Re: [ViennaCL-devel] Efficient unary operation

[Charles D. <cde...@gm...>]

That works perfectly, thanks Karl.

Regards,
Charles

On Wed, Nov 23, 2016 at 2:53 PM, Karl Rupp <ru...@iu...> wrote:

> Hi Charles,
>
> Right now, if I want to take the negative of every element in a matrix I
>> end up doing the following:
>>
>> // previously assigned
>> viennacl::matrix<T> vcl_A;
>>
>> // matrix of zeros to subtract from
>> viennacl::matrix<T> vcl_Z =
>> viennacl::zero_matrix<T>(vcl_A.size1(),vcl_A.size2());
>>
>> // subtract in-place
>> vcl_Z -= vcl_A;
>> vcl_A = vcl_Z;
>>
>> Is there a more efficient way to approach this?  Allocating an
>> additional entire matrix is proving quite wasteful in some of my
>> benchmarks.
>>
>
> What about just
>
> vcl_A = T(-1) * vcl_A;
>
> ? This is 'inplace' as requested :-)
>
> Best regards,
> Karli
>
>
>