SimpleMatrix - Revision history

Peter: /* Working with DMatrixRMaj */

2017-05-18T04:56:26Z

Working with DMatrixRMaj

Peter at 04:55, 18 May 2017

2017-05-18T04:55:14Z

Peter at 15:02, 26 March 2015

2015-03-26T15:02:40Z

Peter at 15:02, 26 March 2015

2015-03-26T15:02:04Z

Peter: Created page with " SimpleMatrix is an interface that provides an easy to use object oriented way of doing linear algebra. It is a wrapper around the procedural interface in EJML and was origin..."

2015-03-26T06:31:59Z

Created page with " SimpleMatrix is an interface that provides an easy to use object oriented way of doing linear algebra. It is a wrapper around the procedural interface in EJML and was origin..."

New page

SimpleMatrix is an interface that provides an easy to use object oriented way of doing linear algebra. It is a wrapper around the procedural interface in EJML and was originally inspired by [http://math.nist.gov/javanumerics/jama/ Jama]. When using SimpleMatrix, memory management is automatically handled and it allows commands to be chained together using a flow paradigm. Switching between SimpleMatrix and the [[Procedural]] interface is easy, enabling the two programming paradigms to be mixed in the same code base.

When invoking a function in SimpleMatrix none of the input matrices, including the 'this' matrix, are modified during the function call. There is a slight performance hit when using SimpleMatrix and less control over memory management. See [[Performance]] for a comparison of runtime performance of the different interfaces.

Below is a brief overview of SimpleMatrix concepts.

== Chaining Operations ==

When using SimpleMatrix operations can be chained together. Chained operations are often easier to read and write.
<syntaxhighlight lang="java">
public SimpleMatrix process( SimpleMatrix A , SimpleMatrix B ) {
return A.transpose().mult(B).scale(12).invert();
}
</syntaxhighlight>
is equivalent to the following Matlab code:
<syntaxhighlight lang="java">C = inv((A' * B)*12.0)</syntaxhighlight>

== Working with DenseMatrix64F ==

To convert a [DenseMatrix64F DenseMatrix64F] into a SimpleMatrix call the wrap() function. Then to get access to the internal DenseMatrix64F inside of a SimpleMatrix call getMatrix().
<syntaxhighlight lang="java">
public DenseMatrix64F compute( DenseMatrix64F A , DenseMatrix64F B ) {
SimpleMatrix A_ = SimpleMatrix.wrap(A);
SimpleMatrix B_ = SimpleMatrix.wrap(B);

return A_.mult(B_).getMatrix();
}
</syntaxhighlight>

A DenseMatrix64F can also be passed into the SimpleMatrix constructor, but this will copy the input matrix. Unlike with when wrap is used, changed to the new SimpleMatrix will not modify the original DenseMatrix64F.

== Accessors ==
*get( row , col )
*set( row , col , value )
** Returns or sets the value of an element at the specified row and column.
*get( index )
*set( index )
** Returns or sets the value of an element at the specified index. Useful for vectors and element-wise operations.
*iterator( boolean rowMajor, int minRow, int minCol, int maxRow, int maxCol )
** An iterator that iterates through the sub-matrix by row or by column.

== Submatrices ==

A submatrix is a matrix whose elements are a subset of another matrix. Several different functions are provided for manipulating submatrices.

; extractMatrix : Extracts a rectangular submatrix from the original matrix.
; extractDiag : Creates a column vector containing just the diagonal elements of the matrix.
; extractVector : Extracts either an entire row or column.
; insertIntoThis : Inserts the passed in matrix into 'this' matrix.
; combine : Creates a now matrix that is a combination of the two inputs.

== Decompositions ==

Simplified ways to use popular matrix decompositions is provided. These decompositions provide fewer choices than the equivalent for DenseMatrix64F, but should meet most people needs.

; svd : Computes the singular value decomposition of 'this' matrix
; eig : Computes the eigen value decomposition of 'this' matrix

Direct access to other decompositions (e.g. QR and Cholesky) is not provided in SimpleMatrix because solve() and inv() is provided instead. In more advanced applications use the operator interface instead to compute those decompositions.

== Solve and Invert ==

; solve : Computes the solution to the set of linear equations
; inv : Computes the inverse of a square matrix
; pinv : Computes the pseudo-inverse for an arbitrary matrix

See [[Solving Linear Systems]] for more details on solving systems of equations.

== Other Functions ==

SimpleMatrix provides many other functions. For a complete list see the JavaDoc for [http://ejml.org/javadoc/org/ejml/simple/SimpleBase.html SimpleBase] and [http://ejml.org/javadoc/org/ejml/simple/SimpleMatrix.html SimpleMatrix]. Note that SimpleMatrix extends SimpleBase.

@@ Line 19: / Line 19: @@
 == Working with DMatrixRMaj ==
-To convert a [[DMatrixRMaj DMatrixRMaj]] into a SimpleMatrix call the wrap() function.  Then to get access to the internal DMatrixRMaj inside of a SimpleMatrix call getMatrix().
+To convert a {{DataDocLink|DMatrixRMaj}} into a SimpleMatrix call the wrap() function.  Then to get access to the internal DMatrixRMaj inside of a SimpleMatrix call getMatrix().
 <syntaxhighlight lang="java">
 public DMatrixRMaj compute( DMatrixRMaj A , DMatrixRMaj B ) {

@@ Line 70: / Line 70: @@
 == Other Functions ==
-SimpleMatrix provides many other functions.  For a complete list see the JavaDoc for {{DocLink|org/ejml/simple/SimpleBase.html|SimpleBase}} and {{DocLink|org/ejml/simple/SimpleMatrix.html|SimpleMatrix}.  Note that SimpleMatrix extends SimpleBase.
+SimpleMatrix provides many other functions.  For a complete list see the JavaDoc for {{DocLink|org/ejml/simple/SimpleBase.html|SimpleBase}} and {{DocLink|org/ejml/simple/SimpleMatrix.html|SimpleMatrix}}.  Note that SimpleMatrix extends SimpleBase.
 == Adding Functionality ==
 You can turn SimpleMatrix into your own data structure and extend its capabilities. See the [[Example_Customizing_SimpleMatrix|example on customizing SimpleMatrix]] for the details.

@@ Line 17: / Line 17: @@
-== Working with DenseMatrix64F ==
+== Working with DMatrixRMaj ==
-To convert a [DenseMatrix64F DenseMatrix64F] into a SimpleMatrix call the wrap() function.  Then to get access to the internal DenseMatrix64F inside of a SimpleMatrix call getMatrix().
+To convert a [[DMatrixRMaj DMatrixRMaj]] into a SimpleMatrix call the wrap() function.  Then to get access to the internal DMatrixRMaj inside of a SimpleMatrix call getMatrix().
 <syntaxhighlight lang="java">
-public DenseMatrix64F compute( DenseMatrix64F A , DenseMatrix64F B ) {
+public DMatrixRMaj compute( DMatrixRMaj A , DMatrixRMaj B ) {
      SimpleMatrix A_ = SimpleMatrix.wrap(A);
      SimpleMatrix B_ = SimpleMatrix.wrap(B);
-     return A_.mult(B_).getMatrix();
+     return (DMatrixRMaj)A_.mult(B_).getMatrix();
+}
 </syntaxhighlight>
-A {{DataDocLink|DenseMatrix64F}} can also be passed into the SimpleMatrix constructor, but this will copy the input matrix.  Unlike with when wrap is used, changed to the new SimpleMatrix will not modify the original DenseMatrix64F.
+A {{DataDocLink|DMatrixRMaj}} can also be passed into the SimpleMatrix constructor, but this will copy the input matrix.  Unlike with when wrap is used, changed to the new SimpleMatrix will not modify the original DMatrixRMaj.
 == Accessors ==
@@ Line 53: / Line 53: @@
 == Decompositions ==
-Simplified ways to use popular matrix decompositions is provided.  These decompositions provide fewer choices than the equivalent for DenseMatrix64F, but should meet most people needs.
+Simplified ways to use popular matrix decompositions is provided.  These decompositions provide fewer choices than the equivalent for DMatrixRMaj, but should meet most people needs.
 ; svd : Computes the singular value decomposition of 'this' matrix

@@ Line 1: / Line 1: @@
 SimpleMatrix is an interface that provides an easy to use object oriented way of doing linear algebra.  It is a wrapper around the procedural interface in EJML and was originally inspired by [http://math.nist.gov/javanumerics/jama/ Jama].  When using SimpleMatrix, memory management is automatically handled and it allows commands to be chained together using a flow paradigm.  Switching between SimpleMatrix and the [[Procedural]] interface is easy, enabling the two programming paradigms to be mixed in the same code base.
@@ Line 30: / Line 29: @@
 </syntaxhighlight>
-A DenseMatrix64F can also be passed into the SimpleMatrix constructor, but this will copy the input matrix.  Unlike with when wrap is used, changed to the new SimpleMatrix will not modify the original DenseMatrix64F.
+A {{DataDocLink|DenseMatrix64F}} can also be passed into the SimpleMatrix constructor, but this will copy the input matrix.  Unlike with when wrap is used, changed to the new SimpleMatrix will not modify the original DenseMatrix64F.
 == Accessors ==
@@ Line 71: / Line 70: @@
 == Other Functions ==
-SimpleMatrix provides many other functions.  For a complete list see the JavaDoc for [http://ejml.org/javadoc/org/ejml/simple/SimpleBase.html SimpleBase] and [http://ejml.org/javadoc/org/ejml/simple/SimpleMatrix.html SimpleMatrix].  Note that SimpleMatrix extends SimpleBase.
+SimpleMatrix provides many other functions.  For a complete list see the JavaDoc for {{DocLink|org/ejml/simple/SimpleBase.html|SimpleBase}} and {{DocLink|org/ejml/simple/SimpleMatrix.html|SimpleMatrix}.  Note that SimpleMatrix extends SimpleBase.