Something wrong with as_matrix operator

[pcaillou]

What steps will reproduce the problem?
1. Import project AsMatrix
2. run model1

What is the expected output? 
-> GAMA displays the values of the matrix
What do you see instead?
-> Exception "Index location[0.0;0.0;0.0] out of bounds of testMat"

What version of the product are you using?
-> 1.6.1 SVN
On what operating system?
-> MAC OSX 

Please provide any additional information below.

Original issue reported on code.google.com by lvminh2k on 2014-03-15 11:34:19

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• Attachment: AsMatrix.zip

[pcaillou]

You should not use the operator "as_matrix" as you use it. 
If you want to create a matrix of {2,2}, you should use: matrix testMat <- 0 as_matrix
({2, 2});

Otherwise, GAMA don't know what to put in the matrix and build a empty matrix.

But it is true I do not know the good way to create a matrix composed of empty lists:
[];[]
[];[]

Original issue reported on code.google.com by patrick.taillandier on 2014-03-15 15:25:44

[pcaillou]

(No text was entered with this change)

Original issue reported on code.google.com by patrick.taillandier on 2014-03-15 19:33:23

• Labels added: Milestone-1.6.1

[pcaillou]

There are many ways to create and fill matrices, but I think you have uncovered a bug
due to the ambiguity of the 'as_matrix' operator.

If you declare an attribute of a species, you would not have this problem, because
you could use the handy 'size:' and 'fill_with:' facets:

global {
    matrix<list> m size: {10,10} fill_with: [];
    …
}

However, when declaring a temporary variable, these options are not (yet) available.
And your intuition was good in using the 'as_matrix' operator, but its operational
semantics is definitely flawed: when the left-side argument is a container, 'as_matrix'
tries to convert this container to a matrix of the given size, but when you have something
else than a container it uses this left-side value to fill the matrix. So there is
no way to make it create a matrix of list, for instance, with this method.

You then have two workarounds : 

1) (provided you update your code base, as I've been forced to fix some issues pertaining
to this construct):

matrix<list> m2 <- nil as_matrix {10,10};
m2[] <- [];

2) 

list<list> lists <- [];
loop times: 100 {lists <+ [];}
matrix<list> m2 <- lists as_matrix {10, 10};

====

Finally, in order to remove the ambiguity present in 'as_matrix', I've also added a
new operator called 'matrix_with', which uses the same arguments (but in a different
order), and makes it clear that the second argument is used to fill the matrix (and
not to be casted into a matrix).

So, in your case, it would be, for instance :

matrix<list> m2 <- {10,10} matrix_with [];

I have committed all the changes. 

Original issue reported on code.google.com by alexis.drogoul on 2014-03-15 19:36:48