SUM(3I) Last changed: 1-6-98
NAMESUM - Sums array elements
SYNOPSISSUM ([ARRAY=]array [,[DIM=]dim] [,[MASK=]mask])
SUM ([ARRAY=]array [,[MASK=]mask])
IMPLEMENTATION
UNICOS, UNICOS/mk, and IRIX systems
STANDARDS
Fortran 90
DESCRIPTION
The SUM intrinsic function sums all the elements of array along
dimension dim that correspond to the true elements of mask. It
accepts the following arguments:
array Must be of type integer, real, or complex. It must not be
scalar.
dim Must be scalar and of type integer with a value in the range
1 <= dim <= n, where n is the rank of array. The
corresponding actual argument must not be an optional dummy
argument. This function does a check on dim when present.
mask Must be of type logical and must be conformable with array.
SUM is a transformational intrinsic function. The name of this
intrinsic cannot be passed as an argument.
RETURN VALUES
The result is of the same type and kind type parameter as array. It
is scalar if dim is absent or if array has rank one; otherwise, the
result is an array of rank n-1 and of shape
(d , d , ..., d , d , ..., d ),
1 2 dim-1 dim+1 n
where (d , d , ..., d )
1 2 n
is the shape of array.
The result of SUM(array) has a value equal to the sum of all the
elements of array. If array has size 0, it has the value 0.
The result of SUM(array,MASK=mask) has a value equal to the sum of the
elements of array corresponding to the true elements of mask. It has
the value 0 if there are no true elements.
If array has rank one, SUM(array,dim[,mask]) has a value equal to that
of SUM(array[,MASK=mask]). Otherwise, the value of element
(s , s , ..., s , s , ..., s )
1 2 dim-1 dim+1 n
of SUM(array,dim[,mask]) is equal to
SUM(array(s , s , ..., s , : , s , ..., s )
1 2 dim-1 dim+1 n
[, MASK=mask(s , s , ..., s , : , s , ..., s )]).
1 2 dim-1 dim+1 n
EXAMPLES
Example 1: The value of SUM((/ 1, 2, 3 /)) is 6.
Example 2: SUM(C, MASK= C .GT. 0.0) forms the arithmetic sum of the
positive elements of C.
Example 3: Assume that B is the following array:
| 1 3 5 |
| 2 4 6 |
In this case, the following are true:
* SUM(B, DIM = 1) is [3, 7, 11]
* SUM(B, DIM = 2) is [9, 12]
SEE ALSO
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
