traj.gs

[Ted Pollock]

Thank you very much. It worked.

Quoting Takashi Kagimoto <kagimoto at JAMSTEC.GO.JP>:

> Dear Ted,
>
> From: Ted Pollock <edwardp at UALBERTA.CA>
> Subject: traj.gs
> Date: Wed, 8 Aug 2007 23:36:33 +0200
>
>> I am running the script traj.gs on some high temporal resolution MM5 data.
>> The script has to be run 49 times per output image file. The trouble is that
>> after around 5 to 6 trajectory calculations grads crashes with the following
>> error: Segmentation fault (core dumped). Each trajectory calculation runs
>> slower then the last so it is some kind of memory problem but the coredump
>> file size is only 5.2 Mb.
>>
>> I have tried setting the memory limits and core dump size very high with
>> little success.
>
> I think this is a potential bug in GrADS. Looking at src/gauser.c,
> you will see a counter that express how many times d(isplay)
> command is spawn, pcm->pass. This counter will increase forever
> unless you run c(lear) command or you draw a sort of animation.
> In fact, there are thousands of d(isplay) commands in traj.gs.
> So what is the problem in this counter? The counter is used to
> determine a color of an object, if you do not specify it, in the
> way of dcolor[pcm->pass+1], which is defined in the function of
> gadspl() as to be in the following,
>
>   static int dcolor[10] = {-1, 1, 3, 7, 2, 6, 9, 10, 11, 12 };
>
> What will happen when the counter value becomes larger than or
> equal to 10. If the memory address corresponding to dcolor[n],
> although it's grammatically an illegal access, is a sort of data
> area that is assigned to your program (in this case, GrADS), you
> may luckily draw an object with some color, where n is any negative
> value or any value larger than or equal to 10. If not, you will
> encounter the segmentation fault.
>
> I attached a patch file to modify this problem for GrADS 1.9b4.
> Namely you need to build executables of grads from source codes.
> Hope you will successfully do it.
>
> Best regard
> ----
> Takashi Kagimoto
> Frontier Research Center for Global Change/JAMSTEC
> 3173-25 Showamachi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, JAPAN
> (tel) +81-45-778-5516 (fax) +81-45-778-5707
>
>