[vector] Is Mask inverted in XXXVector.xxxAll(Mask<>)?

[Vladimir Ivanov]

On 25/03/2019 09:13, Deshpande, Vivek R wrote:
> Hi Vladimir
> 
> Yes you are right the tests for masked reductions are missing.
> We can add those with our development progress.

Sounds good, filed https://bugs.openjdk.java.net/browse/JDK-8221429 to 
track it.

Best regards,
Vladimir Ivanov

> -----Original Message-----
> From: Vladimir Ivanov [mailto:vladimir.x.ivanov at oracle.com]
> Sent: Friday, March 22, 2019 4:45 PM
> To: Deshpande, Vivek R <vivek.r.deshpande at intel.com>; panama-dev at openjdk.java.net
> Subject: Re: [vector] Is Mask inverted in XXXVector.xxxAll(Mask<>)?
> 
> Another interesting question is: why the tests haven't caught it?
> 
> It seems like masked reductions aren't tested at all.
> 
> Best regards,
> Vladimir Ivanov
> 
> On 22/03/2019 12:22, Deshpande, Vivek R wrote:
>> Thanks Vladimir
>>
>> I will go ahead push the patch for now to resolve the bug.
>> As you said, we should think on improving the naming/ Javadoc in coming time.
>>
>> Regards,
>> Vivek
>>
>> -----Original Message-----
>> From: Vladimir Ivanov [mailto:vladimir.x.ivanov at oracle.com]
>> Sent: Thursday, March 21, 2019 5:47 PM
>> To: Deshpande, Vivek R <vivek.r.deshpande at intel.com>;
>> panama-dev at openjdk.java.net
>> Subject: Re: [vector] Is Mask inverted in XXXVector.xxxAll(Mask<>)?
>>
>>
>>> Could you please review the patch for the fix:
>>> http://cr.openjdk.java.net/~vdeshpande/VectorAPI/8221176/webrev.00/
>>
>> Looks good.
>>
>>    From API perspective, what do people think about Vector.blend() as it is specified now?
>>
>> It looks naturally when you compare it to other masked operations:
>>
>>      a.op(m)       == (m_i ? op(a_i)     : a_i)
>>
>>      a.op(b, m)    == (m_i ? op(a_i,b_i) : a_i)
>>
>>      a.blend(b, m) == (m_i ? b_i         : a_i) // ok
>>
>> but it's confusing (at least, to me) when you see it alone:
>>
>>      a.blend(b, m);
>>
>> I read it as 'blend(a,b,m)' and the first interpretation usually is opposite to the actual behavior.
>>
>> Maybe it can be improved by different naming?
>>
>> Best regards,
>> Vladimir Ivanov
>>
>>> -----Original Message-----
>>> From: Vladimir Ivanov [mailto:vladimir.x.ivanov at oracle.com]
>>> Sent: Wednesday, March 20, 2019 2:48 PM
>>> To: Deshpande, Vivek R <vivek.r.deshpande at intel.com>; Lev Serebryakov
>>> <lev at serebryakov.spb.ru>; panama-dev at openjdk.java.net
>>> Subject: Re: [vector] Is Mask inverted in XXXVector.xxxAll(Mask<>)?
>>>
>>>
>>>> It is selecting values from the broadcasted vector from base scalar
>>>> value(used as starting point) based on the mask, instead of the vector on which we want to reduce.
>>>> I think the arguments to blend  passed should be interchanged.
>>>
>>> Yes, it agrees with my analysis of the problem (added to JDK-8221176).
>>>
>>> Best regards,
>>> Vladimir Ivanov
>>>
>>>> -----Original Message-----
>>>> From: panama-dev [mailto:panama-dev-bounces at openjdk.java.net] On
>>>> Behalf Of Vladimir Ivanov
>>>> Sent: Wednesday, March 20, 2019 2:21 PM
>>>> To: Lev Serebryakov <lev at serebryakov.spb.ru>;
>>>> panama-dev at openjdk.java.net
>>>> Subject: Re: [vector] Is Mask inverted in XXXVector.xxxAll(Mask<>)?
>>>>
>>>> Thanks for the report, Lev!
>>>>
>>>> Yes, it's a bug. Filed
>>>> https://bugs.openjdk.java.net/browse/JDK-8221176
>>>>
>>>> Best regards,
>>>> Vladimir Ivanov
>>>>
>>>> On 19/03/2019 09:54, Lev Serebryakov wrote:
>>>>>
>>>>>       This code gives me 100.0f and not expected 10.0f (Preferred
>>>>> Spices in
>>>>> 256 on my system, as I don't have AVX-512):
>>>>>
>>>>> FloatVector.FloatSpecies PFS = FloatVector.preferredSpecies();
>>>>> FloatVector.Mask m = FloatVector.maskFromValues(PFS,
>>>>>        true, false, true, false, true, false, true, false );
>>>>> FloatVector v = FloatVector.fromArray(PFS, new float[]
>>>>>         { 1.0f, 10.0f, 2.0f, 20.0f, 3.0f, 30.0f, 4.0f, 40.0f }, 0 );
>>>>> float sum = v.addAll(m);
>>>>>
>>>>>
>>>>>       Same problem with `mulAll()`.
>>>>>