Errata for `Using MPI, 2nd Edition'

p xvii
The third line from the bottom should be ``MPICH. Appendix C''.
Thanks to Bryan Putnam <bfp@purdue.edu>.

p 6
The 5th line from the bottom has an extra ``the'' in it; the end of that line should be ``not the same''.


Thanks to Bryan Putnam <bfp@purdue.edu>.

p 12
The last sentance should end in a more tutorial approach in [66].


Thanks to Bryan Putnam <bfp@purdue.edu>.

p 42
The 5th line from the top reads 
    if (rank .gt. rows)
but should read 
    if (myid .gt. rows)
Thanks to Weiqun Zhang <zhang@ucolick.org>.

p 48
The declaration of ans should use MAX_BCOLS: 
      double precision buffer(MAX_ACOLS), ans(MAX_ACOLS)
should be 
      double precision buffer(MAX_ACOLS), ans(MAX_BCOLS)
Thanks to Bryan Putnam <bfp@purdue.edu>.

p 48--51
The example code here uses user-defined state numbers in the MPE logging calls (e.g., MPE_DESCRIBE_STATE). While this works with stand-alone logging, it is not compatible with the automatic logging that is available with MPICH. Applications should consider using the routine MPE_Log_get_event_number to get state numbers rather than defining them.


Thanks to Anthony Chan <chan@mcs.anl.gov>.

p 48--51
There are a few errors in the examples in Figures 3.10, 3.11, and 3.12. In Figure 3.10, the variable master should be initialized to zero.

If Figure 3.12, all of the calls to MPI_LOG_EVENT need an additional argument IERR at the end of the argument list; i.e., 

         call MPE_LOG_EVENT(2, 0, "bend", ierr)
Note that laster versions of the Fortran MPE routines return the error code as the value of the function, and hence would nee 
         ierr = MPE_LOG_EVENT( 2, 0, "bsend" )
In Figure 3.11 on page 50, the call to MPI_BCAST is not shown in the code. The call is referred to at the line 
         .... initialization of a and b, broadcast of b
but the code itself is not shown. It is the same as in Figure 3.12: 
         do 85 i = 1,bcols 
         call MPI_BCAST(b(1,i), brows, MPI_DOUBLE_PRECISION, master, & 
                        MPI_COMM_WORLD, ierr) 
 85      continue

Thanks to Hartmut Kapitza <hartmut.kapitza@gkss.de>.

p 57
The value of INT_MAX must correspond to the range used by the random routine. Linux users can use RAND_MAX; for greatest portability, values returned from random should be discarded if they are too large. The following code replaces the code in the master for filling the rands array: 
            if (request) { 
                for (i = 0; i < CHUNKSIZE; ) { 
                        rands[i] = random(); 
                        if (rands[i] <= INT_MAX) i++; 
                }
Thanks to Kevin T. Pedretti <pedretti@eng.uiowa.edu>.

p 58
The call to MPI_Comm_free should be moved into the worker process branch of the if. Thanks to Kevin T. Pedretti <pedretti@eng.uiowa.edu>.

p 64
In the second paragraph from the bottom, ``some compilers'' should be ``Some compilers''.

p 65
In the second item (Expecting argc etc.), ``this allows'' should be ``This allows''.

p 65
The last line of this page reads ``broadcast than hence'' but should read ``broadcast and hence''

Thanks to Dan Negrut.

p 72
The code in Figure 4.2 has a misplaced parenthesis and should be 
      integer i, j, n 
      double precision u(0:n+1,0:n+1), unew(0:n+1,0:n+1) 
      do 10 j=1, n 
         do 10 i=1, n 
            unew(i,j) = & 
                0.25*(u(i-1,j)+u(i,j+1)+u(i,j-1)+u(i+1,j) - & 
                h * h * f(i,j)) 
 10   continue
Thanks to Steven Knudsen <sknudsen@softwareresearch.org>.

p 85
The seventh line from the bottom reads ``... the matching receives are take place...'' but should read ``... the matching receives take place...'' (remove the ``are'')

Thanks to Dan Negrut.

p 97
The legend for Figure 4.17 should say Predicted time for a 1-D (solid) and 2-D (dashed) decomposition of the 2-D Poisson problem Thanks to Paul Hovland <hovland@mcs.anl.gov>.

p 99
The near the bottom of the page has a misplaced parenthesis and should be 
    integer i, j, n 
    double precision u(sx-1:ex+1,sy-1:ey+1), & 
                     unew(sx-1:ex+1,sy-1:ey+1) 
    do 10 j=sy+1, ey-1 
       do 10 i=sx+1, ex-1 
          unew(i,j) = & 
                0.25*(u(i-1,j)+u(i,j+1)+u(i,j-1)+u(i+1,j) - & 
                   h * h * f(i,j)) 
 10 continue
p 100
The first argument to the MPI_TYPE_VECTOR call in the middle of the page should be ey-sy+1 since only the interior points of the mesh are communicated. The text in the last full paragraph on the page should read ... In this example, there is one double-precision item per block; the double-precision values are ex + 1 - (sx - 1) + 1 = ex - sx + 3 apart, and there are ey - (sy) + 1 = ey - sy + 1 of them, since only the interior elements are needed. ...

p 100
The sentance after the call MPI_TYPE_COMMIT should read The arguments to MPI_Type_vector describe a block, which consists of a number of (contiguous) copies of the input datatype given by the fourth argument. The first argument is the number of blocks; the second is the number The final two sentences of this paragraph should read In this example, there is one double-precision item per block; the double-precision values are ex + 1 - (sx - 1) + 1 = ex - sx + 3 apart, and there are ey - sy + 1 = ey - sy + 1 of them. Figure 4.19 illustrates an MPI vector datatype. Thanks to Hartmut Kapitza <hartmut.kapitza@gkss.de>.

p 104
The code in Figure 4.22 has a misplaced parenthesis and should be 
    integer i, j, n 
    double precision u(sx-1:ex+1,sy-1:ey+1), & 
                     unew(sx-1:ex+1,sy-1:ey+1) 
    do 10 j=sy+1, ey-1 
       do 10 i=sx+1, ex-1 
          unew(i,j) = & 
                0.25*(u(i-1,j)+u(i,j+1)+u(i,j-1)+u(i+1,j) - & 
                   h * h * f(i,j)) 
 10 continue

p 105
The computed goto in the example should refer to status(MPI_TAG), not status(MPI_TAG,idx), since for MPI_Waitany, only a single status value is returned. However, because 4 of the requests are sends instead of receives, it would be better to use the idx value returned by MPI_Waitany; this indicates which request has completed. A cleaner solution moves the wait on the sends to a separate step, using MPI_Waitall for them (this uses the MPI-2 MPI_STATUSES_IGNORE to simplify the Waitall call): 


do 100 k=1, 4 
    call MPI_WAITANY(4,requests,idx,status,ierr) 
    goto (1,2,3,4), idx 
    ... 
enddo 
call MPI_WAITALL(4, requests(4), MPI_STATUSES_IGNORE, ierr)

Thanks to jose@frenadol.ti.uam.es.

p 114
''descuss'' should be ``discuss'' in the first line of the page


Thanks to Rusty Lusk <lusk@mcs.anl.gov>.

p 121
In the second example using MPI_Allgather, counts should be totalcount, where totalcount is the sum of the values in the array counts: 
    MPI_Allgather( myparticles, count, particletype,  
               allparticles, totalcount, particletype, MPI_COMM_WORLD );
Thanks to Dinesh Kaushik <kaushik@mcs.anl.gov>.

p 123
Not actually an errata, but a clarification. After the example at the end of section 5.2.1, add a paragraph that explains why there are MPI datatypes for both the sender and receiver, particularly for MPI_Gather and MPI_Allgather. In case you are wondering, the reason is that MPI requires only that the type signatures match; for example, by using a different MPI datatype for the send and receive types, the data can be transposed ``on the fly''. For example, the send type could specify a row of a matrix (stored in column-major, with n columns) with a sendcount of 1 and the receive type could specify contiguous doubles with a receive count of n and receive type of MPI_DOUBLE.

p 124
Line 10 reads 
    MPI_Start( request );
but should read 
    MPI_Start( &request );
Thanks to Barry Smith <bsmith@mcs.anl.gov>.

p 144
The end of the first line of the last paragraph and the beginning of the second line reads ``describe as a single datatype as a collection'' but should read ``describe with a single datatype a collection''

Thanks to Dan Negrut.

p152
The end of the first line and the begining of the second reads ``we can see hot to make the create'' but should read ``we can see how to create''

Thanks to Dan Negrut.

p 155
The second line from the bottom is missing a close parenthesis

Thanks to Rusty Lusk <lusk@mcs.anl.gov>.

p 158
In the 2nd paragraph from the bottom, ``particular master/worker'' should be ``particularly master/worker''

p 167
The bindings for the MPI_Copy_function and the MPI_Delete_function should not use pointers to the communicators. This was a change from MPI 1.0 to MPI 1.1. The correct code is

MPI_Copy_functionMPI_Comm oldcomm, int *keyval, void *extra_state, void *attribute_value_in, void *attribute_value_out, int *flagtypedef int MPI_Delete_functionMPI_Comm comm, int *keyval, void *attribute_value, void *extra_statetypedef int

Thanks to Emil Ong <onge@mcs.anl.gov>.

p 221
The remote leader was not correctly set in this example. The correct code is given below (the changes are the lines that include remote_leader 
    program main 
    use mpi 
    integer ocean_or_atmos_comm, intercomm, ocean_comm, atmos_comm 
    integer nprocs, rank, ierr, color, remote_leader 
    integer OCEAN, ATMOS 
    parameter (OCEAN=0,ATMOS=1) 
 
    call MPI_INIT( ierr ) 
    call MPI_COMM_SIZE( MPI_COMM_WORLD, nprocs, ierr ) 
    call MPI_COMM_RANK( MPI_COMM_WORLD, rank, ierr ) 
    if (rank .lt. size/2) then 
        color = OCEAN 
        remote_leader = size/2 
    else 
        color = ATMOS 
        remote_leader = 0 
    endif 
    call MPI_COMM_SPLIT( MPI_COMM_WORLD, color, rank, & 
                         ocean_or_atmos_comm, ierr ) 
    call MPI_INTERCOMM_CREATE( ocean_or_atmos_comm, 0, & 
                         MPI_COMM_WORLD, remote_leader, & 
                         0, intercomm, ierr ) 
    if (color .eq. OCEAN) then 
        ocean_comm = ocean_or_atmos_comm 
        call do_ocean( ocean_comm ) 
    else 
        atmos_comm = ocean_or_atmos_comm 
        call do_atmos( atmos_comm ) 
    endif 
    call ocean_and_atmos( intercomm ) 
    ... 
    end
Thanks to Richard Rogers <rrogers@mediosystems.com>.

p 233--268
The following typographic errors were found by Jeffrey Oldham <oldham@codesourcery.com>:

p 237
''stop code)'' should be ``stop(code))''. Thanks to Rusty Lusk <lusk@mcs.anl.gov>.

p 240
``gloabl'' should be ``global'' in the last line.

p 268
In Section 9.2.2, ``rather is combines'' should be ``rather it combines''

p 270
At the top of the page, add a comma after the section number ``in Section 5.2.5,''

p 349
In Appendix E, there are two errors. In the middle of the page, To see this, remember that the formula for the locations of the elements of a(i,j,k) is offset + (i-1) + nx * ((j-1) + ny * (z-1)). should be To see this, remember that the formula for the locations of the elements of a(i,j,k) is offset + (i-1) + nx * ((j-1) + ny * (k-1)). (the z-1 should be k-1). At the bottom of the page, 
    call MPI_TYPE_VECTOR( ny * nz, 1, nx * ny, & 
                          MPI_DOUBLE_PRECISION, newx, ierror )
should be 
    call MPI_TYPE_VECTOR( ny * nz, 1, nx, & 
                          MPI_DOUBLE_PRECISION, newx, ierror )
Thanks to Mehdi Bostandoost <smb51+@pitt.edu>.