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feat: Add support for determinant calculation (#131)
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This pull request includes several feature updates and documentation improvements to enhance the functionality and usability of the JMatrix library, especially focusing on adding support for determinant calculation.

Signed-off-by: Ryuu Mitsuki <dhefam31@gmail.com>
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@mitsuki31
mitsuki31 committed Sep 13, 2024
2 parents 654cb32 + bee7566 commit f80d147
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114 changes: 113 additions & 1 deletion src/main/java/com/mitsuki/jmatrix/Matrix.java
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import com.mitsuki.jmatrix.core.MatrixChecker;
import com.mitsuki.jmatrix.core.MatrixUtils;
import com.mitsuki.jmatrix.core.MatrixDeterminant;
import com.mitsuki.jmatrix.exception.IllegalMatrixSizeException;
import com.mitsuki.jmatrix.exception.InvalidIndexException;
import com.mitsuki.jmatrix.exception.JMatrixBaseException;
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*
* @author <a href="https://github.com/mitsuki31" target="_blank">
* Ryuu Mitsuki</a>
* @version 3.3, 12 September 2024
* @version 3.4, 13 September 2024
* @since 0.1.0
* @license <a href="https://www.apache.org/licenses/LICENSE-2.0" target="_blank">
* Apache License 2.0</a>
Expand Down Expand Up @@ -201,6 +202,7 @@ public class Matrix implements MatrixUtils {
:: MATRIX CONSTRUCTORS
::
=========================================*/
// region Constructors


/**
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:: MATRIX SPECIAL CONSTRUCTORS
::
=========================================*/
// region Special Constructors

/*--------------------------
:: Create
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:: MATRIX OPERATIONS
::
=========================================*/
// region Matrix Operations


/*--------------------------
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}


/*--------------------------
:: Determinant Matrix
--------------------------*/

/**
* Calculates the determinant of the matrix.
*
* <p>This method calls the static method {@link Matrix#determinant(Matrix)} to calculate
* the determinant of this matrix.
*
* <p>It will automatically chooses the best algorithm for calculating the determinant
* based on the size of the matrix. If the matrix is smaller than {@code 4x4}, this method
* uses the cofactor expansion algorithm. Otherwise, it uses Gaussian elimination.
*
* @return The determinant of the matrix.
*
* @throws NullMatrixException
* If the matrix is {@code null}.
* @throws IllegalMatrixSizeException
* If the matrix is not a square matrix.
*
* @implNote
* This method is just a wrapper for {@link Matrix#determinant(Matrix)}. It is more convenient
* to call this method directly on the matrix instance instead of calling the static method.
*
* @since 1.5.0
* @see #determinant(Matrix)
* @see MatrixDeterminant#determinant_CofactorExpansion(Matrix)
* @see MatrixDeterminant#determinant_GaussElimination(Matrix)
*/
public double determinant() {
return Matrix.determinant(this);
}

/**
* Calculates the determinant of the given matrix.
*
* <p>This method automatically chooses the best algorithm for calculating the determinant
* based on the size of the matrix. If the matrix is smaller than {@code 4x4}, this method
* uses the cofactor expansion algorithm. Otherwise, it uses Gaussian elimination.
*
* @param m The matrix to calculate the determinant of.
* @return The determinant of the matrix.
*
* @throws NullMatrixException
* If the matrix is {@code null} or contains {@code null} references.
* @throws IllegalMatrixSizeException
* If the matrix is not a square matrix.
*
* @since 1.5.0
* @see #determinant(double[][])
* @see MatrixDeterminant#determinant_CofactorExpansion(Matrix)
* @see MatrixDeterminant#determinant_GaussElimination(Matrix)
*/
public static double determinant(Matrix m) {
if (MatrixUtils.isNullEntries(m)) {
raise(new NullMatrixException(
"Matrix is null. Please ensure the matrix are initialized")
);
}

if (m.getNumRows() <= 4) { // Not larger than 4x4
// Cofactor expansion is faster for smaller matrices
return MatrixDeterminant.determinant_CofactorExpansion(m);
} else {
return MatrixDeterminant.determinant_GaussElimination(m);
}
}

/**
* Calculates the determinant of the given matrix.
*
* <p>This method automatically chooses the best algorithm for calculating the determinant
* based on the size of the matrix. If the matrix is smaller than {@code 4x4}, this method
* uses the cofactor expansion algorithm. Otherwise, it uses Gaussian elimination.
*
* @param a The 2D array representation of the matrix to calculate the determinant of.
* @return The determinant of the matrix.
*
* @throws NullMatrixException
* If the matrix is {@code null} or contains {@code null} references.
* @throws IllegalMatrixSizeException
* If the matrix is not a square matrix.
*
* @since 1.5.0
* @see #determinant(Matrix)
* @see MatrixDeterminant#determinant_CofactorExpansion(double[][])
* @see MatrixDeterminant#determinant_GaussElimination(double[][])
*/
public static double determinant(double[][] a) {
if (a == null || a.length == 0) {
raise(new NullMatrixException(
"Matrix is null. Please ensure the matrix are initialized")
);
}

if (a.length <= 4) { // Not larger than 4x4
// Cofactor expansion is faster for smaller matrices
return MatrixDeterminant.determinant_CofactorExpansion(a);
} else {
return MatrixDeterminant.determinant_GaussElimination(a);
}
}


/*=========================================
::
:: MATRIX TYPE CHECKERS
::
=========================================*/
// region Type Checkers


/*---------------------------
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:: ADDITIONAL / UTILITIES METHODS
::
=========================================*/
// region Utilities Methods


/*---------------------------
Expand Down Expand Up @@ -5225,6 +5336,7 @@ final public static void display(double[ ][ ] arr, int index) {
:: OVERRIDEN METHODS
::
=========================================*/
// region Overriden Methods


/**
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7 changes: 6 additions & 1 deletion src/main/java/com/mitsuki/jmatrix/core/DoubleArray2DChecker.java
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* to be created to use its methods and provides static methods for checking matrix properties
* such as nullity, squareness, diagonalness, and identity.
*
* @since 1.5.0
* @since 1.5.0
* @version 1.0, 12 September 2024
* @author <a href="https://github.com/mitsuki31" target="_blank">
* Ryuu Mitsuki</a>
* @license <a href="https://www.apache.org/licenses/LICENSE-2.0" target="_blank">
* Apache License 2.0</a>
*/
public class DoubleArray2DChecker {
/** Hide the constructor because it is a static class */
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7 changes: 6 additions & 1 deletion src/main/java/com/mitsuki/jmatrix/core/MatrixChecker.java
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* the properties of matrices. It extends the {@link DoubleArray2DChecker} class and provides
* static methods for checking matrix properties such as nullity, squareness, diagonalness, and identity.
*
* @since 1.5.0
* @since 1.5.0
* @version 1.0, 12 September 2024
* @author <a href="https://github.com/mitsuki31" target="_blank">
* Ryuu Mitsuki</a>
* @license <a href="https://www.apache.org/licenses/LICENSE-2.0" target="_blank">
* Apache License 2.0</a>
*/
public class MatrixChecker extends DoubleArray2DChecker {
/** Hide the constructor because it is a static class */
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