible to exactly
match the

computer's idea of the answer. You may find the default tolerance too large
for some

problems, so adjust as appropriate.

 

 

Hm, I think that last line should say "if you use the colorful editor
tolerance template, the default tolerance may be too large...". I think the
template defaults to 5%. 

 

the format affects the display, not the calculations.

 

From: lon-capa-users-bounces at mail.lon-capa.org
[mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Harding, Gene
L
Sent: Tuesday, January 24, 2017 8:23 AM
To: Discussion list for LON-CAPA users <lon-capa-users at mail.lon-capa.org>
Subject: Re: [LON-CAPA-users] Unordered Response Question Error

 

Hi Carl,

 

The ! was commenting out the parameter, something I tried among several
permutations of syntax hoping to get something to work. The error message is
the same whether it is there or commented out. I originally also had a sig
figs param in it, but deleted it. I think that eliminated one error.

 

I have tried putting the unit= and format= in the answer and value fields,
but no luck there, either.

 

Gene L. Harding, PE

Associate Professor of ECET

574-520-4190

Purdue University-South Bend

 

From: lon-capa-users-bounces at mail.lon-capa.org
<mailto:lon-capa-users-bounces at mail.lon-capa.org>
[mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Carl Lira
Sent: Monday, January 23, 2017 11:22 PM
To: 'Discussion list for LON-CAPA users' <lon-capa-users at mail.lon-capa.org
<mailto:lon-capa-users at mail.lon-capa.org> >
Subject: Re: [LON-CAPA-users] Unordered Response Question Error

 

not sure of the impact of the ! in the responseparam field. I believe you
should have some tolerance if you have a calculated real number, e.g.

 

<responseparam name="tol" type="tolerance" default="2%"
description="Numerical Tolerance" />

 

 

 

 

From: lon-capa-users-bounces at mail.lon-capa.org
<mailto:lon-capa-users-bounces at mail.lon-capa.org>
[mailto:lon-capa-users-bounces at mail.lon-capa.org] On Behalf Of Harding, Gene
L
Sent: Monday, January 23, 2017 10:00 PM
To: 'lon-capa-users at mail.lon-capa.org' <lon-capa-users at mail.lon-capa.org
<mailto:lon-capa-users at mail.lon-capa.org> >
Subject: [LON-CAPA-users] Unordered Response Question Error

 

Hi,

 

I am trying to embed some unordered numericalresponse parameters inside an
xml table. I modeled my xml after the example in LON-CAPA, but am having two
problems with it. The first problem is an error referring to tolerance
range, and the second is incompatible units. This is a screenshot:



 

This is the code I am using:

<startouttext />

A $Pa dBm, $fa-MHz RF input signal and a $Pb dBm, $fb-MHz LO signal are
applied to a nonlinear mixer with $Zin-Ω impedance. Complete the table
of IF cross products for m,n equal 1,2.

 

<! Display numeric response inside a table >

<table style="width:400px" border="1" cellpadding="1" >

  <tr>

    <td> m </td>  <td> n </td>  <td> |mf<sub>a</sub> ±
nf<sub>b</sub>| </td>  <td> Cross Products </td>

  </tr>

  <tr>

    <td>1</td>  <td>1</td>  

    <td>

<numericalresponse format="0f" unit="MHz" id="11">

    <answergroup type="ordered">

        <answer type="unordered">

            <value>$fa</value>

            <value>$fb</value>

        </answer>

    </answergroup>

    <!responseparam name="tol" type="tolerance" default="0"
description="Numerical Tolerance" />

    <textline size="8" readonly="no" />

    <textline size="8" readonly="no" />

</numericalresponse>

    </td>  <td>$f11_1 MHz $f11_2 MHz</td>

  </tr>

  <tr>

    <td>1</td>  <td>2</td>  

  </tr>

  <tr>

    <td>2</td>  <td>1</td>  

  </tr>

  <tr>

    <td>2</td>  <td>2</td>  

  </tr>

</table>

 

<endouttext />

 

Any ideas why I am getting these two errors?

 

Thanks for any advice you can provide.

 

Best regards,

 

Gene L. Harding, PE

Associate Professor of ECET

574-520-4190

Purdue University-South Bend

 

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