org.scijava.vecmath

## Class GMatrix

• All Implemented Interfaces:
Serializable, Cloneable

```public class GMatrix
extends Object
implements Serializable, Cloneable```
A double precision, general, dynamically-resizable, two-dimensional matrix class. Row and column numbering begins with zero. The representation is row major.
Serialized Form
• ### Constructor Summary

Constructors
Constructor and Description
`GMatrix(GMatrix matrix)`
Constructs a new GMatrix and copies the initial values from the parameter matrix.
```GMatrix(int nRow, int nCol)```
Constructs an nRow by NCol identity matrix.
```GMatrix(int nRow, int nCol, double[] matrix)```
Constructs an nRow by nCol matrix initialized to the values in the matrix array.
• ### Method Summary

All Methods
Modifier and Type Method and Description
`void` `add(GMatrix m1)`
Sets the value of this matrix to sum of itself and matrix m1.
`void` ```add(GMatrix m1, GMatrix m2)```
Sets the value of this matrix to the matrix sum of matrices m1 and m2.
`Object` `clone()`
Creates a new object of the same class as this object.
`void` ```copySubMatrix(int rowSource, int colSource, int numRow, int numCol, int rowDest, int colDest, GMatrix target)```
Copies a sub-matrix derived from this matrix into the target matrix.
`boolean` ```epsilonEquals(GMatrix m1, double epsilon)```
Returns true if the L-infinite distance between this matrix and matrix m1 is less than or equal to the epsilon parameter, otherwise returns false.
`boolean` ```epsilonEquals(GMatrix m1, float epsilon)```
Deprecated.
`boolean` `equals(GMatrix m1)`
Returns true if all of the data members of GMatrix m1 are equal to the corresponding data members in this GMatrix.
`boolean` `equals(Object o1)`
Returns true if the Object o1 is of type GMatrix and all of the data members of o1 are equal to the corresponding data members in this GMatrix.
`void` `get(GMatrix m1)`
Places the values in the this GMatrix into the matrix m1; m1 should be at least as large as this GMatrix.
`void` `get(Matrix3d m1)`
Places the values in the upper 3x3 of this GMatrix into the matrix m1.
`void` `get(Matrix3f m1)`
Places the values in the upper 3x3 of this GMatrix into the matrix m1.
`void` `get(Matrix4d m1)`
Places the values in the upper 4x4 of this GMatrix into the matrix m1.
`void` `get(Matrix4f m1)`
Places the values in the upper 4x4 of this GMatrix into the matrix m1.
`void` ```getColumn(int col, double[] array)```
Places the values of the specified column into the array parameter.
`void` ```getColumn(int col, GVector vector)```
Places the values of the specified column into the vector parameter.
`double` ```getElement(int row, int column)```
Retrieves the value at the specified row and column of this matrix.
`int` `getNumCol()`
Returns the number of colmuns in this matrix.
`int` `getNumRow()`
Returns the number of rows in this matrix.
`void` ```getRow(int row, double[] array)```
Places the values of the specified row into the array parameter.
`void` ```getRow(int row, GVector vector)```
Places the values of the specified row into the vector parameter.
`int` `hashCode()`
Returns a hash code value based on the data values in this object.
`void` `identityMinus()`
Subtracts this matrix from the identity matrix and puts the values back into this (this = I - this).
`void` `invert()`
Inverts this matrix in place.
`void` `invert(GMatrix m1)`
Inverts matrix m1 and places the new values into this matrix.
`int` ```LUD(GMatrix LU, GVector permutation)```
LU Decomposition: this matrix must be a square matrix and the LU GMatrix parameter must be the same size as this matrix.
`void` `mul(GMatrix m1)`
Sets the value of this matrix to the result of multiplying itself with matrix m1 (this = this * m1).
`void` ```mul(GMatrix m1, GMatrix m2)```
Sets the value of this matrix to the result of multiplying the two argument matrices together (this = m1 * m2).
`void` ```mul(GVector v1, GVector v2)```
Computes the outer product of the two vectors; multiplies the the first vector by the transpose of the second vector and places the matrix result into this matrix.
`void` ```mulTransposeBoth(GMatrix m1, GMatrix m2)```
Multiplies the transpose of matrix m1 times the transpose of matrix m2, and places the result into this.
`void` ```mulTransposeLeft(GMatrix m1, GMatrix m2)```
Multiplies the transpose of matrix m1 times matrix m2, and places the result into this.
`void` ```mulTransposeRight(GMatrix m1, GMatrix m2)```
Multiplies matrix m1 times the transpose of matrix m2, and places the result into this.
`void` `negate()`
Negates the value of this matrix: this = -this.
`void` `negate(GMatrix m1)`
Sets the value of this matrix equal to the negation of of the GMatrix parameter.
`void` `set(double[] matrix)`
Sets the value of this matrix to the values found in the array parameter.
`void` `set(GMatrix m1)`
Sets the value of this matrix to the values found in matrix m1.
`void` `set(Matrix3d m1)`
Sets the value of this matrix to that of the Matrix3d provided.
`void` `set(Matrix3f m1)`
Sets the value of this matrix to that of the Matrix3f provided.
`void` `set(Matrix4d m1)`
Sets the value of this matrix to that of the Matrix4d provided.
`void` `set(Matrix4f m1)`
Sets the value of this matrix to that of the Matrix4f provided.
`void` ```setColumn(int col, double[] array)```
Copy the values from the array into the specified column of this matrix.
`void` ```setColumn(int col, GVector vector)```
Copy the values from the vector into the specified column of this matrix.
`void` ```setElement(int row, int column, double value)```
Modifies the value at the specified row and column of this matrix.
`void` `setIdentity()`
Sets this GMatrix to the identity matrix.
`void` ```setRow(int row, double[] array)```
Copy the values from the array into the specified row of this matrix.
`void` ```setRow(int row, GVector vector)```
Copy the values from the vector into the specified row of this matrix.
`void` `setScale(double scale)`
Sets this matrix to a uniform scale matrix; all of the values are reset.
`void` ```setSize(int nRow, int nCol)```
Changes the size of this matrix dynamically.
`void` `setZero()`
Sets all the values in this matrix to zero.
`void` `sub(GMatrix m1)`
Sets the value of this matrix to the matrix difference of itself and matrix m1 (this = this - m1).
`void` ```sub(GMatrix m1, GMatrix m2)```
Sets the value of this matrix to the matrix difference of matrices m1 and m2 (this = m1 - m2).
`int` ```SVD(GMatrix U, GMatrix W, GMatrix V)```
Finds the singular value decomposition (SVD) of this matrix such that this = U*W*transpose(V); and returns the rank of this matrix; the values of U,W,V are all overwritten.
`String` `toString()`
Returns a string that contains the values of this GMatrix.
`double` `trace()`
Returns the trace of this matrix.
`void` `transpose()`
Transposes this matrix in place.
`void` `transpose(GMatrix m1)`
Places the matrix values of the transpose of matrix m1 into this matrix.
• ### Methods inherited from class java.lang.Object

`finalize, getClass, notify, notifyAll, wait, wait, wait`
• ### Constructor Detail

• #### GMatrix

```public GMatrix(int nRow,
int nCol)```
Constructs an nRow by NCol identity matrix. Note that because row and column numbering begins with zero, nRow and nCol will be one larger than the maximum possible matrix index values.
Parameters:
`nRow` - number of rows in this matrix.
`nCol` - number of columns in this matrix.
• #### GMatrix

```public GMatrix(int nRow,
int nCol,
double[] matrix)```
Constructs an nRow by nCol matrix initialized to the values in the matrix array. The array values are copied in one row at a time in row major fashion. The array should be at least nRow*nCol in length. Note that because row and column numbering begins with zero, nRow and nCol will be one larger than the maximum possible matrix index values.
Parameters:
`nRow` - number of rows in this matrix.
`nCol` - number of columns in this matrix.
`matrix` - a 1D array that specifies a matrix in row major fashion
• #### GMatrix

`public GMatrix(GMatrix matrix)`
Constructs a new GMatrix and copies the initial values from the parameter matrix.
Parameters:
`matrix` - the source of the initial values of the new GMatrix
• ### Method Detail

• #### mul

`public final void mul(GMatrix m1)`
Sets the value of this matrix to the result of multiplying itself with matrix m1 (this = this * m1).
Parameters:
`m1` - the other matrix
• #### mul

```public final void mul(GMatrix m1,
GMatrix m2)```
Sets the value of this matrix to the result of multiplying the two argument matrices together (this = m1 * m2).
Parameters:
`m1` - the first matrix
`m2` - the second matrix
• #### mul

```public final void mul(GVector v1,
GVector v2)```
Computes the outer product of the two vectors; multiplies the the first vector by the transpose of the second vector and places the matrix result into this matrix. This matrix must be be as big or bigger than getSize(v1)xgetSize(v2).
Parameters:
`v1` - the first vector, treated as a row vector
`v2` - the second vector, treated as a column vector

`public final void add(GMatrix m1)`
Sets the value of this matrix to sum of itself and matrix m1.
Parameters:
`m1` - the other matrix

```public final void add(GMatrix m1,
GMatrix m2)```
Sets the value of this matrix to the matrix sum of matrices m1 and m2.
Parameters:
`m1` - the first matrix
`m2` - the second matrix
• #### sub

`public final void sub(GMatrix m1)`
Sets the value of this matrix to the matrix difference of itself and matrix m1 (this = this - m1).
Parameters:
`m1` - the other matrix
• #### sub

```public final void sub(GMatrix m1,
GMatrix m2)```
Sets the value of this matrix to the matrix difference of matrices m1 and m2 (this = m1 - m2).
Parameters:
`m1` - the first matrix
`m2` - the second matrix
• #### negate

`public final void negate()`
Negates the value of this matrix: this = -this.
• #### negate

`public final void negate(GMatrix m1)`
Sets the value of this matrix equal to the negation of of the GMatrix parameter.
Parameters:
`m1` - The source matrix
• #### setIdentity

`public final void setIdentity()`
Sets this GMatrix to the identity matrix.
• #### setZero

`public final void setZero()`
Sets all the values in this matrix to zero.
• #### identityMinus

`public final void identityMinus()`
Subtracts this matrix from the identity matrix and puts the values back into this (this = I - this).
• #### invert

`public final void invert()`
Inverts this matrix in place.
• #### invert

`public final void invert(GMatrix m1)`
Inverts matrix m1 and places the new values into this matrix. Matrix m1 is not modified.
Parameters:
`m1` - the matrix to be inverted
• #### copySubMatrix

```public final void copySubMatrix(int rowSource,
int colSource,
int numRow,
int numCol,
int rowDest,
int colDest,
GMatrix target)```
Copies a sub-matrix derived from this matrix into the target matrix. The upper left of the sub-matrix is located at (rowSource, colSource); the lower right of the sub-matrix is located at (lastRowSource,lastColSource). The sub-matrix is copied into the the target matrix starting at (rowDest, colDest).
Parameters:
`rowSource` - the top-most row of the sub-matrix
`colSource` - the left-most column of the sub-matrix
`numRow` - the number of rows in the sub-matrix
`numCol` - the number of columns in the sub-matrix
`rowDest` - the top-most row of the position of the copied sub-matrix within the target matrix
`colDest` - the left-most column of the position of the copied sub-matrix within the target matrix
`target` - the matrix into which the sub-matrix will be copied
• #### setSize

```public final void setSize(int nRow,
int nCol)```
Changes the size of this matrix dynamically. If the size is increased no data values will be lost. If the size is decreased, only those data values whose matrix positions were eliminated will be lost.
Parameters:
`nRow` - number of desired rows in this matrix
`nCol` - number of desired columns in this matrix
• #### set

`public final void set(double[] matrix)`
Sets the value of this matrix to the values found in the array parameter. The values are copied in one row at a time, in row major fashion. The array should be at least equal in length to the number of matrix rows times the number of matrix columns in this matrix.
Parameters:
`matrix` - the row major source array
• #### set

`public final void set(Matrix3f m1)`
Sets the value of this matrix to that of the Matrix3f provided.
Parameters:
`m1` - the matrix
• #### set

`public final void set(Matrix3d m1)`
Sets the value of this matrix to that of the Matrix3d provided.
Parameters:
`m1` - the matrix
• #### set

`public final void set(Matrix4f m1)`
Sets the value of this matrix to that of the Matrix4f provided.
Parameters:
`m1` - the matrix
• #### set

`public final void set(Matrix4d m1)`
Sets the value of this matrix to that of the Matrix4d provided.
Parameters:
`m1` - the matrix
• #### set

`public final void set(GMatrix m1)`
Sets the value of this matrix to the values found in matrix m1.
Parameters:
`m1` - the source matrix
• #### getNumRow

`public final int getNumRow()`
Returns the number of rows in this matrix.
Returns:
number of rows in this matrix
• #### getNumCol

`public final int getNumCol()`
Returns the number of colmuns in this matrix.
Returns:
number of columns in this matrix
• #### getElement

```public final double getElement(int row,
int column)```
Retrieves the value at the specified row and column of this matrix.
Parameters:
`row` - the row number to be retrieved (zero indexed)
`column` - the column number to be retrieved (zero indexed)
Returns:
the value at the indexed element
• #### setElement

```public final void setElement(int row,
int column,
double value)```
Modifies the value at the specified row and column of this matrix.
Parameters:
`row` - the row number to be modified (zero indexed)
`column` - the column number to be modified (zero indexed)
`value` - the new matrix element value
• #### getRow

```public final void getRow(int row,
double[] array)```
Places the values of the specified row into the array parameter.
Parameters:
`row` - the target row number
`array` - the array into which the row values will be placed
• #### getRow

```public final void getRow(int row,
GVector vector)```
Places the values of the specified row into the vector parameter.
Parameters:
`row` - the target row number
`vector` - the vector into which the row values will be placed
• #### getColumn

```public final void getColumn(int col,
double[] array)```
Places the values of the specified column into the array parameter.
Parameters:
`col` - the target column number
`array` - the array into which the column values will be placed
• #### getColumn

```public final void getColumn(int col,
GVector vector)```
Places the values of the specified column into the vector parameter.
Parameters:
`col` - the target column number
`vector` - the vector into which the column values will be placed
• #### get

`public final void get(Matrix3d m1)`
Places the values in the upper 3x3 of this GMatrix into the matrix m1.
Parameters:
`m1` - The matrix that will hold the new values
• #### get

`public final void get(Matrix3f m1)`
Places the values in the upper 3x3 of this GMatrix into the matrix m1.
Parameters:
`m1` - The matrix that will hold the new values
• #### get

`public final void get(Matrix4d m1)`
Places the values in the upper 4x4 of this GMatrix into the matrix m1.
Parameters:
`m1` - The matrix that will hold the new values
• #### get

`public final void get(Matrix4f m1)`
Places the values in the upper 4x4 of this GMatrix into the matrix m1.
Parameters:
`m1` - The matrix that will hold the new values
• #### get

`public final void get(GMatrix m1)`
Places the values in the this GMatrix into the matrix m1; m1 should be at least as large as this GMatrix.
Parameters:
`m1` - The matrix that will hold the new values
• #### setRow

```public final void setRow(int row,
double[] array)```
Copy the values from the array into the specified row of this matrix.
Parameters:
`row` - the row of this matrix into which the array values will be copied.
`array` - the source array
• #### setRow

```public final void setRow(int row,
GVector vector)```
Copy the values from the vector into the specified row of this matrix.
Parameters:
`row` - the row of this matrix into which the array values will be copied
`vector` - the source vector
• #### setColumn

```public final void setColumn(int col,
double[] array)```
Copy the values from the array into the specified column of this matrix.
Parameters:
`col` - the column of this matrix into which the array values will be copied
`array` - the source array
• #### setColumn

```public final void setColumn(int col,
GVector vector)```
Copy the values from the vector into the specified column of this matrix.
Parameters:
`col` - the column of this matrix into which the array values will be copied
`vector` - the source vector
• #### mulTransposeBoth

```public final void mulTransposeBoth(GMatrix m1,
GMatrix m2)```
Multiplies the transpose of matrix m1 times the transpose of matrix m2, and places the result into this.
Parameters:
`m1` - The matrix on the left hand side of the multiplication
`m2` - The matrix on the right hand side of the multiplication
• #### mulTransposeRight

```public final void mulTransposeRight(GMatrix m1,
GMatrix m2)```
Multiplies matrix m1 times the transpose of matrix m2, and places the result into this.
Parameters:
`m1` - The matrix on the left hand side of the multiplication
`m2` - The matrix on the right hand side of the multiplication
• #### mulTransposeLeft

```public final void mulTransposeLeft(GMatrix m1,
GMatrix m2)```
Multiplies the transpose of matrix m1 times matrix m2, and places the result into this.
Parameters:
`m1` - The matrix on the left hand side of the multiplication
`m2` - The matrix on the right hand side of the multiplication
• #### transpose

`public final void transpose()`
Transposes this matrix in place.
• #### transpose

`public final void transpose(GMatrix m1)`
Places the matrix values of the transpose of matrix m1 into this matrix.
Parameters:
`m1` - the matrix to be transposed (but not modified)
• #### toString

`public String toString()`
Returns a string that contains the values of this GMatrix.
Overrides:
`toString` in class `Object`
Returns:
the String representation
• #### hashCode

`public int hashCode()`
Returns a hash code value based on the data values in this object. Two different GMatrix objects with identical data values (i.e., GMatrix.equals returns true) will return the same hash number. Two GMatrix objects with different data members may return the same hash value, although this is not likely.
Overrides:
`hashCode` in class `Object`
Returns:
the integer hash code value
• #### equals

`public boolean equals(GMatrix m1)`
Returns true if all of the data members of GMatrix m1 are equal to the corresponding data members in this GMatrix.
Parameters:
`m1` - The matrix with which the comparison is made.
Returns:
true or false
• #### equals

`public boolean equals(Object o1)`
Returns true if the Object o1 is of type GMatrix and all of the data members of o1 are equal to the corresponding data members in this GMatrix.
Overrides:
`equals` in class `Object`
Parameters:
`o1` - The object with which the comparison is made.
Returns:
true or false
• #### epsilonEquals

```public boolean epsilonEquals(GMatrix m1,
float epsilon)```
• #### epsilonEquals

```public boolean epsilonEquals(GMatrix m1,
double epsilon)```
Returns true if the L-infinite distance between this matrix and matrix m1 is less than or equal to the epsilon parameter, otherwise returns false. The L-infinite distance is equal to MAX[i=0,1,2, . . .n ; j=0,1,2, . . .n ; abs(this.m(i,j) - m1.m(i,j)]
Parameters:
`m1` - The matrix to be compared to this matrix
`epsilon` - the threshold value
• #### trace

`public final double trace()`
Returns the trace of this matrix.
Returns:
the trace of this matrix
• #### SVD

```public final int SVD(GMatrix U,
GMatrix W,
GMatrix V)```
Finds the singular value decomposition (SVD) of this matrix such that this = U*W*transpose(V); and returns the rank of this matrix; the values of U,W,V are all overwritten. Note that the matrix V is output as V, and not transpose(V). If this matrix is mxn, then U is mxm, W is a diagonal matrix that is mxn, and V is nxn. Using the notation W = diag(w), then the inverse of this matrix is: inverse(this) = V*diag(1/w)*tranpose(U), where diag(1/w) is the same matrix as W except that the reciprocal of each of the diagonal components is used.
Parameters:
`U` - The computed U matrix in the equation this = U*W*transpose(V)
`W` - The computed W matrix in the equation this = U*W*transpose(V)
`V` - The computed V matrix in the equation this = U*W*transpose(V)
Returns:
The rank of this matrix.
• #### LUD

```public final int LUD(GMatrix LU,
GVector permutation)```
LU Decomposition: this matrix must be a square matrix and the LU GMatrix parameter must be the same size as this matrix. The matrix LU will be overwritten as the combination of a lower diagonal and upper diagonal matrix decompostion of this matrix; the diagonal elements of L (unity) are not stored. The GVector parameter records the row permutation effected by the partial pivoting, and is used as a parameter to the GVector method LUDBackSolve to solve sets of linear equations. This method returns +/- 1 depending on whether the number of row interchanges was even or odd, respectively.
Parameters:
`LU` - The matrix into which the lower and upper decompositions will be placed.
`permutation` - The row permutation effected by the partial pivoting
Returns:
+-1 depending on whether the number of row interchanges was even or odd respectively
• #### setScale

`public final void setScale(double scale)`
Sets this matrix to a uniform scale matrix; all of the values are reset.
Parameters:
`scale` - The new scale value
• #### clone

`public Object clone()`
Creates a new object of the same class as this object.
Overrides:
`clone` in class `Object`
Returns:
a clone of this instance.
Throws:
`OutOfMemoryError` - if there is not enough memory.
Since:
vecmath 1.3
`Cloneable`