[Beignet] [PATCH 4/6] GBE: fix bug in lgamma.

Zhigang Gong zhigang.gong at intel.com
Tue Nov 4 21:41:14 PST 2014


tgamma is actually lgamma, a related but very different function.

This patch is from:
https://bugs.debian.org/cgi-bin/bugreport.cgi?msg=5;filename=Fix-pow-erf-tgamma.patch;att=3;bug=768090

Signed-off-by: Zhigang Gong <zhigang.gong at intel.com>
---
 backend/src/libocl/tmpl/ocl_math.tmpl.cl | 190 ++-----------------------------
 1 file changed, 7 insertions(+), 183 deletions(-)

diff --git a/backend/src/libocl/tmpl/ocl_math.tmpl.cl b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
index 591e5a9..2d12426 100644
--- a/backend/src/libocl/tmpl/ocl_math.tmpl.cl
+++ b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
@@ -1010,189 +1010,6 @@ OVERLOADABLE float __gen_ocl_internal_sinpi(float x) {
 
 }
 
-OVERLOADABLE float tgamma(float x) {
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunPro, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-  float pi = 3.1415927410e+00,
-    a0 = 7.7215664089e-02,
-    a1 = 3.2246702909e-01,
-    a2 = 6.7352302372e-02,
-    a3 = 2.0580807701e-02,
-    a4 = 7.3855509982e-03,
-    a5 = 2.8905137442e-03,
-    a6 = 1.1927076848e-03,
-    a7 = 5.1006977446e-04,
-    a8 = 2.2086278477e-04,
-    a9 = 1.0801156895e-04,
-    a10 = 2.5214456400e-05,
-    a11 = 4.4864096708e-05,
-    tc = 1.4616321325e+00,
-    tf = -1.2148628384e-01,
-    tt = 6.6971006518e-09,
-    t0 = 4.8383611441e-01,
-    t1 = -1.4758771658e-01,
-    t2 = 6.4624942839e-02,
-    t3 = -3.2788541168e-02,
-    t4 = 1.7970675603e-02,
-    t5 = -1.0314224288e-02,
-    t6 = 6.1005386524e-03,
-    t7 = -3.6845202558e-03,
-    t8 = 2.2596477065e-03,
-    t9 = -1.4034647029e-03,
-    t10 = 8.8108185446e-04,
-    t11 = -5.3859531181e-04,
-    t12 = 3.1563205994e-04,
-    t13 = -3.1275415677e-04,
-    t14 = 3.3552918467e-04,
-    u0 = -7.7215664089e-02,
-    u1 = 6.3282704353e-01,
-    u2 = 1.4549225569e+00,
-    u3 = 9.7771751881e-01,
-    u4 = 2.2896373272e-01,
-    u5 = 1.3381091878e-02,
-    v1 = 2.4559779167e+00,
-    v2 = 2.1284897327e+00,
-    v3 = 7.6928514242e-01,
-    v4 = 1.0422264785e-01,
-    v5 = 3.2170924824e-03,
-    s0 = -7.7215664089e-02,
-    s1 = 2.1498242021e-01,
-    s2 = 3.2577878237e-01,
-    s3 = 1.4635047317e-01,
-    s4 = 2.6642270386e-02,
-    s5 = 1.8402845599e-03,
-    s6 = 3.1947532989e-05,
-    r1 = 1.3920053244e+00,
-    r2 = 7.2193557024e-01,
-    r3 = 1.7193385959e-01,
-    r4 = 1.8645919859e-02,
-    r5 = 7.7794247773e-04,
-    r6 = 7.3266842264e-06,
-    w0 = 4.1893854737e-01,
-    w1 = 8.3333335817e-02,
-    w2 = -2.7777778450e-03,
-    w3 = 7.9365057172e-04,
-    w4 = -5.9518753551e-04,
-    w5 = 8.3633989561e-04,
-    w6 = -1.6309292987e-03;
-  float t, y, z, nadj, p, p1, p2, p3, q, r, w;
-  int i, hx, ix;
-  nadj = 0;
-  hx = *(int *) (&x);
-  ix = hx & 0x7fffffff;
-  if (ix >= 0x7f800000)
-    return x * x;
-  if (ix == 0)
-    return INFINITY;
-  if (ix < 0x1c800000) {
-    if (hx < 0) {
-      return - native_log(-x);
-    } else
-      return - native_log(x);
-  }
-  if (hx < 0) {
-    if (ix >= 0x4b000000)
-      return INFINITY;
-    t = __gen_ocl_internal_sinpi(x);
-    if (__gen_ocl_fabs(t) < 1e-8f)
-      return INFINITY;
-    nadj = native_log(M_PI_F / __gen_ocl_fabs(t * x));
-    x = -x;
-  }
-
-  if (ix == 0x3f800000 || ix == 0x40000000)
-    r = 0;
-  else if (ix < 0x40000000) {
-    if (ix <= 0x3f666666) {
-      r = - native_log(x);
-      if (ix >= 0x3f3b4a20) {
-        y = 1 - x;
-        i = 0;
-      } else if (ix >= 0x3e6d3308) {
-        y = x - (tc - 1);
-        i = 1;
-      } else {
-        y = x;
-        i = 2;
-      }
-    } else {
-      r = 0;
-      if (ix >= 0x3fdda618) {
-        y = 2 - x;
-        i = 0;
-      } else if (ix >= 0x3F9da620) {
-        y = x - tc;
-        i = 1;
-      } else {
-        y = x - 1;
-        i = 2;
-      }
-    }
-    switch (i) {
-    case 0:
-      z = y * y;
-      p1 = a0 + z * (a2 + z * (a4 + z * (a6 + z * (a8 + z * a10))));
-      p2 = z * (a1 + z * (a3 + z * (a5 + z * (a7 + z * (a9 + z * a11)))));
-      p = y * p1 + p2;
-      r += (p - .5f * y);
-      break;
-    case 1:
-      z = y * y;
-      w = z * y;
-      p1 = t0 + w * (t3 + w * (t6 + w * (t9 + w * t12)));
-      p2 = t1 + w * (t4 + w * (t7 + w * (t10 + w * t13)));
-      p3 = t2 + w * (t5 + w * (t8 + w * (t11 + w * t14)));
-      p = z * p1 - (tt - w * (p2 + y * p3));
-      r += (tf + p);
-      break;
-    case 2:
-      p1 = y * (u0 + y * (u1 + y * (u2 + y * (u3 + y * (u4 + y * u5)))));
-      p2 = 1 + y * (v1 + y * (v2 + y * (v3 + y * (v4 + y * v5))));
-      r += (-.5f * y + p1 / p2);
-    }
-  } else if (ix < 0x41000000) {
-    i = x;
-    t = 0;
-    y = x - i;
-    p = y*(s0+y*(s1+y*(s2+y*(s3+y*(s4+y*(s5+y*s6))))));
-    q = 1 + y * (r1 + y * (r2 + y * (r3 + y * (r4 + y * (r5 + y * r6)))));
-    r = .5f * y + p / q;
-    z = 1;
-    switch (i) {
-    case 7:
-      z *= (y + 6.f);
-    case 6:
-      z *= (y + 5.f);
-    case 5:
-      z *= (y + 4.f);
-    case 4:
-      z *= (y + 3.f);
-    case 3:
-      z *= (y + 2.f);
-      r += native_log(z);
-      break;
-    }
-  } else if (ix < 0x5c800000) {
-    t = native_log(x);
-    z = 1 / x;
-    y = z * z;
-    w = w0 + z * (w1 + y * (w2 + y * (w3 + y * (w4 + y * (w5 + y * w6)))));
-    r = (x - .5f) * (t - 1) + w;
-  } else
-    r = x * (native_log(x) - 1);
-  if (hx < 0)
-    r = nadj - r;
-  return r;
-}
-
 OVERLOADABLE float lgamma(float x) {
 /*
  * ====================================================
@@ -2150,6 +1967,13 @@ OVERLOADABLE float __gen_ocl_internal_exp(float x) {
   }
 }
 
+INLINE_OVERLOADABLE float tgamma(float x) {
+  float y;
+  int s;
+  y=lgamma_r(x,&s);
+  return __gen_ocl_internal_exp(y)*s;
+}
+
 /* erf,erfc from glibc s_erff.c -- float version of s_erf.c.
  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian at cygnus.com.
  */
-- 
1.8.3.2



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