Large arrays in GNAT

Large arrays in GNAT

[Reinert Korsnes]

Hi,

I cannot declare an array of Float larger than 2.5 mill elements
using my Ada95 gnat compiler (gnat-3.12p-12) on my linux box.

For example:

A : array (Integer range 1 .. 2_500_000) of Float;

results in "Segmentation fault (core dumped)".

For info: In Fortran (g77) I can declare much larger (Real) arrays.

Are there any options available under gnat so I can use arrays
of for example 5 mill elements of Float ?

reinert

--
Norwegian Polar Institute
Polar Environment Center
N-9296 Tromso
Norway
Fax: +47 77750501

http://geophys.npolar.no/~reinert/personal.html

Re: Large arrays in GNAT

[gdemont]

> I cannot declare an array of Float larger than 2.5 mill elements
> using my Ada95 gnat compiler (gnat-3.12p-12) on my linux box.

> A : array (Integer range 1 .. 2_500_000) of Float;

A is taken on the stack, so if the "exe" has a limit on that,
you have to extend this limit. A more comfortable way is to
allocate A in the heap - according to the OS, the only limit
is +/- the total user workspace in virtual memory (4 GB on
a 32-bit system).

type vector is array (Integer range <>) of Float;
type vector_a is access vector;

A: vector_a:= New vector(1 .. 2_500_000);

HTH
______________________________________________________
Gautier  --  http://members.xoom.com/gdemont/gsoft.htm


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Re: Large arrays in GNAT

[Reinert Korsnes]

You fixed my problem.   Thanks a lot....

reinert

Jeff Creem wrote:

> "Reinert Korsnes" <Reinert.Korsnes@npolar.no> wrote in message
> news:3971DC1F.D415BFBE@npolar.no...
> > Hi,
> >
> > I cannot declare an array of Float larger than 2.5 mill elements
> > using my Ada95 gnat compiler (gnat-3.12p-12) on my linux box.
> >
> > For example:
> >
> > A : array (Integer range 1 .. 2_500_000) of Float;
>
> declare the array in a package (spec or body it does not matter) or create
> an access type and do a new.
>
> If you declare an array as a local variable or (really the same thing) in
> the
> mainline procedure it gets created on the stack..

--
Norwegian Polar Institute
Polar Environment Center
N-9296 Tromso
Norway
Fax: +47 77750501

http://geophys.npolar.no/~reinert/personal.html

Re: Large arrays in GNAT

[Jeff Creem]

"Reinert Korsnes" <Reinert.Korsnes@npolar.no> wrote in message
news:3971DC1F.D415BFBE@npolar.no...
> Hi,
>
> I cannot declare an array of Float larger than 2.5 mill elements
> using my Ada95 gnat compiler (gnat-3.12p-12) on my linux box.
>
> For example:
>
> A : array (Integer range 1 .. 2_500_000) of Float;


declare the array in a package (spec or body it does not matter) or create
an access type and do a new.

If you declare an array as a local variable or (really the same thing) in
the
mainline procedure it gets created on the stack..