[Beignet] [PATCH] [PATCH]GBE: improve precision of tanh
Yang, Rong R
rong.r.yang at intel.com
Sun Dec 22 18:44:27 PST 2013
Test pass with multi-thread disabled. Thanks.
-----Original Message-----
From: beignet-bounces at lists.freedesktop.org [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of Lv Meng
Sent: Friday, December 20, 2013 10:37 AM
To: beignet at lists.freedesktop.org
Cc: Lv, Meng
Subject: [Beignet] [PATCH] [PATCH]GBE: improve precision of tanh
Signed-off-by: Lv Meng <meng.lv at intel.com>
---
backend/src/ocl_stdlib.tmpl.h | 39 +++++++++++++++++++++++++++++++++++----
1 file changed, 35 insertions(+), 4 deletions(-)
diff --git a/backend/src/ocl_stdlib.tmpl.h b/backend/src/ocl_stdlib.tmpl.h index da8b411..4c14f63 100755
--- a/backend/src/ocl_stdlib.tmpl.h
+++ b/backend/src/ocl_stdlib.tmpl.h
@@ -1662,10 +1662,6 @@ INLINE_OVERLOADABLE float sincos(float x, private float *cosval) { BODY; } INLINE_OVERLOADABLE float __gen_ocl_internal_cosh(float x) {
return (1 + native_exp(-2 * x)) / (2 * native_exp(-x)); } -INLINE_OVERLOADABLE float __gen_ocl_internal_tanh(float x) {
- float y = native_exp(-2 * x);
- return (1 - y) / (1 + y);
-}
INLINE float __gen_ocl_asin_util(float x) {
/*
@@ -2209,6 +2205,41 @@ INLINE_OVERLOADABLE float __gen_ocl_internal_sinh(float x){
return x*shuge;
}
+INLINE_OVERLOADABLE float __gen_ocl_internal_tanh(float x) {
+ //float y = native_exp(-2 * x);
+ //return (1 - y) / (1 + y);
+ float one=1.0, two=2.0, tiny = 1.0e-30;
+ float t,z;
+ int jx,ix;
+ GEN_OCL_GET_FLOAT_WORD(jx,x);
+ ix = jx&0x7fffffff;
+ /* x is INF or NaN */
+ if(ix>=0x7f800000) {
+ if (jx>=0)
+ return one/x+one; /* tanh(+-inf)=+-1 */
+ else
+ return one/x-one; /* tanh(NaN) = NaN */
+ }
+
+ if (ix < 0x41b00000) { /* |x|<22 */
+ if (ix == 0)
+ return x; /* x == +-0 */
+ if (ix<0x24000000) /* |x|<2**-55 */
+ return x*(one+x); /* tanh(small) = small */
+ if (ix>=0x3f800000) { /* |x|>=1 */
+ t = __gen_ocl_internal_expm1(two*__gen_ocl_internal_fabs(x));
+ z = one - two/(t+two);
+ } else {
+ t = __gen_ocl_internal_expm1(-two*__gen_ocl_internal_fabs(x));
+ z= -t/(t+two);
+ }
+ } else { /* |x| > 22, return +-1 */
+ z = one - tiny; /* raised inexact flag */
+ }
+ return (jx>=0)? z: -z;
+}
+
+
// TODO use llvm intrinsics definitions #define cos native_cos #define cospi __gen_ocl_internal_cospi
--
1.7.10.4
_______________________________________________
Beignet mailing list
Beignet at lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/beignet
More information about the Beignet
mailing list