From: nicolas <nicolas@git.imagemagick.org>
Date: Mon, 27 Sep 2010 18:56:15 +0000 (+0000)
Subject: use 1.2e-12 relative error version of Sinc for Q64 instead of even higher precision... 
X-Git-Tag: 7.0.1-0~8791
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c2d28f0b9863ca8e0ec5a0d8df90683a1576465d;p=imagemagick

use 1.2e-12 relative error version of Sinc for Q64 instead of even higher precision version
---

diff --git a/ChangeLog b/ChangeLog
index 8bce0e194..cc80f3e68 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,8 @@
   * Simplified the ClampUpAxes code, the use of its outputs, its
     comments, and credited Craig DeForest for the "clamp singular values"
     idea.
+  * No reason to have "insane" precision Sinc in resize.c: Use
+    the 1.2e-12 max. abs. relative error version for Q64 as well as Q32.
 
 2010-09-27  6.6.4-8 Anthony Thyssen <A.Thyssen@griffith...>
   * Replace the blurry "High Quality EWA" technique with a 'Clamped EWA'
diff --git a/magick/resize.c b/magick/resize.c
index cf9953d99..fd24db1e5 100644
--- a/magick/resize.c
+++ b/magick/resize.c
@@ -414,7 +414,7 @@ static MagickRealType SincFast(const MagickRealType x,
     const MagickRealType p = 
       c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*(c6+xx*(c7+xx*(c8+xx*c9))))))));
     return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)*p);
-#elif MAGICKCORE_QUANTUM_DEPTH <= 32
+#else
     /*
       Max. abs. rel. error 1.2e-12 < 1/2^39.
     */
@@ -435,31 +435,6 @@ static MagickRealType SincFast(const MagickRealType x,
     const MagickRealType d4 = 0.114633394140438168641246022557689759090e-6L;
     const MagickRealType q = d0+xx*(d1+xx*(d2+xx*(d3+xx*d4)));
     return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)/q*p);
-#else
-    /*
-      Max. abs. rel. error 2.5e-17 < 1/2^55 if computed with "true"
-      long doubles, 2.6e-14 < 1/2^45 if long doubles are IEEE doubles.
-    */
-    const MagickRealType c0 = 0.173611111111111113332932116053816904714e-2L;
-    const MagickRealType c1 = -0.303723497515718809687399886229022703169e-3L;
-    const MagickRealType c2 = 0.233100817439489606061795544561807507471e-4L;
-    const MagickRealType c3 = -0.103906554814465396861269897523992002705e-5L;
-    const MagickRealType c4 = 0.299175768961095380104447394070231517712e-7L;
-    const MagickRealType c5 = -0.582555275175235235925786868156315453570e-9L;
-    const MagickRealType c6 = 0.774885118857072154223233850399192557934e-11L;
-    const MagickRealType c7 = -0.686148809066333092764596425714057372964e-13L;
-    const MagickRealType c8 = 0.371085247462909594457662716426170281684e-15L;
-    const MagickRealType c9 = -0.944551950759515118228796037513456335763e-18L;
-    const MagickRealType p =
-      c0+xx*(c1+xx*(c2+xx*(c3+xx*(c4+xx*(c5+xx*(c6+xx*(c7+xx*(c8+xx*c9))))))));
-    const MagickRealType d0 = 1.0L;
-    const MagickRealType d1 = 0.463782211680615975951490586564903936283e-1L;
-    const MagickRealType d2 = 0.984899056548092584226994406603163505777e-3L;
-    const MagickRealType d3 = 0.121314604267142674069019025409802158375e-4L;
-    const MagickRealType d4 = 0.881998514405598677970025517260813044225e-7L;
-    const MagickRealType d5 = 0.310377434094436341006055666680844291856e-9L;
-    const MagickRealType q = d0+xx*(d1+xx*(d2+xx*(d3+xx*(d4+xx*d5))));
-    return((xx-1.0)*(xx-4.0)*(xx-9.0)*(xx-16.0)/q*p);
 #endif
   }
 }