root / src / blas / icamax.f @ 8
Historique | Voir | Annoter | Télécharger (1,16 ko)
| 1 |
INTEGER FUNCTION ICAMAX(N,CX,INCX) |
|---|---|
| 2 |
* .. Scalar Arguments .. |
| 3 |
INTEGER INCX,N |
| 4 |
* .. |
| 5 |
* .. Array Arguments .. |
| 6 |
COMPLEX CX(*) |
| 7 |
* .. |
| 8 |
* |
| 9 |
* Purpose |
| 10 |
* ======= |
| 11 |
* |
| 12 |
* finds the index of element having max. absolute value. |
| 13 |
* jack dongarra, linpack, 3/11/78. |
| 14 |
* modified 3/93 to return if incx .le. 0. |
| 15 |
* modified 12/3/93, array(1) declarations changed to array(*) |
| 16 |
* |
| 17 |
* |
| 18 |
* .. Local Scalars .. |
| 19 |
REAL SMAX |
| 20 |
INTEGER I,IX |
| 21 |
* .. |
| 22 |
* .. External Functions .. |
| 23 |
REAL SCABS1 |
| 24 |
EXTERNAL SCABS1 |
| 25 |
* .. |
| 26 |
ICAMAX = 0 |
| 27 |
IF (N.LT.1 .OR. INCX.LE.0) RETURN |
| 28 |
ICAMAX = 1 |
| 29 |
IF (N.EQ.1) RETURN |
| 30 |
IF (INCX.EQ.1) GO TO 20 |
| 31 |
* |
| 32 |
* code for increment not equal to 1 |
| 33 |
* |
| 34 |
IX = 1 |
| 35 |
SMAX = SCABS1(CX(1)) |
| 36 |
IX = IX + INCX |
| 37 |
DO 10 I = 2,N |
| 38 |
IF (SCABS1(CX(IX)).LE.SMAX) GO TO 5 |
| 39 |
ICAMAX = I |
| 40 |
SMAX = SCABS1(CX(IX)) |
| 41 |
5 IX = IX + INCX |
| 42 |
10 CONTINUE |
| 43 |
RETURN |
| 44 |
* |
| 45 |
* code for increment equal to 1 |
| 46 |
* |
| 47 |
20 SMAX = SCABS1(CX(1)) |
| 48 |
DO 30 I = 2,N |
| 49 |
IF (SCABS1(CX(I)).LE.SMAX) GO TO 30 |
| 50 |
ICAMAX = I |
| 51 |
SMAX = SCABS1(CX(I)) |
| 52 |
30 CONTINUE |
| 53 |
RETURN |
| 54 |
END |