[Beignet] [PATCH] fix built-in function "fast_normalize"

[Xing, Homer]

This info is got from the source code of a non-public test case.

In OpenCL spec, this info is not clearly defined. The spec defines the output of "normalize" but does not define the output of "fast_normalize" when the input is NaN.

Homer

-----Original Message-----
From: Zhigang Gong [mailto:zhigang.gong at linux.intel.com] 
Sent: Tuesday, October 29, 2013 10:50 AM
To: Xing, Homer
Cc: Lu, Guanqun; beignet at lists.freedesktop.org
Subject: Re: [Beignet] [PATCH] fix built-in function "fast_normalize"

Ok,
Could you give a pointer to "The input of "Fast_normalize" cannot be NaN."?
in the opencl spec. Thanks.

On Tue, Oct 29, 2013 at 03:01:24AM +0000, Xing, Homer wrote:
> No. 
> 
> The input of "Fast_normalize" cannot be NaN.
> 
> Homer Hsing
> 
> -----Original Message-----
> From: Zhigang Gong [mailto:zhigang.gong at linux.intel.com]
> Sent: Tuesday, October 29, 2013 10:26 AM
> To: Xing, Homer
> Cc: Lu, Guanqun; beignet at lists.freedesktop.org
> Subject: Re: [Beignet] [PATCH] fix built-in function "fast_normalize"
> 
> Homer,
> 
> Do you want to submit a new version of patch to fix this issue? Thanks.
> 
> On Mon, Oct 28, 2013 at 02:49:30AM +0000, Xing, Homer wrote:
> > I think the same as you. You should assume that if x is NaN, then the result should be a vector full of NaNs.
> > 
> > Homer Hsing
> > 
> > -----Original Message-----
> > From: Lu, Guanqun
> > Sent: Monday, October 28, 2013 10:41 AM
> > To: Xing, Homer; beignet at lists.freedesktop.org
> > Subject: RE: [Beignet] [PATCH] fix built-in function "fast_normalize"
> > 
> > hi homer,
> > 
> > how about if x is NaN, according to the opencl-1.2 spec.
> > 
> >   "normalize ( v ) returns a vector full of NaNs if any element is a NaN."
> > 
> > so i would assume that if x is NaN, the result should be NaN. HOw do you think?
> > 
> > 
> > --guanqun
> > 
> > 
> > 
> > > -----Original Message-----
> > > From: beignet-bounces+guanqun.lu=intel.com at lists.freedesktop.org
> > > [mailto:beignet-bounces+guanqun.lu=intel.com at lists.freedesktop.org
> > > ]
> > > On Behalf Of Homer Hsing
> > > Sent: Monday, October 28, 2013 9:03 AM
> > > To: beignet at lists.freedesktop.org
> > > Subject: [Beignet] [PATCH] fix built-in function "fast_normalize"
> > > 
> > > if the parameter is zero, then return zero if the parameter is 
> > > positive, then return 1.
> > > for other cases, return -1.
> > > 
> > > Signed-off-by: Homer Hsing <homer.xing at intel.com>
> > > ---
> > >  backend/src/ocl_stdlib.tmpl.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/backend/src/ocl_stdlib.tmpl.h 
> > > b/backend/src/ocl_stdlib.tmpl.h index a3bf0a0..38d1ab0 100644
> > > --- a/backend/src/ocl_stdlib.tmpl.h
> > > +++ b/backend/src/ocl_stdlib.tmpl.h
> > > @@ -1779,7 +1779,7 @@ INLINE_OVERLOADABLE float 
> > > fast_distance(float x, float y) { return length(x-y);  
> > > INLINE_OVERLOADABLE float
> > > fast_distance(float2 x, float2 y) { return length(x-y); } 
> > > INLINE_OVERLOADABLE float fast_distance(float3 x, float3 y) { 
> > > return length(x-y); }  INLINE_OVERLOADABLE float 
> > > fast_distance(float4 x,
> > > float4 y) { return length(x-y); } -INLINE_OVERLOADABLE float 
> > > fast_normalize(float x) { return 1.f; }
> > > +INLINE_OVERLOADABLE float fast_normalize(float x) { return x > 0 ? 
> > > +1.f : (x <
> > > 0 ? -1.f : 0.f); }
> > >  INLINE_OVERLOADABLE float2 fast_normalize(float2 x) { return x * 
> > > rsqrt(dot(x, x)); }  INLINE_OVERLOADABLE float3
> > > fast_normalize(float3
> > > x) { return x * rsqrt(dot(x, x)); }  INLINE_OVERLOADABLE float4
> > > fast_normalize(float4 x) { return x * rsqrt(dot(x, x)); }
> > > --
> > > 1.8.3.2
> > > 
> > > _______________________________________________
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