--- rpl/lapack/lapack/zlangt.f	2010/08/06 15:32:44	1.4
+++ rpl/lapack/lapack/zlangt.f	2023/08/07 08:39:29	1.18
@@ -1,9 +1,112 @@
+*> \brief \b ZLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general tridiagonal matrix.
+*
+*  =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+*            http://www.netlib.org/lapack/explore-html/
+*
+*> \htmlonly
+*> Download ZLANGT + dependencies
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlangt.f">
+*> [TGZ]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlangt.f">
+*> [ZIP]</a>
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlangt.f">
+*> [TXT]</a>
+*> \endhtmlonly
+*
+*  Definition:
+*  ===========
+*
+*       DOUBLE PRECISION FUNCTION ZLANGT( NORM, N, DL, D, DU )
+*
+*       .. Scalar Arguments ..
+*       CHARACTER          NORM
+*       INTEGER            N
+*       ..
+*       .. Array Arguments ..
+*       COMPLEX*16         D( * ), DL( * ), DU( * )
+*       ..
+*
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*> ZLANGT  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 tridiagonal matrix A.
+*> \endverbatim
+*>
+*> \return ZLANGT
+*> \verbatim
+*>
+*>    ZLANGT = ( 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.
+*> \endverbatim
+*
+*  Arguments:
+*  ==========
+*
+*> \param[in] NORM
+*> \verbatim
+*>          NORM is CHARACTER*1
+*>          Specifies the value to be returned in ZLANGT as described
+*>          above.
+*> \endverbatim
+*>
+*> \param[in] N
+*> \verbatim
+*>          N is INTEGER
+*>          The order of the matrix A.  N >= 0.  When N = 0, ZLANGT is
+*>          set to zero.
+*> \endverbatim
+*>
+*> \param[in] DL
+*> \verbatim
+*>          DL is COMPLEX*16 array, dimension (N-1)
+*>          The (n-1) sub-diagonal elements of A.
+*> \endverbatim
+*>
+*> \param[in] D
+*> \verbatim
+*>          D is COMPLEX*16 array, dimension (N)
+*>          The diagonal elements of A.
+*> \endverbatim
+*>
+*> \param[in] DU
+*> \verbatim
+*>          DU is COMPLEX*16 array, dimension (N-1)
+*>          The (n-1) super-diagonal elements of A.
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \ingroup complex16OTHERauxiliary
+*
+*  =====================================================================
       DOUBLE PRECISION FUNCTION ZLANGT( NORM, N, DL, D, DU )
 *
-*  -- LAPACK auxiliary routine (version 3.2) --
+*  -- LAPACK auxiliary routine --
 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-*     November 2006
 *
 *     .. Scalar Arguments ..
       CHARACTER          NORM
@@ -13,51 +116,6 @@
       COMPLEX*16         D( * ), DL( * ), DU( * )
 *     ..
 *
-*  Purpose
-*  =======
-*
-*  ZLANGT  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 tridiagonal matrix A.
-*
-*  Description
-*  ===========
-*
-*  ZLANGT returns the value
-*
-*     ZLANGT = ( 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 ZLANGT as described
-*          above.
-*
-*  N       (input) INTEGER
-*          The order of the matrix A.  N >= 0.  When N = 0, ZLANGT is
-*          set to zero.
-*
-*  DL      (input) COMPLEX*16 array, dimension (N-1)
-*          The (n-1) sub-diagonal elements of A.
-*
-*  D       (input) COMPLEX*16 array, dimension (N)
-*          The diagonal elements of A.
-*
-*  DU      (input) COMPLEX*16 array, dimension (N-1)
-*          The (n-1) super-diagonal elements of A.
-*
 *  =====================================================================
 *
 *     .. Parameters ..
@@ -66,17 +124,17 @@
 *     ..
 *     .. Local Scalars ..
       INTEGER            I
-      DOUBLE PRECISION   ANORM, SCALE, SUM
+      DOUBLE PRECISION   ANORM, SCALE, SUM, TEMP
 *     ..
 *     .. External Functions ..
-      LOGICAL            LSAME
-      EXTERNAL           LSAME
+      LOGICAL            LSAME, DISNAN
+      EXTERNAL           LSAME, DISNAN
 *     ..
 *     .. External Subroutines ..
       EXTERNAL           ZLASSQ
 *     ..
 *     .. Intrinsic Functions ..
-      INTRINSIC          ABS, MAX, SQRT
+      INTRINSIC          ABS, SQRT
 *     ..
 *     .. Executable Statements ..
 *
@@ -88,9 +146,12 @@
 *
          ANORM = ABS( D( N ) )
          DO 10 I = 1, N - 1
-            ANORM = MAX( ANORM, ABS( DL( I ) ) )
-            ANORM = MAX( ANORM, ABS( D( I ) ) )
-            ANORM = MAX( ANORM, ABS( DU( I ) ) )
+            IF( ANORM.LT.ABS( DL( I ) ) .OR. DISNAN( ABS( DL( I ) ) ) )
+     $           ANORM = ABS(DL(I))
+            IF( ANORM.LT.ABS( D( I ) ) .OR. DISNAN( ABS( D( I ) ) ) )
+     $           ANORM = ABS(D(I))
+            IF( ANORM.LT.ABS( DU( I ) ) .OR. DISNAN (ABS( DU( I ) ) ) )
+     $           ANORM = ABS(DU(I))
    10    CONTINUE
       ELSE IF( LSAME( NORM, 'O' ) .OR. NORM.EQ.'1' ) THEN
 *
@@ -99,11 +160,12 @@
          IF( N.EQ.1 ) THEN
             ANORM = ABS( D( 1 ) )
          ELSE
-            ANORM = MAX( ABS( D( 1 ) )+ABS( DL( 1 ) ),
-     $              ABS( D( N ) )+ABS( DU( N-1 ) ) )
+            ANORM = ABS( D( 1 ) )+ABS( DL( 1 ) )
+            TEMP = ABS( D( N ) )+ABS( DU( N-1 ) )
+            IF( ANORM .LT. TEMP .OR. DISNAN( TEMP ) ) ANORM = TEMP
             DO 20 I = 2, N - 1
-               ANORM = MAX( ANORM, ABS( D( I ) )+ABS( DL( I ) )+
-     $                 ABS( DU( I-1 ) ) )
+               TEMP = ABS( D( I ) )+ABS( DL( I ) )+ABS( DU( I-1 ) )
+               IF( ANORM .LT. TEMP .OR. DISNAN( TEMP ) ) ANORM = TEMP
    20       CONTINUE
          END IF
       ELSE IF( LSAME( NORM, 'I' ) ) THEN
@@ -113,11 +175,12 @@
          IF( N.EQ.1 ) THEN
             ANORM = ABS( D( 1 ) )
          ELSE
-            ANORM = MAX( ABS( D( 1 ) )+ABS( DU( 1 ) ),
-     $              ABS( D( N ) )+ABS( DL( N-1 ) ) )
+            ANORM = ABS( D( 1 ) )+ABS( DU( 1 ) )
+            TEMP = ABS( D( N ) )+ABS( DL( N-1 ) )
+            IF( ANORM .LT. TEMP .OR. DISNAN( TEMP ) ) ANORM = TEMP
             DO 30 I = 2, N - 1
-               ANORM = MAX( ANORM, ABS( D( I ) )+ABS( DU( I ) )+
-     $                 ABS( DL( I-1 ) ) )
+               TEMP = ABS( D( I ) )+ABS( DU( I ) )+ABS( DL( I-1 ) )
+               IF( ANORM .LT. TEMP .OR. DISNAN( TEMP ) ) ANORM = TEMP
    30       CONTINUE
          END IF
       ELSE IF( ( LSAME( NORM, 'F' ) ) .OR. ( LSAME( NORM, 'E' ) ) ) THEN