Question:

I am trying to learn optaplanner. And as a learning project I am trying to implement a very basic and simple program which calculates "<a href="http://en.wikipedia.org/wiki/Magic_square" rel="nofollow">magic squares</a>".

Basically I am trying to assign "Number"s to the "Box"es defined in rows and columns.

Sorry for not copy/pasting directly from source code, my development machine can not connect to internet so I will try to write down important part of classes by hand.

My domain structure is as follows:

<blockquote>

@PlanningSolution MagicSquareSolution

//facts List<Column> columnList List<Row> rowList List<Number> numberList //entity List<Box> boxList @valueRangeProvider (id="numberRange") getNumberList() @PlanningEntityCollectionProperty getBoxList </blockquote> <hr /><blockquote>

@PlanningEntity Box

Column column Row row Number number // planningVariable @PlanningVariable(valueRangeProviderRefs="{numberRange}") getNumber </blockquote>

I am using a SIMPLE Java score calculator class.

In my solver configuration xml I used FIRST_FIT and FIRST_NON_DETERIRATING_SCORE.

The problem is; in the solution I got, numbers are reused like

7 5 3 1 5 9 7 5 3

Here you can see although the sum of rows and columns are equal to 15; Numbers 7,5 and 3 are used multiple times. How can I enforce the all the values in the value range for the planning variable is used at least once and only once.

Thanks.

Akif,

Add a score constraint:

when Box($n : number, $id : id) Box(number == $n, $id > id) then // -1 hard