The operation you describe is a pack operation, agglomerating together in a contiguous buffer originally discontinuous elements. As a result there is no need to use the MPI_TYPE_VECTOR, but instead you can just use the type you created so far (MPI_my_STRUCT) with a count.
George. On Fri, Jan 16, 2015 at 5:32 AM, Diego Avesani <diego.aves...@gmail.com> wrote: > Dear All, > I'm sorry to insist, but I am not able to understand. Moreover, I have > realized that I have to explain myself better. > > I try to explain in may program. Each CPU has *npt* particles. My program > understand how many particles each CPU has to send, according to their > positions. Then I can do: > > *icount=1* > * DO i=1,npt* > * IF(i is a particle to send)THEN* > > * DATASEND(icount)%ip = PART(ip)%ip* > * DATASEND(icount)%mc = PART(ip)%mc* > > * DATASEND(icount)%RP = PART(ip)%RP* > * DATASEND(icount)%QQ = PART(ip)%QQ* > > * icount=icount+1* > * ENDIF* > * ENDDO* > > After that, I can send *DATASEND* > > I *DATASEND* is a *MPI_my_STRUCT.* I can allocate it according to > the number of particles that I have to send: > > TYPE(tParticle) ,ALLOCATABLE,DIMENSION(:) :: DATASEND,DATARECV > > This means that the number of particles which I have to send can change > every time. > > After that, I compute for each particles, somethins called QQmls(:,:,:). > QQmls has all real elements. Now I would like to to the same that I did > with PART, but in this case: > > *icount=1* > *DO i=1,npt* > * IF(i is a particle to send)THEN* > > *DATASEND_REAL(:,icount,:)=QQmls(:,i,:)* > * icount=icount+1* > > * ENDIF* > *ENDDO* > > I would like to have a sort *MPI_my_TYPE to do that (like * > *MPI_my_STRUCT**) *and not to create every time *MPI_TYPE_VECTOR *because > *DATASEND_REAL *changes size every time. > > I hope to make myself clear. > > So is it correct to use *MPI_TYPE_VECTOR?, *Can I do what I want? > > In the meantime, I will study some examples. > > Thanks again > > > > > > Diego > > > On 16 January 2015 at 07:39, George Bosilca <bosi...@icl.utk.edu> wrote: > >> The subarray creation is an multi-dimension extension of the vector >> type. You can see it as a vector of vector of vector and so on, one vector >> per dimension. The stride array is used to declare on each dimension what >> is the relative displacement (in number of elements) from the beginning of >> the dimension array. >> >> It is important to use regular type creation when you can take advantage >> of such regularity instead of resorting to use of struct or h*. This insure >> better packing/unpacking performance, as well as possible future support >> for one-sided communications. >> >> George. >> >> >> >> > On Jan 15, 2015, at 19:31, Gus Correa <g...@ldeo.columbia.edu> wrote: >> > >> > I never used MPI_Type_create_subarray, only MPI_Type_Vector. >> > What I like about MPI_Type_Vector is that you can define a stride, >> > hence you can address any regular pattern in memory. >> > However, it envisages the array layout in memory as a big 1-D array, >> > with a linear index progressing in either Fortran or C order. >> > >> > Somebody correct me please if I am wrong, but at first sight >> MPI_Type_Vector sounds more flexible to me than MPI_Type_create_subarray, >> exactly because the latter doesn't have strides. >> > >> > The downside is that you need to do some index arithmetic to figure >> > the right strides, etc, to match the corresponding >> > Fortran90 array sections. >> > >> > There are good examples in the "MPI - The complete reference" books I >> suggested to you before (actually in vol 1). >> > >> > Online I could find the two man pages (good information, but no >> example): >> > >> > http://www.open-mpi.org/doc/v1.8/man3/MPI_Type_vector.3.php >> > http://www.open-mpi.org/doc/v1.8/man3/MPI_Type_create_subarray.3.php >> > >> > There is a very simple 2D example of MPI_Type_vector using strides here: >> > >> > https://computing.llnl.gov/tutorials/mpi/#Derived_Data_Types >> > >> > and a similar one here: >> > >> > http://static.msi.umn.edu/tutorial/scicomp/general/MPI/content6.html >> > >> > Gus Correa >> > >> >> On 01/15/2015 06:53 PM, Diego Avesani wrote: >> >> dear George, dear Gus, dear all, >> >> Could you please tell me where I can find a good example? >> >> I am sorry but I can not understand the 3D array. >> >> >> >> >> >> Really Thanks >> >> >> >> Diego >> >> >> >> >> >> On 15 January 2015 at 20:13, George Bosilca <bosi...@icl.utk.edu >> >> <mailto:bosi...@icl.utk.edu>> wrote: >> >> >> >> >> >>> On Jan 15, 2015, at 06:02 , Diego Avesani <diego.aves...@gmail.com >> >>> <mailto:diego.aves...@gmail.com>> wrote: >> >>> >> >>> Dear Gus, Dear all, >> >>> Thanks a lot. >> >>> MPI_Type_Struct works well for the first part of my problem, so I >> >>> am very happy to be able to use it. >> >>> >> >>> Regarding MPI_TYPE_VECTOR. >> >>> >> >>> I have studied it and for simple case it is clear to me what id >> >>> does (at least I believe). Foe example if I have a matrix define >> as: >> >>> REAL, ALLOCATABLE (AA(:,:)) >> >>> ALLOCATE AA(100,5) >> >>> >> >>> I could send part of it defining >> >>> >> >>> CALL MPI_TYPE_VECTOR(5,1,5,MPI_DOUBLE_PRECISION,/MY_NEW_TYPE/) >> >>> >> >>> after that I can send part of it with >> >>> >> >>> CALL MPI_SEND( AA(1:/10/,:), /10/, /MY_NEW_TYPE/, 1, 0, >> >>> MPI_COMM_WORLD ); >> >>> >> >>> Have I understood correctly? >> >>> >> >>> What I can do in case of three dimensional array? for example >> >>> AA(:,:,:), I am looking to MPI_TYPE_CREATE_SUBARRAY. >> >>> Is that the correct way? >> >>> >> >>> Thanks again >> >> >> >> Indeed, using the subarray is the right approach independent on the >> >> number of dimensions of the data (you can use it instead of >> >> MPI_TYPE_VECTOR as well). >> >> >> >> George. >> >> >> >> >> >>> >> >>> >> >>> >> >>> >> >>> Diego >> >>> >> >>> >> >>> On 13 January 2015 at 19:04, Gus Correa <g...@ldeo.columbia.edu >> >>> <mailto:g...@ldeo.columbia.edu>> wrote: >> >>> >> >>> Hi Diego >> >>> I guess MPI_Type_Vector is the natural way to send and receive >> >>> Fortran90 array sections (e.g. your QQMLS(:,50:100,:)). >> >>> I used that before and it works just fine. >> >>> I think that is pretty standard MPI programming style. >> >>> I guess MPI_Type_Struct tries to emulate Fortran90 and C >> >>> structures >> >>> (as you did in your previous code, with all the surprises >> >>> regarding alignment, etc), not array sections. >> >>> Also, MPI type vector should be more easy going (and probably >> >>> more efficient) than MPI type struct, with less memory >> >>> alignment problems. >> >>> I hope this helps, >> >>> Gus Correa >> >>> >> >>> PS - These books have a quite complete description and several >> >>> examples >> >>> of all MPI objects and functions, including MPI types (native >> >>> and user defined): >> >>> http://mitpress.mit.edu/books/__mpi-complete-reference-0 >> >>> <http://mitpress.mit.edu/books/mpi-complete-reference-0> >> >>> http://mitpress.mit.edu/books/__mpi-complete-reference-1 >> >>> <http://mitpress.mit.edu/books/mpi-complete-reference-1> >> >>> >> >>> [They cover MPI 1 and 2. I guess there is a new/upcoming book >> >>> with MPI 3, but for what you're doing 1 and 2 are more than >> >>> enough.] >> >>> >> >>> >> >>> On 01/13/2015 09:22 AM, Diego Avesani wrote: >> >>> >> >>> Dear all, >> >>> >> >>> I had some wonderful talking about MPI_type_create_struct >> adn >> >>> isend\irecv with >> >>> Gilles, Gustavo, George, Gus, Tom and Jeff. Now all is >> >>> more clear and my >> >>> program works. >> >>> >> >>> Now I have another question. In may program I have matrix: >> >>> >> >>> /QQMLS(:,:,:) /that is allocate as >> >>> >> >>> /ALLOCATE(QQMLS(9,npt,18)/), where npt is the number of >> >>> particles >> >>> >> >>> QQMLS is double precision. >> >>> >> >>> I would like to sent form a CPU to another part of it, for >> >>> example, >> >>> sending QQMLS(:,50:100,:). I mean sending the QQMLS of the >> >>> particles >> >>> between 50 to 100. >> >>> I suppose that i could use MPI_Type_vector but I am not >> >>> sure. The >> >>> particle that I want to sent could be from 25 to 50 ecc.. >> >>> ecc..so >> >>> blocklength changes everytime. >> >>> >> >>> Do I have to use MPI_type_create_struct? >> >>> Do I have correctly understood MPI_Type_vector? >> >>> >> >>> Thanks a lot >> >>> >> >>> >> >>> Diego >> >>> >> >>> >> >>> >> >>> _________________________________________________ >> >>> users mailing list >> >>> us...@open-mpi.org <mailto:us...@open-mpi.org> >> >>> Subscription: >> >>> http://www.open-mpi.org/__mailman/listinfo.cgi/users >> >>> <http://www.open-mpi.org/mailman/listinfo.cgi/users> >> >>> Link to this post: >> >>> >> http://www.open-mpi.org/__community/lists/users/2015/01/__26171.php >> >>> < >> http://www.open-mpi.org/community/lists/users/2015/01/26171.php> >> >>> >> >>> >> >>> _________________________________________________ >> >>> users mailing list >> >>> us...@open-mpi.org <mailto:us...@open-mpi.org> >> >>> Subscription: >> >>> http://www.open-mpi.org/__mailman/listinfo.cgi/users >> >>> <http://www.open-mpi.org/mailman/listinfo.cgi/users> >> >>> Link to this post: >> >>> >> http://www.open-mpi.org/__community/lists/users/2015/01/__26172.php >> >>> < >> http://www.open-mpi.org/community/lists/users/2015/01/26172.php> >> >>> >> >>> >> >>> _______________________________________________ >> >>> users mailing list >> >>> us...@open-mpi.org <mailto:us...@open-mpi.org> >> >>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> >>> Link to this post: >> >>> http://www.open-mpi.org/community/lists/users/2015/01/26184.php >> >> >> >> >> >> _______________________________________________ >> >> users mailing list >> >> us...@open-mpi.org <mailto:us...@open-mpi.org> >> >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> >> Link to this post: >> >> http://www.open-mpi.org/community/lists/users/2015/01/26192.php >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> >> users mailing list >> >> us...@open-mpi.org >> >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2015/01/26193.php >> > >> > _______________________________________________ >> > users mailing list >> > us...@open-mpi.org >> > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> > Link to this post: >> http://www.open-mpi.org/community/lists/users/2015/01/26194.php >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2015/01/26195.php >> > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/01/26197.php >
