```      DOUBLE PRECISION FUNCTION ZLANSP( NORM, UPLO, N, AP, WORK )
*
*  -- LAPACK auxiliary routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
CHARACTER          NORM, UPLO
INTEGER            N
*     ..
*     .. Array Arguments ..
DOUBLE PRECISION   WORK( * )
COMPLEX*16         AP( * )
*     ..
*
*  Purpose
*  =======
*
*  ZLANSP  returns the value of the one norm,  or the Frobenius norm, or
*  the  infinity norm,  or the  element of  largest absolute value  of a
*  complex symmetric matrix A,  supplied in packed form.
*
*  Description
*  ===========
*
*  ZLANSP returns the value
*
*     ZLANSP = ( max(abs(A(i,j))), NORM = 'M' or 'm'
*              (
*              ( norm1(A),         NORM = '1', 'O' or 'o'
*              (
*              ( normI(A),         NORM = 'I' or 'i'
*              (
*              ( normF(A),         NORM = 'F', 'f', 'E' or 'e'
*
*  where  norm1  denotes the  one norm of a matrix (maximum column sum),
*  normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
*  normF  denotes the  Frobenius norm of a matrix (square root of sum of
*  squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.
*
*  Arguments
*  =========
*
*  NORM    (input) CHARACTER*1
*          Specifies the value to be returned in ZLANSP as described
*          above.
*
*  UPLO    (input) CHARACTER*1
*          Specifies whether the upper or lower triangular part of the
*          symmetric matrix A is supplied.
*          = 'U':  Upper triangular part of A is supplied
*          = 'L':  Lower triangular part of A is supplied
*
*  N       (input) INTEGER
*          The order of the matrix A.  N >= 0.  When N = 0, ZLANSP is
*          set to zero.
*
*  AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2)
*          The upper or lower triangle of the symmetric 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.
*
*  WORK    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
*          where LWORK >= N when NORM = 'I' or '1' or 'O'; otherwise,
*          WORK is not referenced.
*
* =====================================================================
*
*     .. Parameters ..
DOUBLE PRECISION   ONE, ZERO
PARAMETER          ( ONE = 1.0D+0, ZERO = 0.0D+0 )
*     ..
*     .. Local Scalars ..
INTEGER            I, J, K
DOUBLE PRECISION   ABSA, SCALE, SUM, VALUE
*     ..
*     .. External Functions ..
LOGICAL            LSAME
EXTERNAL           LSAME
*     ..
*     .. External Subroutines ..
EXTERNAL           ZLASSQ
*     ..
*     .. Intrinsic Functions ..
INTRINSIC          ABS, DBLE, DIMAG, MAX, SQRT
*     ..
*     .. Executable Statements ..
*
IF( N.EQ.0 ) THEN
VALUE = ZERO
ELSE IF( LSAME( NORM, 'M' ) ) THEN
*
*        Find max(abs(A(i,j))).
*
VALUE = ZERO
IF( LSAME( UPLO, 'U' ) ) THEN
K = 1
DO 20 J = 1, N
DO 10 I = K, K + J - 1
VALUE = MAX( VALUE, ABS( AP( I ) ) )
10          CONTINUE
K = K + J
20       CONTINUE
ELSE
K = 1
DO 40 J = 1, N
DO 30 I = K, K + N - J
VALUE = MAX( VALUE, ABS( AP( I ) ) )
30          CONTINUE
K = K + N - J + 1
40       CONTINUE
END IF
ELSE IF( ( LSAME( NORM, 'I' ) ) .OR. ( LSAME( NORM, 'O' ) ) .OR.
\$         ( NORM.EQ.'1' ) ) THEN
*
*        Find normI(A) ( = norm1(A), since A is symmetric).
*
VALUE = ZERO
K = 1
IF( LSAME( UPLO, 'U' ) ) THEN
DO 60 J = 1, N
SUM = ZERO
DO 50 I = 1, J - 1
ABSA = ABS( AP( K ) )
SUM = SUM + ABSA
WORK( I ) = WORK( I ) + ABSA
K = K + 1
50          CONTINUE
WORK( J ) = SUM + ABS( AP( K ) )
K = K + 1
60       CONTINUE
DO 70 I = 1, N
VALUE = MAX( VALUE, WORK( I ) )
70       CONTINUE
ELSE
DO 80 I = 1, N
WORK( I ) = ZERO
80       CONTINUE
DO 100 J = 1, N
SUM = WORK( J ) + ABS( AP( K ) )
K = K + 1
DO 90 I = J + 1, N
ABSA = ABS( AP( K ) )
SUM = SUM + ABSA
WORK( I ) = WORK( I ) + ABSA
K = K + 1
90          CONTINUE
VALUE = MAX( VALUE, SUM )
100       CONTINUE
END IF
ELSE IF( ( LSAME( NORM, 'F' ) ) .OR. ( LSAME( NORM, 'E' ) ) ) THEN
*
*        Find normF(A).
*
SCALE = ZERO
SUM = ONE
K = 2
IF( LSAME( UPLO, 'U' ) ) THEN
DO 110 J = 2, N
CALL ZLASSQ( J-1, AP( K ), 1, SCALE, SUM )
K = K + J
110       CONTINUE
ELSE
DO 120 J = 1, N - 1
CALL ZLASSQ( N-J, AP( K ), 1, SCALE, SUM )
K = K + N - J + 1
120       CONTINUE
END IF
SUM = 2*SUM
K = 1
DO 130 I = 1, N
IF( DBLE( AP( K ) ).NE.ZERO ) THEN
ABSA = ABS( DBLE( AP( K ) ) )
IF( SCALE.LT.ABSA ) THEN
SUM = ONE + SUM*( SCALE / ABSA )**2
SCALE = ABSA
ELSE
SUM = SUM + ( ABSA / SCALE )**2
END IF
END IF
IF( DIMAG( AP( K ) ).NE.ZERO ) THEN
ABSA = ABS( DIMAG( AP( K ) ) )
IF( SCALE.LT.ABSA ) THEN
SUM = ONE + SUM*( SCALE / ABSA )**2
SCALE = ABSA
ELSE
SUM = SUM + ( ABSA / SCALE )**2
END IF
END IF
IF( LSAME( UPLO, 'U' ) ) THEN
K = K + I + 1
ELSE
K = K + N - I + 1
END IF
130    CONTINUE
VALUE = SCALE*SQRT( SUM )
END IF
*
ZLANSP = VALUE
RETURN
*
*     End of ZLANSP
*
END

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