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Posted to dev@commons.apache.org by Luc Maisonobe <Lu...@free.fr> on 2010/10/03 20:21:53 UTC
[math] comments on MATH-391
Hi all,
I have fixed MATH-391. Now vectors can be built with 0 length using
several constructors.
There is however one remaining problem, for Field-based vectors (i.e.
ArrayFieldVector). For these vectors, we need to store the field in
addition to the vector components. For example a Fraction Vectors also
stores a reference to FractionField. When a vector is built from a non
empty array, the field can be retrieved from the first element, using
d[0].getField(). Since 0 length vectors are now allowed, I add to create
additional constructors that pass the field as an additional constructor
parameter. This is much cleaner than the previous choice.
Since the field is mainly a compile-time constant for a given program
(people now when they use Fraction or Complex or Dfp), I would like to
deprecate the former constructors in 2.2 and remove them in 3.0. This
means someone building a Fraction vector would use:
Fraction[] data = ...;
ArrayFieldVector<Fraction> vector =
new ArrayFieldVector<Fraction>(FractionField.getInstance(),
data, false);
instead of:
Fraction[] data = ...;
ArrayFieldVector<Fraction> vector =
new ArrayFieldVector<Fraction>(data, false);
which don't work for zero-length.
What do you think about this proposed deprecation ?
Luc
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Re: [math] comments on MATH-391
Posted by Phil Steitz <ph...@gmail.com>.
On 10/3/10 2:21 PM, Luc Maisonobe wrote:
> Hi all,
>
> I have fixed MATH-391. Now vectors can be built with 0 length using
> several constructors.
>
> There is however one remaining problem, for Field-based vectors (i.e.
> ArrayFieldVector). For these vectors, we need to store the field in
> addition to the vector components. For example a Fraction Vectors also
> stores a reference to FractionField. When a vector is built from a non
> empty array, the field can be retrieved from the first element, using
> d[0].getField(). Since 0 length vectors are now allowed, I add to create
> additional constructors that pass the field as an additional constructor
> parameter. This is much cleaner than the previous choice.
>
> Since the field is mainly a compile-time constant for a given program
> (people now when they use Fraction or Complex or Dfp), I would like to
> deprecate the former constructors in 2.2 and remove them in 3.0. This
> means someone building a Fraction vector would use:
>
> Fraction[] data = ...;
> ArrayFieldVector<Fraction> vector =
> new ArrayFieldVector<Fraction>(FractionField.getInstance(),
> data, false);
>
> instead of:
>
> Fraction[] data = ...;
> ArrayFieldVector<Fraction> vector =
> new ArrayFieldVector<Fraction>(data, false);
>
> which don't work for zero-length.
>
> What do you think about this proposed deprecation ?
+1 - nice solution
Phil
>
> Luc
>
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