12.5.1 Calculating row boundaries on processors

The number of processors is read in through namelist as variable $num\_processors$. The model domain is divided into $num\_processors$pieces with each piece containing the same number^12.5 of latitude rows. Each processor is assigned the task of working on its own piece of the domain starting with latitude index jrow=jstask and ending with latitude index jrow=jetask. Each processor has its own memory window to process only those latitude rows within its own task. The starting and ending rows of each processor's task are given by

$$nint((pn-1)*calculated\_rows) + (2-jbuf)$$ jstask = (12.1)

$$nint(pn*calculated\_rows) + (1+jbuf)$$ jetask = (12.2)

where pn is the processor number ( $pn=1\cdots\;num\_processors$), the number of buffer rows ``jbuf'' is explained in Section 11.3.1, and

$$calculated\_rows = float(jmt-2)/num\_processors.$$ (12.3)

The latitude rows for which the tracer and baroclinic equations are solved within the processor's task are controlled by the starting and stopping rows

jscomp = jstask + jbuf (12.4)

jecomp = jetask - jbuf (12.5)