You could but you don’t need to. The datatype engine of Open MPI is doing a fair job of packing/unpacking the data on the flight, so you don’t have to.
George. > On Jan 16, 2015, at 11:32 , Diego Avesani <diego.aves...@gmail.com> wrote: > > Dear all, > > Could I use MPI_PACK? > > > Diego > > > On 16 January 2015 at 16:26, Diego Avesani <diego.aves...@gmail.com > <mailto:diego.aves...@gmail.com>> wrote: > Dear George, Dear all, > > I have been studying. It's clear for 2D case QQ(:,:). > > For example if > real :: QQ(npt,9) , with 9 the characteristic of each particles. > > I can simple: > > call MPI_TYPE_VECTOR(QQ(1:50), 9, 9, MPI_REAL, my_2D_type, ierr) > > I send 50 element of QQ. I am in fortran so a two dimensional array is > organized in a 1D array and a new row start after the 9 elements of a colum > > The problem is a 3D array. I belive that I have to create a sort of vector of > vectors. > More or less like: > > call MPI_TYPE_VECTOR(xxx, xxx, xxx, MPI_REAL, my_row, ierr) > > and then > > call MPI_TYPE_VECTOR(xxx, xxx, xxx, my_row, my_type, ierr). > > You can note that in the second case I have my_row instead of mpi_real. > > I found somethind about it in a tutorial but I am not able to find it again > in google. I think that is not convinient the use of struct in this case, I > have only real. Moreover, mpi_struct is think to emulate Fortran90 and C > structures, as Gus' suggestion. > > Let's me look to that tutorial > What do you think? > > Thanks again > > > > > > > Diego > > > On 16 January 2015 at 16:02, George Bosilca <bosi...@icl.utk.edu > <mailto:bosi...@icl.utk.edu>> wrote: > 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 > <mailto: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 > <mailto: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 > > <mailto: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_vector.3.php> > > http://www.open-mpi.org/doc/v1.8/man3/MPI_Type_create_subarray.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 > > <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 > > <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> > >> <mailto: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> > >>> <mailto: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> > >>> <mailto: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-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> > >>> <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> > >>> <mailto: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> > >>> <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> > >>> > >>> <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> > >>> <mailto: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> > >>> <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> > >>> <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> > >>> <mailto: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/2015/01/26184.php > >>> <http://www.open-mpi.org/community/lists/users/2015/01/26184.php> > >> > >> > >> _______________________________________________ > >> users mailing list > >> us...@open-mpi.org <mailto:us...@open-mpi.org> > >> <mailto: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/2015/01/26192.php > >> <http://www.open-mpi.org/community/lists/users/2015/01/26192.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/2015/01/26193.php > >> <http://www.open-mpi.org/community/lists/users/2015/01/26193.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/2015/01/26194.php > > <http://www.open-mpi.org/community/lists/users/2015/01/26194.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/2015/01/26195.php > <http://www.open-mpi.org/community/lists/users/2015/01/26195.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/2015/01/26197.php > <http://www.open-mpi.org/community/lists/users/2015/01/26197.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/2015/01/26199.php > <http://www.open-mpi.org/community/lists/users/2015/01/26199.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/2015/01/26201.php > <http://www.open-mpi.org/community/lists/users/2015/01/26201.php>
