Re: [boost] 2D Matrix

From: james.jones_at_[hidden]
Date: 2006-11-08 15:45:13

From: Jason Kraftcheck <kraftche_at_[hidden]>
> The TVMET library seems to define implementations of every libm function for
> matrices (sin, pow, etc.).  It implements them by applying the equivalent scalar
> function to each matrix element.  This kind of stuff results in a lot of noise
> in the library, is unlikely to be very useful, and the theoretical meaning of
> these operations is dubious.  For example, mathematically, pow( M, 3 ) for a
> matrix M means M * M * M, which is not the same as cubing each element of M.

Worse still, there is a mathematical definition for exp(M), sin(M), etc., involving power series expansion, which is used from time to time. So defining it differently in a library is quite misleading. It's sometimes useful to apply a function to every element of a matrix, but this should be done via an analog of for_each (IMO).

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