d2/d74/zscal_8f_source.html

00001       SUBROUTINE ZSCAL(N,ZA,ZX,INCX)
00002 *     .. Scalar Arguments ..
00003       DOUBLE COMPLEX ZA
00004       INTEGER INCX,N
00005 *     ..
00006 *     .. Array Arguments ..
00007       DOUBLE COMPLEX ZX(*)
00008 *     ..
00009 *
00010 *  Purpose
00011 *  =======
00012 *
00013 *     ZSCAL scales a vector by a constant.
00014 *
00015 *  Further Details
00016 *  ===============
00017 *
00018 *     jack dongarra, 3/11/78.
00019 *     modified 3/93 to return if incx .le. 0.
00020 *     modified 12/3/93, array(1) declarations changed to array(*)
00021 *
00022 *  =====================================================================
00023 *
00024 *     .. Local Scalars ..
00025       INTEGER I,IX
00026 *     ..
00027       IF (N.LE.0 .OR. INCX.LE.0) RETURN
00028       IF (INCX.EQ.1) GO TO 20
00029 *
00030 *        code for increment not equal to 1
00031 *
00032       IX = 1
00033       DO 10 I = 1,N
00034           ZX(IX) = ZA*ZX(IX)
00035           IX = IX + INCX
00036    10 CONTINUE
00037       RETURN
00038 *
00039 *        code for increment equal to 1
00040 *
00041    20 DO 30 I = 1,N
00042           ZX(I) = ZA*ZX(I)
00043    30 CONTINUE
00044       RETURN
00045       END