Annotation of rpl/lapack/lapack/zsyswapr.f, revision 1.1
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:
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