[Beignet] [PATCH] add built-in function "atan2"

Zhigang Gong zhigang.gong at linux.intel.com
Wed Sep 11 00:07:08 PDT 2013


Pushed, thanks.

On Wed, Sep 11, 2013 at 06:08:54AM +0000, Yang, Rong R wrote:
> LGTM, test ok, thanks.
> 
> -----Original Message-----
> From: beignet-bounces+rong.r.yang=intel.com at lists.freedesktop.org [mailto:beignet-bounces+rong.r.yang=intel.com at lists.freedesktop.org] On Behalf Of Homer Hsing
> Sent: Thursday, August 29, 2013 1:41 PM
> To: beignet at lists.freedesktop.org
> Subject: [Beignet] [PATCH] add built-in function "atan2"
> 
> also improve the accuracy of built-in function "atan"
> also add a test case
> 
> Signed-off-by: Homer Hsing <homer.xing at intel.com>
> ---
>  backend/src/builtin_vector_proto.def |  3 +--
>  backend/src/ocl_stdlib.tmpl.h        | 29 +++++++++++++++++++++++-
>  kernels/builtin_atan2.cl             |  4 ++++
>  utests/CMakeLists.txt                |  1 +
>  utests/builtin_atan2.cpp             | 43 ++++++++++++++++++++++++++++++++++++
>  5 files changed, 77 insertions(+), 3 deletions(-)  create mode 100644 kernels/builtin_atan2.cl  create mode 100644 utests/builtin_atan2.cpp
> 
> diff --git a/backend/src/builtin_vector_proto.def b/backend/src/builtin_vector_proto.def
> index 2a3daf2..b24e7ea 100644
> --- a/backend/src/builtin_vector_proto.def
> +++ b/backend/src/builtin_vector_proto.def
> @@ -6,8 +6,7 @@ gentype asin (gentype)
>  gentype asinh (gentype)
>  gentype asinpi (gentype x)
>  gentype atan (gentype y_over_x)
> -# XXX atan2 is a builtin function
> -#gentype atan2 (gentype y, gentype x)
> +gentype atan2 (gentype y, gentype x)
>  gentype atanh (gentype)
>  gentype atanpi (gentype x)
>  #gentype atan2pi (gentype y, gentype x) diff --git a/backend/src/ocl_stdlib.tmpl.h b/backend/src/ocl_stdlib.tmpl.h index ac1999d..7f1032f 100644
> --- a/backend/src/ocl_stdlib.tmpl.h
> +++ b/backend/src/ocl_stdlib.tmpl.h
> @@ -1311,7 +1311,13 @@ INLINE_OVERLOADABLE float __gen_ocl_internal_atan(float x) {
>      x = 1 / x;
>      c = -1;
>    }
> -  return a + c * (x - __gen_ocl_pow(x, 3) / 3 + __gen_ocl_pow(x, 5) / 5 - __gen_ocl_pow(x, 7) / 7 + __gen_ocl_pow(x, 9) / 9 - __gen_ocl_pow(x, 11) / 11);
> +  a += c*x;
> +  int i;
> +  int sign;
> +  for(i=3, sign=-1; i<63; i+=2, sign=-sign) {
> +    a += c*sign*__gen_ocl_pow(x,i)/i;
> +  }
> +  return a;
>  }
>  INLINE_OVERLOADABLE float __gen_ocl_internal_atanpi(float x) {
>    return __gen_ocl_internal_atan(x) / M_PI_F; @@ -1338,6 +1344,26 @@ INLINE_OVERLOADABLE float __gen_ocl_internal_erfc(float x) {  // XXX work-around PTX profile  #define sqrt native_sqrt  INLINE_OVERLOADABLE float rsqrt(float x) { return native_rsqrt(x); }
> +INLINE_OVERLOADABLE float __gen_ocl_internal_atan2(float y, float x) {
> +  uint hx = *(uint *)(&x), ix = hx & 0x7FFFFFFF;
> +  uint hy = *(uint *)(&y), iy = hy & 0x7FFFFFFF;
> +  if (ix > 0x7F800000 || iy > 0x7F800000)
> +    return nan(0u);
> +  if (ix == 0) {
> +    if (y > 0)
> +      return M_PI_2_F;
> +    if (y < 0)
> +      return - M_PI_2_F;
> +    return nan(0u);
> +  } else {
> +    float z = __gen_ocl_internal_atan(y / x);
> +    if (x > 0)
> +      return z;
> +    if (y >= 0)
> +      return M_PI_F + z;
> +    return - M_PI_F + z;
> +  }
> +}
>  INLINE_OVERLOADABLE float __gen_ocl_internal_fabs(float x)  { return __gen_ocl_fabs(x); }  INLINE_OVERLOADABLE float __gen_ocl_internal_trunc(float x) { return __gen_ocl_rndz(x); }  INLINE_OVERLOADABLE float __gen_ocl_internal_round(float x) { return __gen_ocl_rnde(x); } @@ -1370,6 +1396,7 @@ INLINE_OVERLOADABLE float __gen_ocl_internal_rint(float x) {  #define tanpi __gen_ocl_internal_tanpi  #define tanh __gen_ocl_internal_tanh  #define atan __gen_ocl_internal_atan
> +#define atan2 __gen_ocl_internal_atan2
>  #define atanpi __gen_ocl_internal_atanpi  #define atanh __gen_ocl_internal_atanh  #define pow powr diff --git a/kernels/builtin_atan2.cl b/kernels/builtin_atan2.cl new file mode 100644 index 0000000..aba73be
> --- /dev/null
> +++ b/kernels/builtin_atan2.cl
> @@ -0,0 +1,4 @@
> +kernel void builtin_atan2(global float *y, global float *x, global 
> +float *dst) {
> +  int i = get_global_id(0);
> +  dst[i] = atan2(y[i], x[i]);
> +};
> diff --git a/utests/CMakeLists.txt b/utests/CMakeLists.txt index 08b4e32..835524d 100644
> --- a/utests/CMakeLists.txt
> +++ b/utests/CMakeLists.txt
> @@ -104,6 +104,7 @@ set (utests_sources
>    compiler_vector_load_store.cpp
>    compiler_cl_finish.cpp
>    get_cl_info.cpp
> +  builtin_atan2.cpp
>    builtin_bitselect.cpp
>    builtin_frexp.cpp
>    builtin_mad_sat.cpp
> diff --git a/utests/builtin_atan2.cpp b/utests/builtin_atan2.cpp new file mode 100644 index 0000000..29dd7b4
> --- /dev/null
> +++ b/utests/builtin_atan2.cpp
> @@ -0,0 +1,43 @@
> +#include <cmath>
> +#include "utest_helper.hpp"
> +
> +void builtin_atan2(void) {
> +	const int n = 1024;
> +	float y[n], x[n];
> +
> +	// Setup kernel and buffers
> +	OCL_CREATE_KERNEL("builtin_atan2");
> +	OCL_CREATE_BUFFER(buf[0], 0, n * sizeof(float), NULL);
> +	OCL_CREATE_BUFFER(buf[1], 0, n * sizeof(float), NULL);
> +	OCL_CREATE_BUFFER(buf[2], 0, n * sizeof(float), NULL);
> +	OCL_SET_ARG(0, sizeof(cl_mem), &buf[0]);
> +	OCL_SET_ARG(1, sizeof(cl_mem), &buf[1]);
> +	OCL_SET_ARG(2, sizeof(cl_mem), &buf[2]);
> +	globals[0] = n;
> +	locals[0] = 16;
> +
> +	OCL_MAP_BUFFER(0);
> +	OCL_MAP_BUFFER(1);
> +	for (int i = 0; i < n; ++i) {
> +		y[i] = ((float*) buf_data[0])[i] = (rand()&255) * 0.01f;
> +		x[i] = ((float*) buf_data[1])[i] = (rand()&255) * 0.01f;
> +	}
> +	OCL_UNMAP_BUFFER(0);
> +	OCL_UNMAP_BUFFER(1);
> +
> +	OCL_NDRANGE(1);
> +
> +	OCL_MAP_BUFFER(2);
> +	float *dst = (float*) buf_data[2];
> +	for (int i = 0; i < n; ++i) {
> +		float cpu = atan2f(y[i], x[i]);
> +		float gpu = dst[i];
> +		if (fabsf(cpu - gpu) >= 1e-2) {
> +			printf("%f %f %f %f\n", y[i], x[i], cpu, gpu);
> +			OCL_ASSERT(0);
> +		}
> +	}
> +	OCL_UNMAP_BUFFER(2);
> +}
> +
> +MAKE_UTEST_FROM_FUNCTION (builtin_atan2);
> --
> 1.8.1.2
> 
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