$GDXIN problem

[Fabián Mancilla]

I'm trying to load data (subsets and parameters) from a GDX file. I have a system  with two matrices (A and M) but GAMS read the matrix A like a zeros matrix (all coeficients are zero!), but the matrix A have 987 non zero elements. I used the command 'load' in $GDXIN:

*Model form:

*     min cx

* s.t.

*      Ax < b

*      Mx = g

SETS

i rows matrix A /j1*j559/

j columns matrices A & M /j1*j505/

k rows matrix M /k1*k128/

jcon(j) continue columns

jint(j) integer columnas

jbin(j) binary columns;

PARAMETERS

A(i,j) matrix A

M(k,j) matrix M

b(i)   vector b

g(k)   vector g

c(j)   vector c;

$GDXIN GDXfile.gdx

$load jcon

$load jint

$load jbin

$load b

$load M

$load A

$load g

$load c

$GDXIN

DISPLAY A, M, jcon, jint, jbin;

But the display is:

----     33 PARAMETER A  matrix A

                      ( ALL       0.000 )

----     33 PARAMETER M  matrix M

              j2          j3          j4          j5          j6          j7

k17        1.000

k18                    1.000

k19                                1.000

k20                                            1.000

k21                                                        1.000

k22                                                                    1.000

I don't know why this is happening. Anyone can advice me?

Thanks!

Fabián

[Dol, Wietse]

Hi Fabian,

 

When you try to  read from GDX and you get an empty parameter it simply means that you have used wrong indices (sets), i.e. this can happen because you swapped two indices/sets in the parameter declaration (in your case this is not true). The second reason is that you have wrong elements. In your case you define the set i:

i rows matrix A /j1*j559/

but when you look at your GDXfile you will see

i rows matrix A /i1*i559/

So correct this and it should work

 

Wietse

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[Steven Dirkse]

If you expect all of the elements in the GDX data to be loaded, you
can also use $loaddc (load with Domain Check), e.g.

$loaddc M
$loaddc A

$load and $load dc are similar. The difference is that $load ignores
elements that don't fit into the declared domain of the data, while
$loaddc flags them as errors.

-Steve

2012/4/16 Fabián Mancilla <mancill...@gmail.com>:

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[imo]

Many thanks to Steven.
I used to have the exact same problem and with $load dc the error was
evident. It took me a while to figure it out, so I will always use
domain checking from now on.

Cheers.
+i

On Apr 17, 2:32 pm, Steven Dirkse <sdir...@gams.com> wrote:
> If you expect all of the elements in the GDX data to be loaded, you
> can also use $loaddc (load with Domain Check), e.g.
>
> $loaddc M
> $loaddc A
>
> $load and $load dc are similar.  The difference is that $load ignores
> elements that don't fit into the declared domain of the data, while
> $loaddc flags them as errors.
>
> -Steve
>

> 2012/4/16 Fabián Mancilla <mancilla.fab...@gmail.com>:

> sdir...@gams.comhttp://www.gams.com

[Fabián Mancilla]

I didn't see my mistake in the indices set. The load with Domain Check is very useful!

Thanks to both!