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SUBROUTINE CTPTTR( UPLO, N, AP, A, LDA, INFO )
*
* -- LAPACK routine (version 3.2) --
*
* -- Contributed by Julien Langou of the Univ. of Colorado Denver --
* -- November 2008 --
*
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
* .. Scalar Arguments ..
CHARACTER UPLO
INTEGER INFO, N, LDA
* ..
* .. Array Arguments ..
COMPLEX A( LDA, * ), AP( * )
* ..
*
* Purpose
* =======
*
* CTPTTR copies a triangular matrix A from standard packed format (TP)
* to standard full format (TR).
*
* Arguments
* =========
*
* UPLO (input) CHARACTER*1
* = 'U': A is upper triangular.
* = 'L': A is lower triangular.
*
* N (input) INTEGER
* The order of the matrix A. N >= 0.
*
* AP (input) COMPLEX array, dimension ( N*(N+1)/2 ),
* On entry, the upper or lower triangular matrix A, packed
* columnwise in a linear array. The j-th column of A is stored
* in the array AP as follows:
* if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
* if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
*
* A (output) COMPLEX array, dimension ( LDA, N )
* On exit, the triangular matrix A. If UPLO = 'U', the leading
* N-by-N upper triangular part of A contains the upper
* triangular part of the matrix A, and the strictly lower
* triangular part of A is not referenced. If UPLO = 'L', the
* leading N-by-N lower triangular part of A contains the lower
* triangular part of the matrix A, and the strictly upper
* triangular part of A is not referenced.
*
* LDA (input) INTEGER
* The leading dimension of the array A. LDA >= max(1,N).
*
* INFO (output) INTEGER
* = 0: successful exit
* < 0: if INFO = -i, the i-th argument had an illegal value
*
* =====================================================================
*
* .. Parameters ..
* ..
* .. Local Scalars ..
LOGICAL LOWER
INTEGER I, J, K
* ..
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. External Subroutines ..
EXTERNAL XERBLA
* ..
* .. Executable Statements ..
*
* Test the input parameters.
*
INFO = 0
LOWER = LSAME( UPLO, 'L' )
IF( .NOT.LOWER .AND. .NOT.LSAME( UPLO, 'U' ) ) THEN
INFO = -1
ELSE IF( N.LT.0 ) THEN
INFO = -2
ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
INFO = -5
END IF
IF( INFO.NE.0 ) THEN
CALL XERBLA( 'CTPTTR', -INFO )
RETURN
END IF
*
IF( LOWER ) THEN
K = 0
DO J = 1, N
DO I = J, N
K = K + 1
A( I, J ) = AP( K )
END DO
END DO
ELSE
K = 0
DO J = 1, N
DO I = 1, J
K = K + 1
A( I, J ) = AP( K )
END DO
END DO
END IF
*
*
RETURN
*
* End of CTPTTR
*
END
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