bombing out writing large scratch files

[Randall Mackie]

xvec is a double precision complex vector that is dynamically allocated
once np is known. I've printed out the np value and it is correct.
This works on the first pass, but not the second.

This PETSc program has been working just fine for a couple years now,
the only difference this time is the size of the model I'm working
with, which is substantially larger than typical.

I'm going to try to run this in the debugger and see if I can get
anymore information.

Randy


Barry Smith wrote:
> 
>   Randy,
> 
>     The only "PETSc" related reason for this is that
> xvec(i), i=1,np is accessing out of range. What is xvec
> and is it of length 1 to np?
> 
>    Barry
> 
> 
> On Sat, 27 May 2006, Randall Mackie wrote:
> 
>> In my PETSc based modeling code, I write out intermediate results to a 
>> scratch
>> file, and then read them back later. This has worked fine up until today,
>> when for a large model, this seems to be causing my program to crash with
>> errors like:
>>
>> ------------------------------------------------------------------------
>> [9]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, 
>> probably memory access out of range
>>
>>
>> I've tracked down the offending code to:
>>
>>          IF (rank == 0) THEN
>>            irec=(iper-1)*2+ipol
>>            write(7,rec=irec) (xvec(i),i=1,np)
>>          END IF
>>
>> It writes out xvec for the first record, but then on the second
>> record my program is crashing.
>>
>> The record length (from an inquire statement) is  recl     22626552
>>
>> The size of the scratch file when my program crashes is 98M.
>>
>> PETSc is compiled using the intel compilers (v9.0 for fortran),
>> and the users manual says that you can have record lengths of
>> up to 2 billion bytes.
>>
>> I'm kind of stuck as to what might be the cause. Any ideas from anyone
>> would be greatly appreciated.
>>
>> Randy Mackie
>>
>> ps. I've tried both the optimized and debugging versions of the PETSc
>> libraries, with the same result.
>>
>>
>>
> 

-- 
Randall Mackie
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