SCALAPACK 2.2.2
LAPACK: Linear Algebra PACKage
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sset.f
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1 SUBROUTINE sset( N, ALPHA, X, INCX )
2*
3* -- PBLAS auxiliary routine (version 2.0) --
4* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
5* and University of California, Berkeley.
6* April 1, 1998
7*
8* .. Scalar Arguments ..
9 INTEGER INCX, N
10 REAL ALPHA
11* ..
12* .. Array Arguments ..
13 REAL X( * )
14* ..
15*
16* Purpose
17* =======
18*
19* SSET sets the entries of an n vector x to the scalar alpha.
20*
21* Arguments
22* =========
23*
24* N (input) INTEGER
25* On entry, N specifies the length of the vector x. N must be
26* at least zero.
27*
28* ALPHA (input) REAL
29* On entry, ALPHA specifies the scalar alpha.
30*
31* X (input/output) REAL array of dimension at least
32* ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented
33* array X must contain the vector x. On exit, entries of the
34* incremented array X are set to alpha.
35*
36* INCX (input) INTEGER
37* On entry, INCX specifies the increment for the elements of X.
38* INCX must not be zero.
39*
40* -- Written on April 1, 1998 by
41* Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
42*
43* =====================================================================
44*
45* .. Local Scalars ..
46 INTEGER I, INFO, IX, M, MP1
47* ..
48* .. External Subroutines ..
49 EXTERNAL xerbla
50* ..
51* .. Intrinsic Functions ..
52 INTRINSIC mod
53* ..
54* .. Executable Statements ..
55*
56* Test the input parameters.
57*
58 info = 0
59 IF( n.LT.0 ) THEN
60 info = 1
61 ELSE IF( incx.EQ.0 ) THEN
62 info = 4
63 END IF
64 IF( info.NE.0 ) THEN
65 CALL xerbla( 'SSET', info )
66 RETURN
67 END IF
68*
69* Quick return if possible.
70*
71 IF( n.LE.0 )
72 $ RETURN
73*
74* Form x := alpha
75*
76 IF( incx.EQ.1 )
77 $ GO TO 20
78*
79* code for increments not equal to 1
80*
81* Set up the start point in X.
82*
83 IF( incx.GT.0 ) THEN
84 ix = 1
85 ELSE
86 ix = 1 - ( n - 1 ) * incx
87 END IF
88*
89 DO 10 i = 1, n
90 x( ix ) = alpha
91 ix = ix + incx
92 10 CONTINUE
93*
94 RETURN
95*
96* code for increment equal to 1
97*
98* clean-up loop
99*
100 20 m = mod( n, 4 )
101*
102 IF( m.EQ.0 )
103 $ GO TO 40
104*
105 DO 30 i = 1, m
106 x( i ) = alpha
107 30 CONTINUE
108 IF( n.LT.4 )
109 $ RETURN
110*
111 40 mp1 = m + 1
112 DO 50 i = mp1, n, 4
113 x( i ) = alpha
114 x( i + 1 ) = alpha
115 x( i + 2 ) = alpha
116 x( i + 3 ) = alpha
117 50 CONTINUE
118*
119 RETURN
120*
121* End of SSET
122*
123 END
sset
subroutine sset(n, alpha, x, incx)
Definition sset.f:2