From: bv <bvoh@sdynamix.com>
Subject: Re: Integration of system of 1st order diff. equations
Date: Wed, 20 Sep 2000 16:48:48 -0700
Newsgroups: sci.math.num-analysis
Summary: [missing]

Andreas Meyer wrote:
> 
> In the context of matrix exponentials, I came across the problem of
> calculating cosh(sqrt(MATRIX)*t). As far as I understand expokit, the
> evaluation of cosh(MATRIX*t) should be no problem. However, I wonder if
> there is any way of taking into account the sqrt-operation on the matrix
> as well.

Can't say in the context above, however the answer may lie within the
subject of matrix fcns. In a nutshell, if a fcn f(x) is defined on the
spectrum of A, then there exists a matrix valued fcn f(A) as well. To
get started, see:

"The numerical treatment of the vertically averaged pdes for a
well-mixed estuary by the multiplicative integral and transcendental
fcns of matrices method", N. Petrakopoulos, Proceedings of the SCS,
Reno, Nevada, 1985

--
Dr.B.Voh
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