Thanks!   ArrayViews does work with axpy!() and does help both with
execution time and memory.

On Tue, May 5, 2015 at 7:33 PM, Patrick O'Leary <[email protected]>
wrote:

> On Tuesday, May 5, 2015 at 9:06:50 PM UTC-5, Christian Peel wrote:
>>
>> I have a question for the BLAS gurus:  I can use the BLAS function
>>    B[:,lx] = axpy!(-mu, B[:,k], B[:,lx])
>> to accelerate the code
>>   B[:,lx]   = B[:,lx]   - mu * B[:,k]
>> but what I wanted to do was simply
>>   axpy!(-mu, B[:,k], B[:,lx])
>> I guess that there is some pass-by-value problem that makes the in-place
>> nature of axpy! not work on columns of a matrix.  Any suggestions for
>> improving this?  See line  47 of
>> https://github.com/christianpeel/LLLplus.jl/blob/master/src/lll.jl for
>> the original code.
>>
>
> The slice operation creates a temporary array, so the copy is mutated,
> then thrown away. I'm not sure if ArrayViews (from ArrayViews.jl) will work
> with axpy!(), but you might want to check.
>



-- 
[email protected]

Reply via email to