On 11/26/09 12:23, Ian Liu wrote:
You can always map a 2d coordinate intto 1d:
(i, j) -> i * w + j
where w is the width of the matrix
That works poorly for dynamic arrays--every time you resize the array,
in either dimension, you basically have to copy all the elements to new
locations.
The general solution to multidimensional arrays in C is to use arrays of
pointers:
ptr0 -> e00 ee1 e02 e03 e04...
ptr1 -> e10 e11 e12 e13 e14...
ptr2 -> e20 e21 e22 e23 e24...
ptr3 -> e30 e31 e32 e33 e34...
.
.
.
This makes resizing fairly efficient--using reallocs--and can be
implemented using GArray
Ian L.
On Thu, Nov 26, 2009 at 3:04 PM, <mauede@xxxxxxxx
<mailto:mauede@xxxxxxxx>> wrote:
As far as I know a GArray grows an array of pointers in 1D not 2D.
I thought of a GArray myself but my question, although not clear, is
how can I use a GArray to grow a 2D array of structures ?
Can you please provide an example ?
Thank you in advance,
Maura
-----Messaggio originale-----
Da: tristan.van.berkom@xxxxxxxxx
<mailto:tristan.van.berkom@xxxxxxxxx> per conto di Tristan Van Berkom
Inviato: gio 26/11/2009 6.31
A: mauede@xxxxxxxx <mailto:mauede@xxxxxxxx>
Cc: gtk-list@xxxxxxxxx <mailto:gtk-list@xxxxxxxxx>
Oggetto: Re: dynamically growing 2D aray of structues
On Wed, Nov 25, 2009 at 9:17 PM, <mauede@xxxxxxxx
<mailto:mauede@xxxxxxxx>> wrote:
> I dare ask for some guidelines as I am not a programmer and
never came
> across glib before.
> At the time being I have to embed some code into a package
(Galopps: a
> Genetic Algorithm) which is totally implemented in C language.
> To be consistent with Galopps style I have to use glib functions.
> I have just started to use the simplest glib primitives and data
types.
> Now I am stuck with the following problem. I know there are a
lot of experts
> out there who can give me a couples of hints.
> I have to generate a 2D array of structures which grows
dynamically in both
> directions.
> The structure is defined as follows:
>
> typedef struct {
> gchar *id;
> gchar *description;
> gchar *sequence;
> gint sequence_len;
> } fasta_sequence;
>
Use a GArray:
http://library.gnome.org/devel/glib/stable/glib-Arrays.html
Cheers,
-Tristan
>
> Any suggestion is welcome.
> Thank you in advance,
> Maura
>
>
>
>
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Messenger e
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