[Beignet] [PATCH 2/4] Backend: Optimization internal math, lower polynomials

[Lupescu, Grigore]

I've submited a new patchset [1] to address the issues related to lgamma and lgamma_r.
The problem should now be fixed - all tests defined in utest and conformance are passing on BDW.

If all tests pass on other configurations as well I think we could merge this patchset [1] to master.

In addition to this patchset [1] the AMD CLC functions patch [2] can be further used to improve - given no licensing issues.

[1] https://lists.freedesktop.org/archives/beignet/2016-July/007800.html
[2] https://lists.freedesktop.org/archives/beignet/2016-May/007585.html

-----Original Message-----
From: Song, Ruiling 
Sent: Friday, July 22, 2016 11:31 AM
To: Lupescu, Grigore <grigore.lupescu at intel.com>; beignet at lists.freedesktop.org
Subject: RE: [Beignet] [PATCH 2/4] Backend: Optimization internal math, lower polynomials

Hi Grigore,

After applying the patchset. Looks like some utest failed.
These failure relate to gamma functions.
Ocl spec requires tgamma() should be < 16ulp.
Although ocl spec does not give out ulp for lgamma and lgamma_r.
I think if we can make it under 16ulp. That is acceptable.
Please help to take a look. It may relate to decreasing the polynomial grade.
The utest may be also not very correct, you can fix them.

builtin_lgamma_float()    [FAILED]
    Error: input_data1:3.140000e+00  -> gpu:8.260892e-01  cpu:8.261388e-01 diff:4.959106e-05 expect:2.384186e-07

  at file /home/ruilings/workspace/beignet/utests/generated/builtin_lgamma_float.cpp, function builtin_lgamma_float, line 123
builtin_lgamma_float2()    [FAILED]
    Error: input_data1:3.140000e+00  -> gpu:8.260892e-01  cpu:8.261388e-01 diff:4.959106e-05 expect:2.384186e-07

  at file /home/ruilings/workspace/beignet/utests/generated/builtin_lgamma_float2.cpp, function builtin_lgamma_float2, line 123
builtin_lgamma_float4()    [FAILED]
    Error: input_data1:3.140000e+00  -> gpu:8.260892e-01  cpu:8.261388e-01 diff:4.959106e-05 expect:2.384186e-07

  at file /home/ruilings/workspace/beignet/utests/generated/builtin_lgamma_float4.cpp, function builtin_lgamma_float4, line 123
builtin_lgamma_float8()    [FAILED]
    Error: input_data1:3.140000e+00  -> gpu:8.260892e-01  cpu:8.261388e-01 diff:4.959106e-05 expect:2.384186e-07

  at file /home/ruilings/workspace/beignet/utests/generated/builtin_lgamma_float8.cpp, function builtin_lgamma_float8, line 123
builtin_lgamma_float16()    [FAILED]
    Error: input_data1:3.140000e+00  -> gpu:8.260892e-01  cpu:8.261388e-01 diff:4.959106e-05 expect:2.384186e-07

  at file /home/ruilings/workspace/beignet/utests/generated/builtin_lgamma_float16.cpp, function builtin_lgamma_float16, line 123
builtin_lgamma()0.094000 2.317156 2.316127
    [FAILED]
    Error: 0
  at file /home/ruilings/workspace/beignet/utests/builtin_lgamma.cpp, function builtin_lgamma, line 33
builtin_lgamma_r()0.094000 2.317156 2.316127
    [FAILED]
    Error: 0
  at file /home/ruilings/workspace/beignet/utests/builtin_lgamma_r.cpp, function builtin_lgamma_r, line 38
builtin_tgamma()-3.820000 0.319208 0.319208
    [FAILED]
    Error: 0
  at file /home/ruilings/workspace/beignet/utests/builtin_tgamma.cpp, function builtin_tgamma, line 50

Thanks!
Ruiling

> -----Original Message-----
> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf 
> Of Grigore Lupescu
> Sent: Tuesday, June 28, 2016 3:04 AM
> To: beignet at lists.freedesktop.org
> Subject: [Beignet] [PATCH 2/4] Backend: Optimization internal math, 
> lower polynomials
> 
> From: Grigore Lupescu <grigore.lupescu at intel.com>
> 
> Use lower grade polynomials for approximations, keep conformance passing.
> 
> LOG	Use polynomial grade 4 (was 7)
> LOG2	Use polynomial grade 4 (was 7)
> SIN	Use polynomial grade 4 (was 6)
> COS	Use polynomial grade 3 (was 6)
> TANF	Use polynomial grade 7 (was 12)
> GAMMA	Use polynomial grade 3 (was 12)
> GAMMA_R Use polynomial grade 3 (was 12)
> LOG1P	Use polynomial grade 4 (was 7)
> ASIN	Use polynomial grade 4 (was 5)
> ATAN	Use polynomial grade 6 (was 10)
> EXP	Use polynomial grade 2 (was 5)
> EXPM1	Use polynomial grade 3 (was 5)
> POW	Use polynomial grade 2 (was 6)
> POWN	Use polynomial grade 2 (was 6)
> 
> Signed-off-by: Grigore Lupescu <grigore.lupescu at intel.com>
> ---