[MPICH] question about MPI-IO Read_all

[Wei-keng Liao]

Yes, if the hindexed datatype "describes" the entire amount of data you 
want to write, count is 1. In general, one can also use count=2, 3... 
That will just write multiple of hindexed datatypes from the I/O buffer.

Wei-keng

On Thu, 26 Apr 2007, Russell L. Carter wrote:

> Ok, very good Wei-keng, one more question.  This is exactly
> what I wanted to know, thanks for addressing it.
>
> Wei-keng Liao wrote:
>
> [...]
>> The data amount to be read/written by an MPI process in a 
>> Read_all()/Write_all() is the "count" multiplies the size of the buffer 
>> datatype. Therefore, the read/write amount can still be larger than 2GB 
>> when integer "count" is less than 2^32. Note that the data amount one can 
>> read/write is determined by these two arguments, not the fileview.
>> Hope this helps.
>
> So if I use say an hindexed datatype for the Read_all, is the count just
> '1'?
>
> Thanks,
> Russell
>
>> Wei-keng
>> 
>> 
>> 
>