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1.1 bertrand 1: SUBROUTINE ZSYSWAPR( UPLO, N, A, I1, I2)
2: *
3: * -- LAPACK auxiliary routine (version 3.3.0) --
4: * -- LAPACK is a software package provided by Univ. of Tennessee, --
5: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
6: * November 2010
7: *
8: * .. Scalar Arguments ..
9: CHARACTER UPLO
10: INTEGER I1, I2, N
11: * ..
12: * .. Array Arguments ..
13: DOUBLE COMPLEX A(N,N)
14: *
15: * Purpose
16: * =======
17: *
18: * ZSYSWAPR applies an elementary permutation on the rows and the columns of
19: * a symmetric matrix.
20: *
21: * Arguments
22: * =========
23: *
24: * UPLO (input) CHARACTER*1
25: * Specifies whether the details of the factorization are stored
26: * as an upper or lower triangular matrix.
27: * = 'U': Upper triangular, form is A = U*D*U**T;
28: * = 'L': Lower triangular, form is A = L*D*L**T.
29: *
30: * N (input) INTEGER
31: * The order of the matrix A. N >= 0.
32: *
33: * A (input/output) DOUBLE COMPLEX array, dimension (LDA,N)
34: * On entry, the NB diagonal matrix D and the multipliers
35: * used to obtain the factor U or L as computed by ZSYTRF.
36: *
37: * On exit, if INFO = 0, the (symmetric) inverse of the original
38: * matrix. If UPLO = 'U', the upper triangular part of the
39: * inverse is formed and the part of A below the diagonal is not
40: * referenced; if UPLO = 'L' the lower triangular part of the
41: * inverse is formed and the part of A above the diagonal is
42: * not referenced.
43: *
44: * I1 (input) INTEGER
45: * Index of the first row to swap
46: *
47: * I2 (input) INTEGER
48: * Index of the second row to swap
49: *
50: * =====================================================================
51: *
52: * ..
53: * .. Local Scalars ..
54: LOGICAL UPPER
55: INTEGER I
56: DOUBLE COMPLEX TMP
57: *
58: * .. External Functions ..
59: LOGICAL LSAME
60: EXTERNAL LSAME
61: * ..
62: * .. External Subroutines ..
63: EXTERNAL ZSWAP
64: * ..
65: * .. Executable Statements ..
66: *
67: UPPER = LSAME( UPLO, 'U' )
68: IF (UPPER) THEN
69: *
70: * UPPER
71: * first swap
72: * - swap column I1 and I2 from I1 to I1-1
73: CALL ZSWAP( I1-1, A(1,I1), 1, A(1,I2), 1 )
74: *
75: * second swap :
76: * - swap A(I1,I1) and A(I2,I2)
77: * - swap row I1 from I1+1 to I2-1 with col I2 from I1+1 to I2-1
78: TMP=A(I1,I1)
79: A(I1,I1)=A(I2,I2)
80: A(I2,I2)=TMP
81: *
82: DO I=1,I2-I1-1
83: TMP=A(I1,I1+I)
84: A(I1,I1+I)=A(I1+I,I2)
85: A(I1+I,I2)=TMP
86: END DO
87: *
88: * third swap
89: * - swap row I1 and I2 from I2+1 to N
90: DO I=I2+1,N
91: TMP=A(I1,I)
92: A(I1,I)=A(I2,I)
93: A(I2,I)=TMP
94: END DO
95: *
96: ELSE
97: *
98: * LOWER
99: * first swap
100: * - swap row I1 and I2 from I1 to I1-1
101: CALL ZSWAP( I1-1, A(I1,1), N, A(I2,1), N )
102: *
103: * second swap :
104: * - swap A(I1,I1) and A(I2,I2)
105: * - swap col I1 from I1+1 to I2-1 with row I2 from I1+1 to I2-1
106: TMP=A(I1,I1)
107: A(I1,I1)=A(I2,I2)
108: A(I2,I2)=TMP
109: *
110: DO I=1,I2-I1-1
111: TMP=A(I1+I,I1)
112: A(I1+I,I1)=A(I2,I1+I)
113: A(I2,I1+I)=TMP
114: END DO
115: *
116: * third swap
117: * - swap col I1 and I2 from I2+1 to N
118: DO I=I2+1,N
119: TMP=A(I,I1)
120: A(I,I1)=A(I,I2)
121: A(I,I2)=TMP
122: END DO
123: *
124: ENDIF
125: END SUBROUTINE ZSYSWAPR
126: