[mpich-discuss] How to fix Invalid arguments during creation of MPI derived Datatypes

[Rajeev Thakur]

How are you filling the blockcounts and offsets arrays? Have you declared offsets as MPI_Aint * ?


On Jan 24, 2012, at 4:29 AM, Gopal Rastogi wrote:

>     I have one `structure xyz` as given below and i need 
> to broadcast it among 20 nodes. so i used `MPI_Bcast()` function 
> to do this. This function requires MPI datatype of corresponding 
> structure xyz type as third arguments.
> `struct xyz
> {
>  char a;
>  int32_t b;
>  char c[50];
>  uint32_t d;
>  uchar e[10];
> }`
> 
> So i used `MPI_Type_creat_struct()` function to create a new MPI datatype 
> as `MPI_Datatype MPI_my_new_datatype, oldtypes[4];`
>  where i used MPI datatypes corresponding to above structure members datatype 
> as followings
>  `oldtypes[4] = {MPI_CHAR, MPI_INT, MPI_UNSIGNED, MPI_UNSIGNED_CHAR};` 
> 
> and to craete new datatype i used following arguments in the function..
>     MPI_Type_create_struct(4, blockcounts, offsets, oldtypes, &MPI_my_new_datatype);
>     MPI_Type_commit(&MPI_my_new_datatype);
> Now it is compiling but giving run time error as below::
> 
> *** An error occurred in `MPI_Type_create_struct`on 
> communicator `MPI_COMM_WORLD` 
> `MPI_ERR_ARG`: invalid argument of some other kind 
> `MPI_ERRORS_ARE_FATAL` (goodbye).
> 
> Can any one find out where is the problem?
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