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Subject: Re: [boost] [ublas] bugfix for matrix operation /
From: Mario Mulansky (mario.mulansky_at_[hidden])
Date: 2013-04-20 13:02:57

On Tuesday, April 16, 2013 08:16:57 PM Steven Watanabe wrote:
> 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.

So here's the patch I would like to be applied to ublas. As I said, it's
almost trivial and would allow to add matrix-matrix operator/ for those who
want it. Is it possible to have that added to ublas?

Best, Mario

> > Unfortunately, there is operator/ defined for matrix and integral types
> > which hides any other operator definition (matrix_expression.hpp l. 3388)
> > and thus makes it impossible to add this functionality. I would like to
> > add an enable_if statement there that checks if the second argument is
> > convertible to matrix::value_type, as is done for other operators. Who
> > would be responsible for this small change? I can provide the according
> > patch, it's almost trivial.
> In Christ,
> Steven Watanabe
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