Re: [boost] [ublas] bugfix for matrix operation /

Subject: Re: [boost] [ublas] bugfix for matrix operation /
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2013-04-17 12:06:35

On Wed, Apr 17, 2013 at 7:08 AM, Mario Mulansky <mario.mulansky_at_[hidden]>wrote:

> On Tuesday, April 16, 2013 08:16:57 PM Steven Watanabe wrote:
> > AMDG
> >
> > On 04/16/2013 07:20 PM, Mario Mulansky wrote:
> > > Hi,
> > >
> > > I wanted to add an elementwise divide operations for ublas matrices
> using
> > > operator /
> >
> > I don't think that's such a great idea.
> > Using regular operators for elementwise
> > operations is likely to be surprising.
> > i.e.  if you can do (A / B) you should
> > be able to do (A * B) as well, and it
> > you be the inverse of A / B.  But
> > multiplication is defined for matrices
> > and is *not* an elementwise operation.
> > There is no way to define this that
> > won't surprise someone.  There's a
> > good reason why uBlas doesn't provide
> > these operators already and why MATLAB
> > has a separate set of operators for
> > elementwise operations.
>
> uh wait, i dont want to add this operator to ublas. I need it within odeint
> and it would be part of some ublas_extension.hpp in odeint, it would be
> merely
> an implementation detail no user would encounter.

[...]

If no user would encounter it, why don't you just define and use a free
function elementwise_divide? Why does it have to be named operator/?

- Jeff