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From Sébastien Brisard (Updated) (JIRA) <j...@apache.org>
Subject [jira] [Updated] (MATH-765) Refactoring the vector and matrix classes
Date Thu, 08 Mar 2012 06:48:59 GMT

     [ https://issues.apache.org/jira/browse/MATH-765?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Sébastien Brisard updated MATH-765:
-----------------------------------

    Description: 
{panel:title=Warning|borderStyle=solid}
This is not a bug report, but rather a summary of all discussions which have taken place on
the mailing list regarding the refactoring of the vector and matrix classes. Indeed, it has
been argued many times that the {{RealVector}} and {{RealMatrix}} interfaces are really cluttered,
and could benefit from other approaches (like functional programming). 

The description of this ticket will be updated as the discussion progresses on the mailing-list,
and new JIRA tickets will be created to carry out the "real" work. {color:red}In order to
keep this ticket tidy, contributors should refrain from commenting on this website. Instead,
messages should be posted on the dev mailing-list{color}.
{panel}


h1. The current API (version 3.0)

In this section, the current interfaces for vectors and matrices are compared. Vectors and
matrices are two mathematical objects which are very close in nature. Their implementations
should therefore be as similar as possible. The methods will be sorted as follows
* methods reflecting the mathematical structure of vector space: addition, multiplication
by a scalar, matrix-vector product, ...
* methods reflecting the mathematical structure of euclidean space
* ...

h2. Methods reflecting the mathematical structure of vector space
h3. List of the methods
|| {{RealVector}}                      || {{RealMatrix}}                                 
         || Comments ||
| {{RealVector add(RealVector v)}}     | {{RealMatrix add(RealMatrix m)}}                
         |           |
| {{int getDimension()}}               | {{int getRowDimension()}},\\ {{int getColumnDimension()}}
|           |
| {{RealVector mapMultiply(double d)}} | {{scalarMultiply(double d)}}                    
         | (1)       |
|                                      | {{double getTrace()}}                           
         |           |
|                                      | {{multiply(RealMatrix m)}}                      
         |           |
|                                      | {{double[] operate(double[])}}                  
         | (2)       |
|                                      | {{RealVector operate(RealVector)}}              
         |           |
|                                      | {{RealMatrix power(int p)}}                     
         |           |
|                                      | {{double[] preMultiply(double[])}}              
         | (2)       |
|                                      | {{RealMatrix preMultiply(RealMatrix)}}          
         |           |
|                                      | {{RealVector preMultiply(RealVector)}}          
         |           |
|                                      | {{RealMatrix transpose()}}                      
         |           |

h3. Comments on the above methods
h4. Comment (1)
{{RealVector RealVector.mapMultiply(double)}} and {{RealMatrix RealMatrix.scalarMultiply(double)}}
perform essentially the same task. Readibility of the classes would be improved if they add
the same name. This is very important since these methods reflect the fact that the space
of vectors as well as the space of matrices are two vector spaces.

h4. Comment (2)
Prior to the release of version 3.0, all methods involving taking as argument, or returning,
{{double[]}} representing vectors were removed. The rationale for this is that calling {{new
ArrayRealVector(double[], false)}} is very easy, and comes at virtually no cost (see MATH-653
and MATH-660). It might be worth considering the same simplification for the {{RealMatrix}}
interface.

h2. Methods reflecting the mathematical structure of euclidean space

h2. Constructors, factory methods and related methods

h2. Manipulation of entries

h2. Various norms

h2. Functional-programming-like methods

  was:
{panel:title=Warning|borderStyle=solid}
This is not a bug report, but rather a summary of all discussions which have taken place on
the mailing list regarding the refactoring of the vector and matrix classes. Indeed, it has
been argued many times that the {{RealVector}} and {{RealMatrix}} interfaces are really cluttered,
and could benefit from other approaches (like functional programming). 

The description of this ticket will be updated as the discussion progresses on the mailing-list,
and new JIRA tickets will be created to carry out the "real" work. In order to keep this ticket
tidy, contributors should refrain from commenting on this website. Instead, messages should
be posted on the dev mailing-list.
{panel}


h1. The current API (version 3.0)

In this section, the current interfaces for vectors and matrices are compared. Vectors and
matrices are two mathematical objects which are very close in nature. Their implementations
should therefore be as similar as possible. The methods will be sorted as follows
* methods reflecting the mathematical structure of vector space: addition, multiplication
by a scalar, matrix-vector product, ...
* methods reflecting the mathematical structure of euclidean space
* ...

h2. Methods reflecting the mathematical structure of vector space
|| {{RealVector}}                      || {{RealMatrix}}                                 
         || Comments ||
| {{RealVector add(RealVector v)}}     | {{RealMatrix add(RealMatrix m)}}                
         |           |
| {{int getDimension()}}               | {{int getRowDimension()}},\\ {{int getColumnDimension()}}
|           |
| {{RealVector mapMultiply(double d)}} | {{scalarMultiply(double d)}}                    
         |           |
|                                      | {{multiply(RealMatrix m)}}                      
         |           |
|                                      | {{double[] operate(double[])}}                  
         |           |
|                                      | {{RealVector operate(RealVector)}}              
         |           |
|                                      | {{double[] preMultiply(double[])}}              
         |           |
|                                      | {{RealMatrix preMultiply(RealMatrix)}}          
         |           |
|                                      | {{RealVector preMultiply(RealVector)}}          
         |           |

h2. Methods reflecting the mathematical structure of euclidean space

    
> Refactoring the vector and matrix classes
> -----------------------------------------
>
>                 Key: MATH-765
>                 URL: https://issues.apache.org/jira/browse/MATH-765
>             Project: Commons Math
>          Issue Type: Improvement
>    Affects Versions: 4.0
>            Reporter: Sébastien Brisard
>              Labels: api-change, linear
>
> {panel:title=Warning|borderStyle=solid}
> This is not a bug report, but rather a summary of all discussions which have taken place
on the mailing list regarding the refactoring of the vector and matrix classes. Indeed, it
has been argued many times that the {{RealVector}} and {{RealMatrix}} interfaces are really
cluttered, and could benefit from other approaches (like functional programming). 
> The description of this ticket will be updated as the discussion progresses on the mailing-list,
and new JIRA tickets will be created to carry out the "real" work. {color:red}In order to
keep this ticket tidy, contributors should refrain from commenting on this website. Instead,
messages should be posted on the dev mailing-list{color}.
> {panel}
> h1. The current API (version 3.0)
> In this section, the current interfaces for vectors and matrices are compared. Vectors
and matrices are two mathematical objects which are very close in nature. Their implementations
should therefore be as similar as possible. The methods will be sorted as follows
> * methods reflecting the mathematical structure of vector space: addition, multiplication
by a scalar, matrix-vector product, ...
> * methods reflecting the mathematical structure of euclidean space
> * ...
> h2. Methods reflecting the mathematical structure of vector space
> h3. List of the methods
> || {{RealVector}}                      || {{RealMatrix}}                            
              || Comments ||
> | {{RealVector add(RealVector v)}}     | {{RealMatrix add(RealMatrix m)}}           
              |           |
> | {{int getDimension()}}               | {{int getRowDimension()}},\\ {{int getColumnDimension()}}
|           |
> | {{RealVector mapMultiply(double d)}} | {{scalarMultiply(double d)}}               
              | (1)       |
> |                                      | {{double getTrace()}}                      
              |           |
> |                                      | {{multiply(RealMatrix m)}}                 
              |           |
> |                                      | {{double[] operate(double[])}}             
              | (2)       |
> |                                      | {{RealVector operate(RealVector)}}         
              |           |
> |                                      | {{RealMatrix power(int p)}}                
              |           |
> |                                      | {{double[] preMultiply(double[])}}         
              | (2)       |
> |                                      | {{RealMatrix preMultiply(RealMatrix)}}     
              |           |
> |                                      | {{RealVector preMultiply(RealVector)}}     
              |           |
> |                                      | {{RealMatrix transpose()}}                 
              |           |
> h3. Comments on the above methods
> h4. Comment (1)
> {{RealVector RealVector.mapMultiply(double)}} and {{RealMatrix RealMatrix.scalarMultiply(double)}}
perform essentially the same task. Readibility of the classes would be improved if they add
the same name. This is very important since these methods reflect the fact that the space
of vectors as well as the space of matrices are two vector spaces.
> h4. Comment (2)
> Prior to the release of version 3.0, all methods involving taking as argument, or returning,
{{double[]}} representing vectors were removed. The rationale for this is that calling {{new
ArrayRealVector(double[], false)}} is very easy, and comes at virtually no cost (see MATH-653
and MATH-660). It might be worth considering the same simplification for the {{RealMatrix}}
interface.
> h2. Methods reflecting the mathematical structure of euclidean space
> h2. Constructors, factory methods and related methods
> h2. Manipulation of entries
> h2. Various norms
> h2. Functional-programming-like methods

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