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Subject: Re: [boost] different matrix library?
From: DE (satan66613_at_[hidden])
Date: 2009-08-20 11:41:36


a note on band matrix arithmetic

band matrix is square
band width is a number of diagonals wich contain numbers
band width is always odd (1 main diag + m lower diags + m upper diags)
so for a matrix N by N there can be a maximum of (2*n - 1) diagonals
(in this case it is an ordinary dense matrix with all diags filled)

only equally sized matrices can be involved in operations (+-*)
operations on band matrices yield band matrices

+- operations on two matrices with bandwidths w1 and w2 evidently
yield a band matrix with width = max(w1, w2)

multiplication of w1 and w2 widths matrices yields a matrix with
width = (w1 + w2 - 1)

so i guess there must be a specialization for handling such cases
and more: a band matrix can be also symmetric (i don't know yet if
this is redundant)

-- 
Pavel

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