This is great news and will automatically boost the performance of all
our ALS-based recommenders which are all using QRDecomposition internally.
On 28.01.2013 04:02, Ted Dunning wrote:
> Did that.
>
> You are right. The QRD in mahout is abysmally slow. I wrote a new version
> on the airplane that seems to be about 10x faster and still jsut about as
> accurate (and vastly simpler). I will put up some tests and a patch in the
> next week or so.
>
> On Thu, Jan 24, 2013 at 4:55 PM, Ted Dunning <ted.dunn...@gmail.com> wrote:
>
>> Hmph. That suggests to me that I need to rewrite our QRDecomposition.
>>
>>
>> On Thu, Jan 24, 2013 at 8:27 AM, Ying Liao <yliao...@gmail.com> wrote:
>>
>>> Sean suggests "replacing this with a call to the Apache Commons Math
>>> QRDecomposition" and the sloving time is reduced significantly. Thanks.
>>>
>>>
>>> On Wed, Jan 23, 2013 at 5:10 PM, Ted Dunning <ted.dunn...@gmail.com>
>>> wrote:
>>>
>>>> That is a long time for such a small qr decomposition. I wouldn't think
>>>> that the actually solving would add that much time, either.
>>>>
>>>> On Thu, Jan 24, 2013 at 2:00 AM, Ying Liao <yliao...@gmail.com> wrote:
>>>>
>>>>> Hi!
>>>>> The QRDecomposition turns out to be my bottleneck in deploying
>>> ALS-WR. It
>>>>> takes less than a ms to solve X=A^{-1}B when A is 20*20. But it takes
>>>> 55ms
>>>>> per solve when A is 60*60. Is there a different approach to solve
>>> AX=B?
>>>>>
>>>>> Thanks,
>>>>> Ying
>>>>>
>>>>
>>>
>>
>>
>
