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Added MatrixFastPower.java with changes

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DDullahan
2018-08-30 21:52:20 +08:00
parent f713a5ff9c
commit 55c179bf19
1 changed files with 80 additions and 28 deletions
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108
DataStructures/Matrix/MatrixFastPower.java
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@ -1,5 +1,3 @@
import java.util.*;
/**
*
* Java implementation of Matrix fast power
@ -14,11 +12,67 @@ import java.util.*;
* other Matrix basic operator is based on @author Kyler Smith, 2017
*
* @author DDullahan, 2018
*
*
*/
class MatrixFastPower {
/**
* Matrix Fast Power
*
* @param matrix : square Matrix
* @param k : power of Matrix
* @return product
*/
public static Matrix FastPower(Matrix matrix, int k) throws RuntimeException {
if(matrix.getColumns() != matrix.getRows())
throw new RuntimeException("Matrix is not square Matrix.");
int[][] newData = new int[matrix.getColumns()][matrix.getRows()];
for(int i = 0; i < matrix.getColumns(); i++)
newData[i][i] = 1;
Matrix newMatrix = new Matrix(newData),
coMatrix = new Matrix(matrix.data);
while(k != 0) {
if((k & 1) != 0)
newMatrix = newMatrix.multiply(coMatrix);
k >>= 1;
coMatrix = coMatrix.multiply(coMatrix);
}
return newMatrix;
}
public static void main(String[] argv) {
int[][] data = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
Matrix matrix = new Matrix(data);
System.out.println("original matrix : ");
System.out.println(matrix.toString());
matrix = MatrixFastPower.FastPower(matrix, 5);
System.out.println("after power : ");
System.out.println(matrix.toString());
matrix = MatrixFastPower.FastPower(matrix, 1000000);
System.out.println("notice, large power may cause overflow : ");
System.out.print(matrix.toString());
System.out.println("you can use mod to fix that :-) ");
}
}
class Matrix {
private int[][] data;
public int[][] data;
/**
* Constructor for the matrix takes in a 2D array
@ -106,34 +160,32 @@ class Matrix {
}
/**
* Matrix Fast Power
*
* @param k : power of Matrix
* @return product
*/
public Matrix MatrixFastPower(int k) throws RuntimeException {
* Returns the Matrix as a String in the following format
*
* [ a b c ] ...
* [ x y z ] ...
* [ i j k ] ...
* ...
*
* @return Matrix as String
* TODO: Work formatting for different digit sizes
*/
public String toString() {
String str = "";
if(this.getColumns() != this.getRows())
throw new RuntimeException("Matrix is not square Matrix.");
for(int i = 0; i < this.data.length; i++) {
str += "[ ";
int[][] newData = new int[this.getColumns()][this.getRows()];
for(int i = 0; i < this.getColumns(); i++)
newData[i][i] = 1;
Matrix newMatrix = new Matrix(newData),
coMatrix = new Matrix(this.data);
while(k != 0) {
if((k & 1) != 0)
newMatrix = newMatrix.multiply(coMatrix);
k >>= 1;
coMatrix = coMatrix.multiply(coMatrix);
for(int j = 0; j < this.data[0].length; j++) {
str += data[i][j];
str += " ";
}
str += "]";
str += "\n";
}
return newMatrix;
return str;
}
}