[jira] [Comment Edited] (GEOMETRY-46) Additional UnitVector methods

["Gilles Sadowski (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GEOMETRY-46?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16938138#comment-16938138 ] 

Gilles Sadowski edited comment on GEOMETRY-46 at 9/25/19 11:47 PM:
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{quote}breaks ValJO specification
{quote}
How?
{quote}off [...] if Vector2D and Vector3D did things one way and Vector1D did it another.
{quote}
Of course, the same changes would be applied to those other classes as well.
{quote}What benefits does this design bring?
{quote}

# Robustness: Factory method "from" ensures normalization happens in the class that claims to produce normalized vectors (removes the need for a comment such as "Callers are responsible for ensuring that the given values represent a normalized vector"). Also, preconditions are checked within that same class.
 # Explicit representation of a useful concept (cf. basis vectors). Could make some codes slightly leaner (one never needs to call "normalize" on a {{Unit}} instance). For example, method "directionTo(v)" should be declared to return a "Unit" vector. Ditto for method "normalize", of course. ;)
 # Static method "normalize(double x)" (and equivalent in 2D and 3D) can be removed; and this is good IMO for several reasons:
 ** Mix between vector transformation and factory method (double -> vector).
 ** Unnecessary addition to the API.
 ** Asymmetric usage ("of" vs "normalize") in higher level API ("AffineTransformMatrix1D").


was (Author: erans):
{quote}breaks ValJO specification
{quote}
How?
{quote}off [...] if Vector2D and Vector3D did things one way and Vector1D did it another.
{quote}
Of course, the same changes would be applied to those other classes as well.
{quote}What benefits does this design bring?
{quote} # Robustness: Factory method "from" ensures normalization happens in the class that claims to produce normalized vectors (removes the need for a comment such as "Callers are responsible for ensuring that the given values represent a normalized vector"). Also, preconditions are checked within that same class.
 # Explicit representation of a useful concept (cf. basis vectors). Could make some codes slightly leaner (one never needs to call "normalize" on a {{Unit}} instance). For example, method "directionTo(v)" should be declared to return a "Unit" vector. Ditto for method "normalize", of course. ;)
 # Static method "normalize(double x)" (and equivalent in 2D and 3D) can be removed; and this is good IMO for several reasons:
 ** Mix between vector transformation and factory method (double -> vector).
 ** Unnecessary addition to the API.
 ** Asymmetric usage ("of" vs "normalize") in higher level API ("AffineTransformMatrix1D").

> Additional UnitVector methods
> -----------------------------
>
>                 Key: GEOMETRY-46
>                 URL: https://issues.apache.org/jira/browse/GEOMETRY-46
>             Project: Apache Commons Geometry
>          Issue Type: Improvement
>            Reporter: Matt Juntunen
>            Priority: Minor
>              Labels: easyfix, pull-request-available, starter
>         Attachments: GEOMETRY-46.patch
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> The following methods should be overridden in the {{UnitVector}} private subclasses of the {{Vector?D}} classes:
> * {{normSq}} -- should return {{1}} for consistency with {{norm}}
> * {{negate}} -- should be overridden to also return a {{UnitVector}} instance instead of a regular {{Vector?D}} 



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