[Libva] [PATCH v2] test: use valarray for raw image comparison

[Eoff, Ullysses A]

Ah, I overlooked the data types on my first review.  Indeed it's important to take it into account when diff'ing.  This is why they were being cast to "int" previously to calculate the diff.

On my system /dev/urandom seems to work (i.e. not all zeros).  But I agree, let's drop it since it does not seem to be very uniform.

This version looks much better to me.

Thanks,

U. Artie

> -----Original Message-----
> From: Libva [mailto:libva-bounces at lists.freedesktop.org] On Behalf Of Scott D Phillips
> Sent: Monday, October 17, 2016 1:01 PM
> To: libva at lists.freedesktop.org
> Subject: [Libva] [PATCH v2] test: use valarray for raw image comparison
> 
> std::valarray can fuse elementwise operations across arrays for
> more efficient comparison.
> 
> Signed-off-by: Scott D Phillips <scott.d.phillips at intel.com>
> ---
> Changes since v1:
> - s/width * height/sizes/
> - Added another array 'signs' which ensures that 0 and 255 never
>   compare as separated by one.
> 
> Also, the patch about /dev/urandom actually was accidentally
> generating all zeroes instead of random data.  Fixing the bug
> there eliminated the performance gain, so I'm dropping that patch
> from the series.
> 
>  test/i965_jpeg_encode_test.cpp | 29 +++++++++++++----------------
>  1 file changed, 13 insertions(+), 16 deletions(-)
> 
> diff --git a/test/i965_jpeg_encode_test.cpp b/test/i965_jpeg_encode_test.cpp
> index 29c14dc..173cd93 100644
> --- a/test/i965_jpeg_encode_test.cpp
> +++ b/test/i965_jpeg_encode_test.cpp
> @@ -30,6 +30,7 @@
>  #include <cstring>
>  #include <memory>
>  #include <tuple>
> +#include <valarray>
> 
>  namespace JPEG {
>  namespace Encode {
> @@ -400,23 +401,19 @@ protected:
>          ASSERT_EQ(expect->height(), image.height);
>          ASSERT_NO_FAILURE(uint8_t *data = mapBuffer<uint8_t>(image.buf));
> 
> -        auto isClose = [](const uint8_t& a, const uint8_t& b) {
> -            return std::abs(int(a)-int(b)) <= 2;
> -        };
> -
>          for (size_t i(0); i < image.num_planes; ++i) {
> -            size_t w = expect->widths[i];
> -            size_t h = expect->heights[i];
> -
> -            const ByteData::value_type *source = expect->plane(i);
> -            const uint8_t *result = data + image.offsets[i];
> -            ASSERT_GE(image.pitches[i], w);
> -            for (size_t r(0); r < h; ++r) {
> -                EXPECT_TRUE(std::equal(result, result + w, source, isClose))
> -                    << "Byte(s) mismatch in plane " << i << " row " << r;
> -                source += w;
> -                result += image.pitches[i];
> -            }
> +            ASSERT_GE(image.pitches[i], expect->widths[i]);
> +            std::valarray<uint8_t> source(expect->plane(i), expect->sizes[i]);
> +            std::gslice result_slice(0, {expect->heights[i], expect->widths[i]},
> +                {image.pitches[i], 1});
> +            std::valarray<uint8_t> result = std::valarray<uint8_t>(
> +                data + image.offsets[i],
> +                image.pitches[i] * expect->heights[i])[result_slice];
> +            std::valarray<uint8_t> signs(1, result.size());
> +            signs[result > source] = -1;
> +            ASSERT_EQ(source.size(), result.size());
> +            EXPECT_TRUE((source * signs - result * signs).max() <= 2)
> +                << "Byte(s) mismatch in plane " << i;
>          }
> 
>          unmapBuffer(image.buf);
> --
> 2.7.4
> 
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