1CLACON(1)           LAPACK auxiliary routine (version 3.2)           CLACON(1)
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NAME

6       CLACON - estimates the 1-norm of a square, complex matrix A
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SYNOPSIS

9       SUBROUTINE CLACON( N, V, X, EST, KASE )
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11           INTEGER        KASE, N
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13           REAL           EST
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15           COMPLEX        V( N ), X( N )
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PURPOSE

18       CLACON  estimates  the  1-norm  of a square, complex matrix A.  Reverse
19       communication is used for evaluating matrix-vector products.
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ARGUMENTS

22       N      (input) INTEGER
23              The order of the matrix.  N >= 1.
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25       V      (workspace) COMPLEX array, dimension (N)
26              On the final return, V = A*W,  where  EST =  norm(V)/norm(W)  (W
27              is not returned).
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29       X      (input/output) COMPLEX array, dimension (N)
30              On  an  intermediate  return,  X should be overwritten by A * X,
31              if KASE=1, A' * X,  if KASE=2, where A' is the conjugate  trans‐
32              pose  of  A,  and  CLACON  must  be re-called with all the other
33              parameters unchanged.
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35       EST    (input/output) REAL
36              On entry with KASE = 1  or  2  and  JUMP  =  3,  EST  should  be
37              unchanged  from the previous call to CLACON.  On exit, EST is an
38              estimate (a lower bound) for norm(A).
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40       KASE   (input/output) INTEGER
41              On the initial call to CLACON, KASE should be 0.  On an interme‐
42              diate  return,  KASE will be 1 or 2, indicating whether X should
43              be overwritten by A * X  or A' * X.  On the  final  return  from
44              CLACON, KASE will again be 0.
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FURTHER DETAILS

47       Contributed by Nick Higham, University of Manchester.
48       Originally named CONEST, dated March 16, 1988.
49       Reference: N.J. Higham, "FORTRAN codes for estimating the one-norm of a
50       real or complex matrix, with applications to condition estimation", ACM
51       Trans.  Math.  Soft., vol. 14, no. 4, pp. 381-396, December 1988.  Last
52       modified:  April, 1999
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56 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       CLACON(1)