Annotation of rpl/lapack/lapack/zlat2c.f, revision 1.5
1.1 bertrand 1: SUBROUTINE ZLAT2C( UPLO, N, A, LDA, SA, LDSA, INFO )
2: *
1.5 ! bertrand 3: * -- LAPACK PROTOTYPE auxiliary routine (version 3.3.1) --
1.1 bertrand 4: * -- LAPACK is a software package provided by Univ. of Tennessee, --
5: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.5 ! bertrand 6: * -- April 2011 --
1.1 bertrand 7: *
8: * .. Scalar Arguments ..
9: CHARACTER UPLO
10: INTEGER INFO, LDA, LDSA, N
11: * ..
12: * .. Array Arguments ..
13: COMPLEX SA( LDSA, * )
14: COMPLEX*16 A( LDA, * )
15: * ..
16: *
17: * Purpose
18: * =======
19: *
20: * ZLAT2C converts a COMPLEX*16 triangular matrix, SA, to a COMPLEX
21: * triangular matrix, A.
22: *
23: * RMAX is the overflow for the SINGLE PRECISION arithmetic
24: * ZLAT2C checks that all the entries of A are between -RMAX and
25: * RMAX. If not the convertion is aborted and a flag is raised.
26: *
27: * This is an auxiliary routine so there is no argument checking.
28: *
29: * Arguments
30: * =========
31: *
32: * UPLO (input) CHARACTER*1
33: * = 'U': A is upper triangular;
34: * = 'L': A is lower triangular.
35: *
36: * N (input) INTEGER
37: * The number of rows and columns of the matrix A. N >= 0.
38: *
39: * A (input) COMPLEX*16 array, dimension (LDA,N)
40: * On entry, the N-by-N triangular coefficient matrix A.
41: *
42: * LDA (input) INTEGER
43: * The leading dimension of the array A. LDA >= max(1,N).
44: *
45: * SA (output) COMPLEX array, dimension (LDSA,N)
46: * Only the UPLO part of SA is referenced. On exit, if INFO=0,
47: * the N-by-N coefficient matrix SA; if INFO>0, the content of
48: * the UPLO part of SA is unspecified.
49: *
50: * LDSA (input) INTEGER
51: * The leading dimension of the array SA. LDSA >= max(1,M).
52: *
53: * INFO (output) INTEGER
54: * = 0: successful exit.
55: * = 1: an entry of the matrix A is greater than the SINGLE
56: * PRECISION overflow threshold, in this case, the content
57: * of the UPLO part of SA in exit is unspecified.
58: *
1.5 ! bertrand 59: * =====================================================================
1.1 bertrand 60: *
61: * .. Local Scalars ..
62: INTEGER I, J
63: DOUBLE PRECISION RMAX
64: LOGICAL UPPER
65: * ..
66: * .. Intrinsic Functions ..
67: INTRINSIC DBLE, DIMAG
68: * ..
69: * .. External Functions ..
70: REAL SLAMCH
71: LOGICAL LSAME
72: EXTERNAL SLAMCH, LSAME
73: * ..
74: * .. Executable Statements ..
75: *
76: RMAX = SLAMCH( 'O' )
77: UPPER = LSAME( UPLO, 'U' )
78: IF( UPPER ) THEN
79: DO 20 J = 1, N
80: DO 10 I = 1, J
81: IF( ( DBLE( A( I, J ) ).LT.-RMAX ) .OR.
1.5 ! bertrand 82: $ ( DBLE( A( I, J ) ).GT.RMAX ) .OR.
! 83: $ ( DIMAG( A( I, J ) ).LT.-RMAX ) .OR.
! 84: $ ( DIMAG( A( I, J ) ).GT.RMAX ) ) THEN
1.1 bertrand 85: INFO = 1
86: GO TO 50
87: END IF
88: SA( I, J ) = A( I, J )
89: 10 CONTINUE
90: 20 CONTINUE
91: ELSE
92: DO 40 J = 1, N
93: DO 30 I = J, N
94: IF( ( DBLE( A( I, J ) ).LT.-RMAX ) .OR.
1.5 ! bertrand 95: $ ( DBLE( A( I, J ) ).GT.RMAX ) .OR.
! 96: $ ( DIMAG( A( I, J ) ).LT.-RMAX ) .OR.
! 97: $ ( DIMAG( A( I, J ) ).GT.RMAX ) ) THEN
1.1 bertrand 98: INFO = 1
99: GO TO 50
100: END IF
101: SA( I, J ) = A( I, J )
102: 30 CONTINUE
103: 40 CONTINUE
104: END IF
105: 50 CONTINUE
106: *
107: RETURN
108: *
109: * End of ZLAT2C
110: *
111: END
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