Annotation of rpl/lapack/lapack/ztrttp.f, revision 1.1
1.1 ! bertrand 1: SUBROUTINE ZTRTTP( UPLO, N, A, LDA, AP, INFO )
! 2: *
! 3: * -- LAPACK routine (version 3.2) --
! 4: *
! 5: * -- Contributed by Fred Gustavson of the IBM Watson Research Center --
! 6: * -- and Julien Langou of the Univ. of Colorado Denver --
! 7: * -- November 2008 --
! 8: *
! 9: * -- LAPACK is a software package provided by Univ. of Tennessee, --
! 10: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
! 11: *
! 12: * .. Scalar Arguments ..
! 13: CHARACTER UPLO
! 14: INTEGER INFO, N, LDA
! 15: * ..
! 16: * .. Array Arguments ..
! 17: COMPLEX*16 A( LDA, * ), AP( * )
! 18: * ..
! 19: *
! 20: * Purpose
! 21: * =======
! 22: *
! 23: * ZTRTTP copies a triangular matrix A from full format (TR) to standard
! 24: * packed format (TP).
! 25: *
! 26: * Arguments
! 27: * =========
! 28: *
! 29: * UPLO (input) CHARACTER
! 30: * = 'U': A is upper triangular;
! 31: * = 'L': A is lower triangular.
! 32: *
! 33: * N (input) INTEGER
! 34: * The order of the matrices AP and A. N >= 0.
! 35: *
! 36: * A (input) COMPLEX*16 array, dimension (LDA,N)
! 37: * On entry, the triangular matrix A. If UPLO = 'U', the leading
! 38: * N-by-N upper triangular part of A contains the upper
! 39: * triangular part of the matrix A, and the strictly lower
! 40: * triangular part of A is not referenced. If UPLO = 'L', the
! 41: * leading N-by-N lower triangular part of A contains the lower
! 42: * triangular part of the matrix A, and the strictly upper
! 43: * triangular part of A is not referenced.
! 44: *
! 45: * LDA (input) INTEGER
! 46: * The leading dimension of the array A. LDA >= max(1,N).
! 47: *
! 48: * AP (output) COMPLEX*16 array, dimension ( N*(N+1)/2 ),
! 49: * On exit, the upper or lower triangular matrix A, packed
! 50: * columnwise in a linear array. The j-th column of A is stored
! 51: * in the array AP as follows:
! 52: * if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
! 53: * if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
! 54: *
! 55: * INFO (output) INTEGER
! 56: * = 0: successful exit
! 57: * < 0: if INFO = -i, the i-th argument had an illegal value
! 58: *
! 59: * =====================================================================
! 60: *
! 61: * .. Parameters ..
! 62: * ..
! 63: * .. Local Scalars ..
! 64: LOGICAL LOWER
! 65: INTEGER I, J, K
! 66: * ..
! 67: * .. External Functions ..
! 68: LOGICAL LSAME
! 69: EXTERNAL LSAME
! 70: * ..
! 71: * .. External Subroutines ..
! 72: EXTERNAL XERBLA
! 73: * ..
! 74: * .. Executable Statements ..
! 75: *
! 76: * Test the input parameters.
! 77: *
! 78: INFO = 0
! 79: LOWER = LSAME( UPLO, 'L' )
! 80: IF( .NOT.LOWER .AND. .NOT.LSAME( UPLO, 'U' ) ) THEN
! 81: INFO = -1
! 82: ELSE IF( N.LT.0 ) THEN
! 83: INFO = -2
! 84: ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
! 85: INFO = -4
! 86: END IF
! 87: IF( INFO.NE.0 ) THEN
! 88: CALL XERBLA( 'ZTRTTP', -INFO )
! 89: RETURN
! 90: END IF
! 91: *
! 92: IF( LOWER ) THEN
! 93: K = 0
! 94: DO J = 1, N
! 95: DO I = J, N
! 96: K = K + 1
! 97: AP( K ) = A( I, J )
! 98: END DO
! 99: END DO
! 100: ELSE
! 101: K = 0
! 102: DO J = 1, N
! 103: DO I = 1, J
! 104: K = K + 1
! 105: AP( K ) = A( I, J )
! 106: END DO
! 107: END DO
! 108: END IF
! 109: *
! 110: *
! 111: RETURN
! 112: *
! 113: * End of ZTRTTP
! 114: *
! 115: END
CVSweb interface <joel.bertrand@systella.fr>