[
https://issues.apache.org/jira/browse/MATH-181?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12564531#action_12564531
]
luc edited comment on MATH-181 at 1/31/08 2:39 PM:
-------------------------------------------------------------
I have checked the ideas I had about denominator. They do not address your
issue, so the patch as applied is good.
However, I noticed the last statement in the private constructor was a call to
reduce. This seems strange to me because a known property of the recursive
algorithm to build the convergents cn=pn/qn is that they are already reduced.
This is a result of applying the Bezout theorem to the easily proved recursive
property p(n)q(n-1) - p(n-1)q(n) = (-1)^(n+1). This property holds even if a1
is completely wrong due to numerical errors.
When I remove this statement, the existing test succeed as expected. I did not
find any related information in the log message nor in JIRA.
May I remove this statement or did I miss something ?
was (Author: luc):
I have checked the ideas I had about denominator. They are do not address
your issue, so the patch as applied is good.
However, I noticed the last statement in the private constructor was a call to
reduce. This seems strange to me because a known property of the recursive
algorithm to build the convergents cn=pn/qn is that they are already reduced.
This is a result of applying the Bezout theorem to the easily proved recursive
property p(n)q(n-1) - p(n-1)q(n) = (-1)^(n+1). This property holds even if a1
is completely wrong due to numerical errors.
When I remove this statement, the existing test succeed as expected. I did not
find any related information in the log message nor in JIRA.
May I remove this statement or did I miss something ?
> Specify the maximum of digits when parsing a Fraction
> -----------------------------------------------------
>
> Key: MATH-181
> URL: https://issues.apache.org/jira/browse/MATH-181
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 1.1
> Reporter: Niall Pemberton
> Priority: Minor
> Attachments: MATH-181-FractionDigitsLimit-v2.patch,
> MATH-181-FractionDigitsLimit.patch, MATH-181-FractionMaxDenominator.patch
>
>
> Firstly, thanks for the Fraction code - I've adapated it for something I'm
> working on and I didn't have a clue how to convert a decimal to a fraction :)
> Excel spreadsheets have the facility to specify a fraction format where you
> specify the maximum number of denominator digits to display.
> So for example:
> format "?/?" displays decimal values formatted in the range 1/2 to n/9
> format "??/??" displays decimal values formatted in the range 1/2 to n/99
> format "???/???" displays decimal values formatted in the range 1/2 to
> n/999 etc
> In excel then the value 0.6152 displays as 3/5, 8/13 and 510/829 respectively
> for the above 3 formats.
> I'm attaching a patch for the Fraction class which adds a new constructor
> where the maximum number of digits can be specified, rather than the epsilon
> value.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
