text: /* dlanhs.f -- translated by f2c (version 20061008).
     You must link the resulting object file with libf2c:
  	on Microsoft Windows system, link with libf2c.lib;
  	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
  	or, if you install libf2c.a in a standard place, with -lf2c -lm
  	-- in that order, at the end of the command line, as in
  		cc *.o -lf2c -lm
  	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
  
  		http://www.netlib.org/f2c/libf2c.zip
  */
  
  #include "f2c.h"
  #include "blaswrap.h"
  
  /* Table of constant values */
  
  static integer c__1 = 1;
  
  doublereal dlanhs_(char *norm, integer *n, doublereal *a, integer *lda, 
  	doublereal *work)
  {
      /* System generated locals */
      integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
      doublereal ret_val, d__1, d__2, d__3;
  
      /* Builtin functions */
      double sqrt(doublereal);
  
      /* Local variables */
      integer i__, j;
      doublereal sum, scale;
      extern logical lsame_(char *, char *);
      doublereal value;
      extern /* Subroutine */ int dlassq_(integer *, doublereal *, integer *, 
  	    doublereal *, doublereal *);
  
  
  /*  -- LAPACK auxiliary routine (version 3.2) -- */
  /*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
  /*     November 2006 */
  
  /*     .. Scalar Arguments .. */
  /*     .. */
  /*     .. Array Arguments .. */
  /*     .. */
  
  /*  Purpose */
  /*  ======= */
  
  /*  DLANHS  returns the value of the one norm,  or the Frobenius norm, or */
  /*  the  infinity norm,  or the  element of  largest absolute value  of a */
  /*  Hessenberg matrix A. */
  
  /*  Description */
  /*  =========== */
  
  /*  DLANHS returns the value */
  
  /*     DLANHS = ( 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 DLANHS as described */
  /*          above. */
  
  /*  N       (input) INTEGER */
  /*          The order of the matrix A.  N >= 0.  When N = 0, DLANHS is */
  /*          set to zero. */
  
  /*  A       (input) DOUBLE PRECISION array, dimension (LDA,N) */
  /*          The n by n upper Hessenberg matrix A; the part of A below the */
  /*          first sub-diagonal is not referenced. */
  
  /*  LDA     (input) INTEGER */
  /*          The leading dimension of the array A.  LDA >= max(N,1). */
  
  /*  WORK    (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)), */
  /*          where LWORK >= N when NORM = 'I'; otherwise, WORK is not */
  /*          referenced. */
  
  /* ===================================================================== */
  
  /*     .. Parameters .. */
  /*     .. */
  /*     .. Local Scalars .. */
  /*     .. */
  /*     .. External Subroutines .. */
  /*     .. */
  /*     .. External Functions .. */
  /*     .. */
  /*     .. Intrinsic Functions .. */
  /*     .. */
  /*     .. Executable Statements .. */
  
      /* Parameter adjustments */
      a_dim1 = *lda;
      a_offset = 1 + a_dim1;
      a -= a_offset;
      --work;
  
      /* Function Body */
      if (*n == 0) {
  	value = 0.;
      } else if (lsame_(norm, "M")) {
  
  /*        Find max(abs(A(i,j))). */
  
  	value = 0.;
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  /* Computing MIN */
  	    i__3 = *n, i__4 = j + 1;
  	    i__2 = min(i__3,i__4);
  	    for (i__ = 1; i__ <= i__2; ++i__) {
  /* Computing MAX */
  		d__2 = value, d__3 = (d__1 = a[i__ + j * a_dim1], abs(d__1));
  		value = max(d__2,d__3);
  /* L10: */
  	    }
  /* L20: */
  	}
      } else if (lsame_(norm, "O") || *(unsigned char *)
  	    norm == '1') {
  
  /*        Find norm1(A). */
  
  	value = 0.;
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  	    sum = 0.;
  /* Computing MIN */
  	    i__3 = *n, i__4 = j + 1;
  	    i__2 = min(i__3,i__4);
  	    for (i__ = 1; i__ <= i__2; ++i__) {
  		sum += (d__1 = a[i__ + j * a_dim1], abs(d__1));
  /* L30: */
  	    }
  	    value = max(value,sum);
  /* L40: */
  	}
      } else if (lsame_(norm, "I")) {
  
  /*        Find normI(A). */
  
  	i__1 = *n;
  	for (i__ = 1; i__ <= i__1; ++i__) {
  	    work[i__] = 0.;
  /* L50: */
  	}
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  /* Computing MIN */
  	    i__3 = *n, i__4 = j + 1;
  	    i__2 = min(i__3,i__4);
  	    for (i__ = 1; i__ <= i__2; ++i__) {
  		work[i__] += (d__1 = a[i__ + j * a_dim1], abs(d__1));
  /* L60: */
  	    }
  /* L70: */
  	}
  	value = 0.;
  	i__1 = *n;
  	for (i__ = 1; i__ <= i__1; ++i__) {
  /* Computing MAX */
  	    d__1 = value, d__2 = work[i__];
  	    value = max(d__1,d__2);
  /* L80: */
  	}
      } else if (lsame_(norm, "F") || lsame_(norm, "E")) {
  
  /*        Find normF(A). */
  
  	scale = 0.;
  	sum = 1.;
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  /* Computing MIN */
  	    i__3 = *n, i__4 = j + 1;
  	    i__2 = min(i__3,i__4);
  	    dlassq_(&i__2, &a[j * a_dim1 + 1], &c__1, &scale, &sum);
  /* L90: */
  	}
  	value = scale * sqrt(sum);
      }
  
      ret_val = value;
      return ret_val;
  
  /*     End of DLANHS */
  
  } /* dlanhs_ */
  