Sum of entries of a vector | F_SSUM/F_DSUM/F_CSUM/F_ZSUM | |
Name | F_SSUM/F_DSUM/F_CSUM/F_ZSUM | |
| Sum of entries of a vector | |
Purpose | F_xSUM computes the sum of the entries of a vector x. If n is less than or equal | |
| to zero, F_xSUM returns immediately with the output scalar r set to zero. | |
|
| n – 1 |
|
| r ← ∑ xi |
|
| i = 0 |
Usage | VECLIB: |
|
| INTEGER*4 | INCX, N |
| REAL*4 | X( * ) |
| REAL*4 | FUNCTION F_SSUM (N, X, INCX) |
| INTEGER*4 | INCX, N |
| REAL*8 | X( * ) |
| REAL*8 | FUNCTION F_DSUM (N, X, INCX) |
| INTEGER*4 | INCX, N |
| COMPLEX*8 | X( * ) |
| COMPLEX*8 | FUNCTION F_CSUM (N, X, INCX) |
| INTEGER*4 | INCX, N |
| COMPLEX*16 | X( * ) |
| COMPLEX*16 | FUNCTION F_ZSUM (N, X, INCX) |
| VECLIB8: |
|
| INTEGER*8 | INCX, N |
| REAL*4 | X( * ) |
| REAL*4 | FUNCTION F_SSUM (N, X, INCX) |
| INTEGER*8 | INCX, N |
| REAL*8 | X( * ) |
| REAL*8 | FUNCTION F_DSUM (N, X, INCX) |
| INTEGER*8 | INCX, N |
| COMPLEX*8 | X( * ) |
| COMPLEX*8 | FUNCTION F_CSUM (N, X, INCX) |
| INTEGER*8 | INCX, N |
| COMPLEX*16 | X( * ) |
| COMPLEX*16 | FUNCTION F_ZSUM (N, X, INCX) |
Input | N | Number of elements of vector x. |
Chapter 2 Basic Vector Operations 195