Hi Gilles,
2012/8/31 Gilles Sadowski <gil...@harfang.homelinux.org>:
> Hello Sébastien.
>
>> Author: celestin
>> Date: Fri Aug 31 03:12:16 2012
>> New Revision: 1379270
>>
>> URL: http://svn.apache.org/viewvc?rev=1379270&view=rev
>> Log:
>> MATH-849: changed boundary case x = 8.0 in double Gamma.logGamma(double).
>>
>> Modified:
>>
>> commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
>>
>> Modified:
>> commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
>> URL:
>> http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java?rev=1379270&r1=1379269&r2=1379270&view=diff
>> ==============================================================================
>> ---
>> commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
>> (original)
>> +++
>> commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
>> Fri Aug 31 03:12:16 2012
>> @@ -222,9 +222,9 @@ public class Gamma {
>> * Returns the value of log Γ(x) for x > 0.
>> * </p>
>> * <p>
>> - * For x < 8, the implementation is based on the double precision
>> + * For x ≤ 8, the implementation is based on the double precision
>
> My personal taste would be to write this as
> ---
> {@code x <= 8}
> ---
> [As I'm not an HTML parser,
>
I'm a bit disappointed by your poor parsing capabilities ;-)
> it always takes me a few moments to figure out a
> sequence such as "x < 8", while it is easier to focus on the central part
> of "{@code x <= 8}".]
>
> So, if nobody disagrees, this could become a formatting rule. [The rationale
> (to be included in the document you proposed to create) would be that
> Javadoc comments should be as easy as possible to read in their source form,
> for the developer's sake.]
>
Yeah, and it gets worse when I had to find a work around for the
decimal point not being interpreted as the end of the first sentence:
I ended up with something like
Returns the value of 1 / Γ(1 + x) - 1 for -0.5 ≤ x ≤
1.5. In case you wondered, . is simply '.'. This is uggly, I
agree.
I was thinking this very morning of something like "HTML tags are
allowed as long as reading the source file is still reasonably easy".
I'm quite happy with a more radical approach, like "HTML text
formatting tags should be avoided as much as possible. Paragraph
formatting (<p>, <li>, <pre>, ... is allowed)". Note that it has not
been applied consistently in CM yet : in some parts, formulae are
formatted with HTML tags, in other parts, it's pure {@code }. I
contributed to this mess :-(
As sebb mentions {@code } prevents *any* formatting, but this would
not really be an issue. If needed, we can use <pre></pre> tags and
nice text-based equations (again, tools like Maxima can help a lot),
even if it looks old fashioned.
I'll write something up in the JIRA ticket, so that everyone can review it.
Thanks for this suggestion,
Sébastien
>
> Best regards,
> Gilles
>
>> * implementation in the <em>NSWC Library of Mathematics
>> Subroutines</em>,
>> - * {@code DGAMLN}. For x ≥ 8, the implementation is based on
>> + * {@code DGAMLN}. For x > 8, the implementation is based on
>> * </p>
>> * <ul>
>> * <li><a href="http://mathworld.wolfram.com/GammaFunction.html";>Gamma
>> @@ -249,7 +249,7 @@ public class Gamma {
>> return logGamma1p(x) - FastMath.log(x);
>> } else if (x <= 2.5) {
>> return logGamma1p((x - 0.5) - 0.5);
>> - } else if (x < 8.0) {
>> + } else if (x <= 8.0) {
>> final int n = (int) FastMath.floor(x - 1.5);
>> double prod = 1.0;
>> for (int i = 1; i <= n; i++) {
>>
>>
>
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