 LAPACK  3.4.2 LAPACK: Linear Algebra PACKage
zlacon.f File Reference

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## Functions/Subroutines

subroutine zlacon (N, V, X, EST, KASE)
ZLACON estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products.

## Function/Subroutine Documentation

 subroutine zlacon ( integer N, complex*16, dimension( n ) V, complex*16, dimension( n ) X, double precision EST, integer KASE )

ZLACON estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products.

Purpose:
``` ZLACON estimates the 1-norm of a square, complex matrix A.
Reverse communication is used for evaluating matrix-vector products.```
Parameters:
 [in] N ``` N is INTEGER The order of the matrix. N >= 1.``` [out] V ``` V is COMPLEX*16 array, dimension (N) On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned).``` [in,out] X ``` X is COMPLEX*16 array, dimension (N) On an intermediate return, X should be overwritten by A * X, if KASE=1, A**H * X, if KASE=2, where A**H is the conjugate transpose of A, and ZLACON must be re-called with all the other parameters unchanged.``` [in,out] EST ``` EST is DOUBLE PRECISION On entry with KASE = 1 or 2 and JUMP = 3, EST should be unchanged from the previous call to ZLACON. On exit, EST is an estimate (a lower bound) for norm(A). ``` [in,out] KASE ``` KASE is INTEGER On the initial call to ZLACON, KASE should be 0. On an intermediate return, KASE will be 1 or 2, indicating whether X should be overwritten by A * X or A**H * X. On the final return from ZLACON, KASE will again be 0.```
Date:
September 2012
Further Details:
Originally named CONEST, dated March 16, 1988.