sum (expr, dexpr1, dexpr2, <,tinc> <,-b>)
Sums the result of expr
over the specified
dimension range. If the averaging dimension is time, an
optional time increment tincr
may be specified.
expr
- any valid GrADS expression dim1
- the start point for the sumdim2
- the end point for the sumtinc
- optional increment for time summing-b
- use exact boundaries
dim1
and dim2
are standard
GrADS dimension expressions whose dimensions must match.
dim1
and dim2
are specified in world coordinates, the
coordinates are converted to the nearest integer grid coordinates
based on the scaling of the default file. See the examples below for
further illustration.
-b
boundary flag is specified. The boundry flag indicates that the
sum should be taken to the exact boundaries specified by
dim1
and dim2
, rather than
the nearest grid points.
asum
function recognizes this and weights appropriately.
To calculate an sum without any weighting, use the sumg
function.