Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "You'll note the use of mpi.cart.create(), which constructs a Cartesian rank/grid mapping from a group of existing MPI processes."

A block of code is set as follows:

Worker_makeSquareGrid <- function(comm,dim) {
  grid <- 1000 + dim    # assign comm handle for this size grid
  dims <- c(dim,dim)    # dimensions are 2D, size: dim X dim
  periods <- c(FALSE,FALSE)  # no wraparound at outermost edges 
  if (mpi.cart.create(commold=comm,dims,periods,commcart=grid))  
  {
    return(grid)
  }
  return(-1) # An MPI error occurred
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

# Namespace file for sprint 

useDynLib(sprint)

export(phello)
export(ptest)
export(pcor)

Any command-line input or output is written as follows:

$ mpicc -o mpihello.o mpihello.c 
$ mpiexec -n 4 ./mpihello.o

New terms and important words are shown in bold.