Cannot calculate with Dynamic variables

• To: mathgroup at smc.vnet.net
• Subject: [mg128735] Cannot calculate with Dynamic variables
• From: Reinhard Simonovits <Reinhard.Simonovits at uni-graz.at>
• Date: Wed, 21 Nov 2012 19:51:15 -0500 (EST)
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• Delivered-to: l-mathgroup@wolfram.com
• Delivered-to: mathgroup-newout@smc.vnet.net
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```Hi,

I have a problem with Dynamic variables.

This is a prototype of a grading scheme. In reality it is bigger. The
10 pts  in initPtsPartAcome from the school.

The output cell should be deployed as a CDF file for the teacher. The
teacher enters the points of the students and gets a final mark.

I have two questions.

1) How can I limit the InputField to allow for integer numbers between 0
and 10?  If I enter anything else, say a negative number or a symbol,
it should be cleared automatically.

2) In  "Why don't the calculations work?" you see expressions with
Dynamic variables which I need to work with. What is wrong? What is the
solution?

DynamicModule[ {mark4 = 1/3,
mark3 = 0.51,
mark2 = 0.68,
mark1 = 0.80,
initPtsPartA = {
{10, 8, 10, 6},
{10, 5, 10, 5},
{10, 7, 10, 1}},
initPtsStudent, initPtsSchool, initPtsPartSum, numTable,
SchoolAPts, StudentAPts, StudentMinAchieved
},

numTable[x_, y_ /; OddQ[y]] := initPtsPartA[[x, y]];
numTable[x_, y_ /; EvenQ[y]] :=
InputField[Dynamic@initPtsPartA[[x, y]], Number,
ContinuousAction -> True, FieldSize -> 1];

initPtsPartSum[x_, y_, col_] :=
Dynamic@Total[initPtsPartA[[x ;; y, col]]];

SchoolAPts = (Total[initPtsPartA[[1 ;; 3, #]]] &) /@ {1, 3};
StudentAPts = (initPtsPartSum[1, 3, #] &) /@ {2, 4};

Column[{Grid[
Append[ Array[numTable, {3, 4}], (initPtsPartSum[1, 3, #] &) /@
Range[4]]],

{"Just Testing Values:", initPtsPartSum[1, 3, 1],
initPtsPartSum[1, 3, 2], initPtsPartSum[1, 3, 3],
initPtsPartSum[1, 3, 4], "Student Pts only:", StudentAPts},

{"Why don't the calculations work?",
Dynamic[5*initPtsPartSum[1, 3, 2] + 10],
Dynamic[initPtsPartSum[1, 3, 4] > 30],
Dynamic[ Total[(initPtsPartSum[1, 3, #] &) /@ Range[4]]  ],
Dynamic[(Total@StudentAPts)]/(Total@SchoolAPts)},

{"Why don't the calculations work?",
StudentMinAchieved =
Dynamic[(StudentAPts[[1]]/SchoolAPts[[1]] >
mark4) && (StudentAPts[[2]]/SchoolAPts[[2]] > mark4)]}

}]

]

Liebe Grüße, Best wishes, Reinhard

--
*********************************************************
Dr. Reinhard Simonovits
Handelsakademie  |  Karl Franzens University
Math Department  |  Inst. for Mathematics
Grazbachgasse 71 |  Heinrichstrasse 36
A-8010 Graz, Austria

Email: Reinhard.Simonovits at uni-graz.at
************************************************************

```

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