[boost] Re: Re: Re: Dimensional Analysis

From: Robert Ramey (ramey_at_[hidden])
Date: 2005-02-02 15:48:06

At first I didn't understand this. But upon a little reflection  I think it
is a very interesting idea.  If Dimensional analysis were built on top of
this, odd ball cases such as "nanovolts per sqrt(Hz)" could be handled as
specializations of <T,X1> op <T,X2> while default dimensional analysis would
be used it implement the default cases.

Robert Ramey

Matt Austern wrote:
> There's actually something even lower level than a dimension library.
> In essence, what we've got is:
>  - We're generalizing the notion of an arithmetic type T to a type of
> the form <T,X>, where X is some sort of tag.
>  - For any X1 and X2 and any arithmetic operation 'op', we have rules
> for whether <T,X1> op <T,X2> is well defined.  If it is then the
> result is tagged as <T,X3>, and we have rules to determine X3 in terms
> of X1, X2, and op.
>
> All of the knowledge about how to represent dimensional systems (mpl
> vectors, compile-time fractions, etc.) is higher level than this.