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Fix misleading output from `(help rationalize)'

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* numbers.c (scm_rationalize): Update docstring to match the
	manual (which is more correct).  Change argument "err" to "eps",
	also to match the manual.
This commit is contained in:
Neil Jerram 2008-08-03 00:18:33 +01:00
parent e460586430
commit 7ed52b7bbb
3 changed files with 22 additions and 5 deletions
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1
NEWS
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@ -28,6 +28,7 @@ application code.
** Fix build issue on Tru64 and ia64-hp-hpux11.23 (`SCM_UNPACK' macro) ** Fix build issue on Tru64 and ia64-hp-hpux11.23 (`SCM_UNPACK' macro)
** Fix build issue on mips, mipsel, powerpc and ia64 (stack direction) ** Fix build issue on mips, mipsel, powerpc and ia64 (stack direction)
** Fix build issue on hppa2.0w-hp-hpux11.11 (`dirent64' and `readdir64_r') ** Fix build issue on hppa2.0w-hp-hpux11.11 (`dirent64' and `readdir64_r')
** Fix misleading output from `(help rationalize)'
Changes in 1.8.5 (since 1.8.4) Changes in 1.8.5 (since 1.8.4)

6
libguile/ChangeLog
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@ -1,3 +1,9 @@
2008-08-02 Neil Jerram <neil@ossau.uklinux.net>
* numbers.c (scm_rationalize): Update docstring to match the
manual (which is more correct). Change argument "err" to "eps",
also to match the manual.
2008-07-17 Neil Jerram <neil@ossau.uklinux.net> 2008-07-17 Neil Jerram <neil@ossau.uklinux.net>
From Thiemo Seufer <ths@networkno.de>: From Thiemo Seufer <ths@networkno.de>:

20
libguile/numbers.c
View file

@ -5599,8 +5599,18 @@ SCM_DEFINE (scm_inexact_to_exact, "inexact->exact", 1, 0, 0,
#undef FUNC_NAME #undef FUNC_NAME
SCM_DEFINE (scm_rationalize, "rationalize", 2, 0, 0, SCM_DEFINE (scm_rationalize, "rationalize", 2, 0, 0,
(SCM x, SCM err), (SCM x, SCM eps),
"Return an exact number that is within @var{err} of @var{x}.") "Returns the @emph{simplest} rational number differing\n"
"from @var{x} by no more than @var{eps}.\n"
"\n"
"As required by @acronym{R5RS}, @code{rationalize} only returns an\n"
"exact result when both its arguments are exact. Thus, you might need\n"
"to use @code{inexact->exact} on the arguments.\n"
"\n"
"@lisp\n"
"(rationalize (inexact->exact 1.2) 1/100)\n"
"@result{} 6/5\n"
"@end lisp")
#define FUNC_NAME s_scm_rationalize #define FUNC_NAME s_scm_rationalize
{ {
if (SCM_I_INUMP (x)) if (SCM_I_INUMP (x))
@ -5632,7 +5642,7 @@ SCM_DEFINE (scm_rationalize, "rationalize", 2, 0, 0,
converges after less than a dozen iterations. converges after less than a dozen iterations.
*/ */
err = scm_abs (err); eps = scm_abs (eps);
while (++i < 1000000) while (++i < 1000000)
{ {
a = scm_sum (scm_product (a1, tt), a2); /* a = a1*tt + a2 */ a = scm_sum (scm_product (a1, tt), a2); /* a = a1*tt + a2 */
@ -5640,11 +5650,11 @@ SCM_DEFINE (scm_rationalize, "rationalize", 2, 0, 0,
if (scm_is_false (scm_zero_p (b)) && /* b != 0 */ if (scm_is_false (scm_zero_p (b)) && /* b != 0 */
scm_is_false scm_is_false
(scm_gr_p (scm_abs (scm_difference (ex, scm_divide (a, b))), (scm_gr_p (scm_abs (scm_difference (ex, scm_divide (a, b))),
err))) /* abs(x-a/b) <= err */ eps))) /* abs(x-a/b) <= eps */
{ {
SCM res = scm_sum (int_part, scm_divide (a, b)); SCM res = scm_sum (int_part, scm_divide (a, b));
if (scm_is_false (scm_exact_p (x)) if (scm_is_false (scm_exact_p (x))
|| scm_is_false (scm_exact_p (err))) || scm_is_false (scm_exact_p (eps)))
return scm_exact_to_inexact (res); return scm_exact_to_inexact (res);
else else
return res; return res;