[Maxima-commits] CVS: maxima/tests rtest_expintegral.mac, 1.7, 1.8 rtest_gamma.mac, 1.39, 1.40

[Raymond T. <rt...@us...>]

Update of /cvsroot/maxima/maxima/tests
In directory sfp-cvsdas-1.v30.ch3.sourceforge.com:/tmp/cvs-serv30905/tests

Modified Files:
	rtest_expintegral.mac rtest_gamma.mac 
Log Message:
Bug 2909980: optimization for log of bfloats

Optimize computation of log of bfloats by using the fact that each
bfloat is frac*2^exp, where 1/2 < frac <= 1.

src/float.lisp:
o Add new variable bigfloat_log2 to hold the current bigfloat value of
  log(2b0).
o Add function fplog2 to return log(2b0) of the correct precision.
o Modify big-float-log to compute logs using the formula
  log(frac*2^exp) = log(frac) + exp*log(2).

tests/rtest_expintegral.mac:
o Test 73 (expintegral_e(1,.25b0)) no longer is accurate to 64 digits;
  reduce accuracy to 63.

tests/rtest_gamma.mac:
o Test 636 (beta_incomplete(1b0,1,z)) is no longer exactly
  1b0*z. Change test to allow a small error.



Index: rtest_expintegral.mac
===================================================================
RCS file: /cvsroot/maxima/maxima/tests/rtest_expintegral.mac,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -d -r1.7 -r1.8
--- rtest_expintegral.mac	1 Aug 2009 13:07:02 -0000	1.7
+++ rtest_expintegral.mac	14 Dec 2009 04:55:50 -0000	1.8
@@ -261,7 +261,7 @@
 test_value(
   expintegral_e(1,0.25b0),
   1.044282634443738194536438161232282251891528374744802718635140468b0,
-  64);
+  63);
 true;
 
 test_value(

Index: rtest_gamma.mac
===================================================================
RCS file: /cvsroot/maxima/maxima/tests/rtest_gamma.mac,v
retrieving revision 1.39
retrieving revision 1.40
diff -u -d -r1.39 -r1.40
--- rtest_gamma.mac	29 Oct 2009 17:49:06 -0000	1.39
+++ rtest_gamma.mac	14 Dec 2009 04:55:50 -0000	1.40
@@ -3165,8 +3165,9 @@
 
 beta_incomplete(1.0,1,z);
 1.0*z;
-beta_incomplete(1.0b0,1,z);
-1.0b0*z;
+/* Unfortunate, but we don't get exactly 1.0b0 */
+(closeto(beta_incomplete(1.0b0,1,z)/z,1b0,1b-15));
+true;
 beta_incomplete(1.0,1,1/2);
 0.5;
 beta_incomplete(1.0b0,1,1/2);