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Date: Thu, 20 Sep 2001 17:33:45 +0200
From: Peter Ganster <P.Ganster@XXXXXXXXXXXX>
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To: William Gropp <gropp@XXXXXXXXXXX>
Subject: Re: blocklength zero in MPI_Type_struct
References: <5.1.0.14.2.20010920101208.04ac63d0@XXXXXXXXX>
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William Gropp wrote:
> 
> At 01:16 PM 7/25/2001 +0200, Peter Ganster wrote:
> >Hello,
> >
> >I have a question:
> >
> >What happens if one use blocklenghts of zero in the call of
> >MPI_Type_struct: Is the behavior implementation dependent or is it
> >definded by the MPI-1 or MPI-2 standard?
> 
> The standard seems to allow this.  Interestingly enough, other Datatype
> routines are careful to specify that the values in the array of
> blocklengths are non-negative rather than positive (see
> MPI_TYPE_HINDEXED).  This is strengthed by the comment at the end of 3.12.1
> that states that a call to MPI_TYPE_HINDEXED is equivalent to a call to
> MPI_TYPE_STRUCT where all of the datatypes are of the same type, suggesting
> that since zero blocklenghts are allowed in MPI_TYPE_HINDEXED, they must be
> in MPI_TYPE_STRUCT.
> 
> Bill

Hello Bill,
thank you for the answer.

Peter