1 SUBROUTINE DLAUU2( UPLO, N, A, LDA, INFO )
2 *
3 * -- LAPACK auxiliary routine (version 3.3.1) --
4 * -- LAPACK is a software package provided by Univ. of Tennessee, --
5 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
6 * -- April 2011 --
7 *
8 * .. Scalar Arguments ..
9 CHARACTER UPLO
10 INTEGER INFO, LDA, N
11 * ..
12 * .. Array Arguments ..
13 DOUBLE PRECISION A( LDA, * )
14 * ..
15 *
16 * Purpose
17 * =======
18 *
19 * DLAUU2 computes the product U * U**T or L**T * L, where the triangular
20 * factor U or L is stored in the upper or lower triangular part of
21 * the array A.
22 *
23 * If UPLO = 'U' or 'u' then the upper triangle of the result is stored,
24 * overwriting the factor U in A.
25 * If UPLO = 'L' or 'l' then the lower triangle of the result is stored,
26 * overwriting the factor L in A.
27 *
28 * This is the unblocked form of the algorithm, calling Level 2 BLAS.
29 *
30 * Arguments
31 * =========
32 *
33 * UPLO (input) CHARACTER*1
34 * Specifies whether the triangular factor stored in the array A
35 * is upper or lower triangular:
36 * = 'U': Upper triangular
37 * = 'L': Lower triangular
38 *
39 * N (input) INTEGER
40 * The order of the triangular factor U or L. N >= 0.
41 *
42 * A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
43 * On entry, the triangular factor U or L.
44 * On exit, if UPLO = 'U', the upper triangle of A is
45 * overwritten with the upper triangle of the product U * U**T;
46 * if UPLO = 'L', the lower triangle of A is overwritten with
47 * the lower triangle of the product L**T * L.
48 *
49 * LDA (input) INTEGER
50 * The leading dimension of the array A. LDA >= max(1,N).
51 *
52 * INFO (output) INTEGER
53 * = 0: successful exit
54 * < 0: if INFO = -k, the k-th argument had an illegal value
55 *
56 * =====================================================================
57 *
58 * .. Parameters ..
59 DOUBLE PRECISION ONE
60 PARAMETER ( ONE = 1.0D+0 )
61 * ..
62 * .. Local Scalars ..
63 LOGICAL UPPER
64 INTEGER I
65 DOUBLE PRECISION AII
66 * ..
67 * .. External Functions ..
68 LOGICAL LSAME
69 DOUBLE PRECISION DDOT
70 EXTERNAL LSAME, DDOT
71 * ..
72 * .. External Subroutines ..
73 EXTERNAL DGEMV, DSCAL, XERBLA
74 * ..
75 * .. Intrinsic Functions ..
76 INTRINSIC MAX
77 * ..
78 * .. Executable Statements ..
79 *
80 * Test the input parameters.
81 *
82 INFO = 0
83 UPPER = LSAME( UPLO, 'U' )
84 IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
85 INFO = -1
86 ELSE IF( N.LT.0 ) THEN
87 INFO = -2
88 ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
89 INFO = -4
90 END IF
91 IF( INFO.NE.0 ) THEN
92 CALL XERBLA( 'DLAUU2', -INFO )
93 RETURN
94 END IF
95 *
96 * Quick return if possible
97 *
98 IF( N.EQ.0 )
99 $ RETURN
100 *
101 IF( UPPER ) THEN
102 *
103 * Compute the product U * U**T.
104 *
105 DO 10 I = 1, N
106 AII = A( I, I )
107 IF( I.LT.N ) THEN
108 A( I, I ) = DDOT( N-I+1, A( I, I ), LDA, A( I, I ), LDA )
109 CALL DGEMV( 'No transpose', I-1, N-I, ONE, A( 1, I+1 ),
110 $ LDA, A( I, I+1 ), LDA, AII, A( 1, I ), 1 )
111 ELSE
112 CALL DSCAL( I, AII, A( 1, I ), 1 )
113 END IF
114 10 CONTINUE
115 *
116 ELSE
117 *
118 * Compute the product L**T * L.
119 *
120 DO 20 I = 1, N
121 AII = A( I, I )
122 IF( I.LT.N ) THEN
123 A( I, I ) = DDOT( N-I+1, A( I, I ), 1, A( I, I ), 1 )
124 CALL DGEMV( 'Transpose', N-I, I-1, ONE, A( I+1, 1 ), LDA,
125 $ A( I+1, I ), 1, AII, A( I, 1 ), LDA )
126 ELSE
127 CALL DSCAL( I, AII, A( I, 1 ), LDA )
128 END IF
129 20 CONTINUE
130 END IF
131 *
132 RETURN
133 *
134 * End of DLAUU2
135 *
136 END
2 *
3 * -- LAPACK auxiliary routine (version 3.3.1) --
4 * -- LAPACK is a software package provided by Univ. of Tennessee, --
5 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
6 * -- April 2011 --
7 *
8 * .. Scalar Arguments ..
9 CHARACTER UPLO
10 INTEGER INFO, LDA, N
11 * ..
12 * .. Array Arguments ..
13 DOUBLE PRECISION A( LDA, * )
14 * ..
15 *
16 * Purpose
17 * =======
18 *
19 * DLAUU2 computes the product U * U**T or L**T * L, where the triangular
20 * factor U or L is stored in the upper or lower triangular part of
21 * the array A.
22 *
23 * If UPLO = 'U' or 'u' then the upper triangle of the result is stored,
24 * overwriting the factor U in A.
25 * If UPLO = 'L' or 'l' then the lower triangle of the result is stored,
26 * overwriting the factor L in A.
27 *
28 * This is the unblocked form of the algorithm, calling Level 2 BLAS.
29 *
30 * Arguments
31 * =========
32 *
33 * UPLO (input) CHARACTER*1
34 * Specifies whether the triangular factor stored in the array A
35 * is upper or lower triangular:
36 * = 'U': Upper triangular
37 * = 'L': Lower triangular
38 *
39 * N (input) INTEGER
40 * The order of the triangular factor U or L. N >= 0.
41 *
42 * A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
43 * On entry, the triangular factor U or L.
44 * On exit, if UPLO = 'U', the upper triangle of A is
45 * overwritten with the upper triangle of the product U * U**T;
46 * if UPLO = 'L', the lower triangle of A is overwritten with
47 * the lower triangle of the product L**T * L.
48 *
49 * LDA (input) INTEGER
50 * The leading dimension of the array A. LDA >= max(1,N).
51 *
52 * INFO (output) INTEGER
53 * = 0: successful exit
54 * < 0: if INFO = -k, the k-th argument had an illegal value
55 *
56 * =====================================================================
57 *
58 * .. Parameters ..
59 DOUBLE PRECISION ONE
60 PARAMETER ( ONE = 1.0D+0 )
61 * ..
62 * .. Local Scalars ..
63 LOGICAL UPPER
64 INTEGER I
65 DOUBLE PRECISION AII
66 * ..
67 * .. External Functions ..
68 LOGICAL LSAME
69 DOUBLE PRECISION DDOT
70 EXTERNAL LSAME, DDOT
71 * ..
72 * .. External Subroutines ..
73 EXTERNAL DGEMV, DSCAL, XERBLA
74 * ..
75 * .. Intrinsic Functions ..
76 INTRINSIC MAX
77 * ..
78 * .. Executable Statements ..
79 *
80 * Test the input parameters.
81 *
82 INFO = 0
83 UPPER = LSAME( UPLO, 'U' )
84 IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
85 INFO = -1
86 ELSE IF( N.LT.0 ) THEN
87 INFO = -2
88 ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
89 INFO = -4
90 END IF
91 IF( INFO.NE.0 ) THEN
92 CALL XERBLA( 'DLAUU2', -INFO )
93 RETURN
94 END IF
95 *
96 * Quick return if possible
97 *
98 IF( N.EQ.0 )
99 $ RETURN
100 *
101 IF( UPPER ) THEN
102 *
103 * Compute the product U * U**T.
104 *
105 DO 10 I = 1, N
106 AII = A( I, I )
107 IF( I.LT.N ) THEN
108 A( I, I ) = DDOT( N-I+1, A( I, I ), LDA, A( I, I ), LDA )
109 CALL DGEMV( 'No transpose', I-1, N-I, ONE, A( 1, I+1 ),
110 $ LDA, A( I, I+1 ), LDA, AII, A( 1, I ), 1 )
111 ELSE
112 CALL DSCAL( I, AII, A( 1, I ), 1 )
113 END IF
114 10 CONTINUE
115 *
116 ELSE
117 *
118 * Compute the product L**T * L.
119 *
120 DO 20 I = 1, N
121 AII = A( I, I )
122 IF( I.LT.N ) THEN
123 A( I, I ) = DDOT( N-I+1, A( I, I ), 1, A( I, I ), 1 )
124 CALL DGEMV( 'Transpose', N-I, I-1, ONE, A( I+1, 1 ), LDA,
125 $ A( I+1, I ), 1, AII, A( I, 1 ), LDA )
126 ELSE
127 CALL DSCAL( I, AII, A( I, 1 ), LDA )
128 END IF
129 20 CONTINUE
130 END IF
131 *
132 RETURN
133 *
134 * End of DLAUU2
135 *
136 END