For working professionals
For fresh graduates
More
6. JDK in Java
7. C++ Vs Java
16. Java If-else
18. Loops in Java
20. For Loop in Java
45. Packages in Java
52. Java Collection
55. Generics In Java
56. Java Interfaces
59. Streams in Java
62. Thread in Java
66. Deadlock in Java
73. Applet in Java
74. Java Swing
75. Java Frameworks
77. JUnit Testing
80. Jar file in Java
81. Java Clean Code
85. Java 8 features
86. String in Java
92. HashMap in Java
97. Enum in Java
100. Hashcode in Java
104. Linked List in Java
108. Array Length in Java
110. Split in java
111. Map In Java
114. HashSet in Java
117. DateFormat in Java
120. Java List Size
121. Java APIs
127. Identifiers in Java
129. Set in Java
131. Try Catch in Java
132. Bubble Sort in Java
134. Queue in Java
141. Jagged Array in Java
143. Java String Format
144. Replace in Java
145. charAt() in Java
146. CompareTo in Java
150. parseInt in Java
152. Abstraction in Java
153. String Input in Java
155. instanceof in Java
156. Math Floor in Java
157. Selection Sort Java
158. int to char in Java
163. Deque in Java
171. Trim in Java
172. RxJava
173. Recursion in Java
174. HashSet Java
176. Square Root in Java
189. Javafx
Matrix multiplication in Java is the process of multiplying two matrices together. As a result, a new matrix is created with the results. It involves three steps. First, it iterates through the rows and columns of the matrices. Second, it multiplies the corresponding elements. Finally, it gathers the results to generate the resulting matrix.
In this tutorial, we will deal with the various concepts related to matrix multiplication in Java, Java programs to multiply two matrices, multiplication using for loops, and Java programs to multiply two matrices of any size, among other concepts.
Matrix multiplication is an arithmetic operation performed on matrices to obtain a new matrix by multiplying corresponding elements and summing the results. In Java, we can perform matrix multiplication with the help of nested loops to iterate over the elements of the matrices and apply the multiplication rule.
In the above example, matrix1 is a 2x3 matrix, and matrix2 is a 3x2 matrix. After performing the matrix multiplication, the resulting matrix will be a 2x2 matrix. The program prints the elements of the resulting matrix as the output.
Code:
public class upGradTutorials {
public static void main(String[] args) {
int[][] matrix1 = {{1, 2, 3}, {4, 5, 6}}; // 2x3 matrix
int[][] matrix2 = {{7, 8}, {9, 10}, {11, 12}}; // 3x2 matrix
int rowsMatrix1 = matrix1.length;
int columnsMatrix1 = matrix1[0].length;
int columnsMatrix2 = matrix2[0].length;
// Create a new matrix to store the multiplication result
int[][] resultMatrix = new int[rowsMatrix1][columnsMatrix2];
// Perform matrix multiplication
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
for (int k = 0; k < columnsMatrix1; k++) {
resultMatrix[i][j] += matrix1[i][k] * matrix2[k][j];
}
}
}
// Print the result matrix
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
System.out.print(resultMatrix[i][j] + " ");
}
System.out.println();
}
}
}
We start by defining two matrices, matrix1, and matrix2, with their respective dimensions. We determine the number of rows and columns for each matrix using the length property of arrays. We create a new matrix, resultMatrix, with dimensions equal to the number of rows in matrix1 and the number of columns in matrix2.
We use nested loops to perform the matrix multiplication. The outer loops iterate over the rows of matrix1 and the columns of matrix2. The inner loop iterates over the columns of matrix1 (or the rows of matrix2). Inside the innermost loop, we multiply the corresponding elements of matrix1 and matrix2 and accumulate the result in the corresponding position of resultMatrix.
Finally, we print the elements of resultMatrix to display the resulting matrix.
Here is the syntax for performing matrix multiplication in Java:
int[][] matrix1 = {
{element, element, element},
{element, element, element},
{element, element, element}
};
int[][] matrix2 = {
{element, element, element},
{element, element, element},
{element, element, element}
};
if (matrix1[0].length != matrix2.length) {
System.out.println("Matrix multiplication is not possible.");
return;
}
int[][] resultMatrix = new int[matrix1.length][matrix2[0].length];
for (int i = 0; i < matrix1.length; i++) {
for (int j = 0; j < matrix2[0].length; j++) {
int sum = 0;
for (int k = 0; k < matrix1[0].length; k++) {
sum += matrix1[i][k] * matrix2[k][j];
}
resultMatrix[i][j] = sum;
}
}
In this program, we have two 2x2 matrices, matrix1 and matrix2. Like the previous program, it checks if the matrices are compatible for multiplication. If they are not compatible, it displays a message and exits.
If the matrices are compatible, the program creates a new matrix resultMatrix to store the multiplication result. It uses nested loops to iterate over the rows and columns of the matrices. For each element of the resulting matrix, it calculates the sum of the products of corresponding elements from the input matrices.
The calculated sum is then assigned to the corresponding position in resultMatrix. Finally, it prints the elements of resultMatrix, representing the product of the two matrices. You can modify the values and dimensions of matrix1 and matrix2 to perform matrix multiplication for different matrices.
Code:
public class upGradTutorials {
public static void main(String[] args) {
int[][] matrix1 = {{1, 2}, {3, 4}}; // 2x2 matrix
int[][] matrix2 = {{5, 6}, {7, 8}}; // 2x2 matrix
int rowsMatrix1 = matrix1.length;
int columnsMatrix1 = matrix1[0].length;
int rowsMatrix2 = matrix2.length;
int columnsMatrix2 = matrix2[0].length;
if (columnsMatrix1 != rowsMatrix2) {
System.out.println("Matrix multiplication is not possible.");
return;
}
int[][] resultMatrix = new int[rowsMatrix1][columnsMatrix2];
// Perform matrix multiplication
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
int sum = 0;
for (int k = 0; k < columnsMatrix1; k++) {
sum += matrix1[i][k] * matrix2[k][j];
}
resultMatrix[i][j] = sum;
}
}
// Print the resulting matrix
System.out.println("Resulting matrix:");
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
System.out.print(resultMatrix[i][j] + " ");
}
System.out.println();
}
}
}
In the above program, we have two matrices matrix1 and matrix2. We first check the compatibility of matrices for multiplication by comparing the number of columns in matrix1 with the number of rows in matrix2. If they are incompatible, it displays a message and exits the program.
If the matrices are compatible, we create a new matrix resultMatrix to store the multiplication result. We use three nested for loops to iterate over the rows and columns of the matrices.
For each element of the resulting matrix, we calculate the sum of the products of corresponding elements from matrix1 and matrix2. The calculated sum is then assigned to the corresponding position in resultMatrix. Finally, we print the elements of resultMatrix, which represents the product of the two matrices.
Code:
public class upGradTutorials {
public static void main(String[] args) {
int[][] matrix1 = {
{1, 2, 3},
{4, 5, 6}
};
int[][] matrix2 = {
{7, 8},
{9, 10},
{11, 12}
};
int rowsMatrix1 = matrix1.length;
int columnsMatrix1 = matrix1[0].length;
int rowsMatrix2 = matrix2.length;
int columnsMatrix2 = matrix2[0].length;
if (columnsMatrix1 != rowsMatrix2) {
System.out.println("Matrix multiplication is not possible.");
return;
}
int[][] resultMatrix = new int[rowsMatrix1][columnsMatrix2];
// Perform matrix multiplication
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
int sum = 0;
for (int k = 0; k < columnsMatrix1; k++) {
sum += matrix1[i][k] * matrix2[k][j];
}
resultMatrix[i][j] = sum;
}
}
// Print the resulting matrix
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
System.out.print(resultMatrix[i][j] + " ");
}
System.out.println();
}
}
}
This program follows a similar structure as the previous one. However, instead of using a separate variable to store the sum of products, we directly accumulate the result in the resultMatrix. This avoids unnecessary assignments and improves the efficiency of the multiplication process.
The innermost loop iterates over the common dimension of the matrices (columnsMatrix1 in matrix1 and rowsMatrix2 in matrix2). The elements from matrix1 and matrix2 are multiplied, and the result is added to the corresponding position in resultMatrix.
Finally, the program prints the elements of resultMatrix, which represents the product of the two matrices
This approach is more efficient because it reduces the number of variable assignments and eliminates the need for an intermediate sum variable.
Code:
public class upGradTutorials {
public static void main(String[] args) {
int[][] matrix1 = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
int[][] matrix2 = {
{10, 11},
{12, 13},
{14, 15}
};
int rowsMatrix1 = matrix1.length;
int columnsMatrix1 = matrix1[0].length;
int rowsMatrix2 = matrix2.length;
int columnsMatrix2 = matrix2[0].length;
if (columnsMatrix1 != rowsMatrix2) {
System.out.println("Matrix multiplication is not possible.");
return;
}
int[][] resultMatrix = new int[rowsMatrix1][columnsMatrix2];
// Perform matrix multiplication
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
for (int k = 0; k < columnsMatrix1; k++) {
resultMatrix[i][j] += matrix1[i][k] * matrix2[k][j];
}
}
}
// Print the resulting matrix
for (int i = 0; i < rowsMatrix1; i++) {
for (int j = 0; j < columnsMatrix2; j++) {
System.out.print(resultMatrix[i][j] + " ");
}
System.out.println();
}
}
}
Matrix multiplication is a fundamental operation in Java. It has many applications in maths and computer science. It serves as a handy tool for performing calculations. It also helps in transformations on multiple dimensions of data.
If you wish to learn more about matrix multiplication in Java, enroll in a credible course in computer science. Online learning platforms like upGrad provide the best-in-class courses for aspiring computer science experts. Visit upGrad to learn more.
1. Can matrices of different sizes be multiplied?
No, matrices of different sizes cannot be multiplied. For it to multiply, the number of columns in the first matrix must be the same as the number of rows in the second matrix.
2. How can I handle exceptions during matrix multiplication?
You can handle exceptions in Java by using try-catch blocks. For example, if the matrices have incompatible sizes for multiplication, you can catch an exception and handle it appropriately, such as displaying an error message or taking alternative actions.
3. Are there any optimization techniques for matrix multiplication in Java?
Yes, there are various optimization techniques for matrix multiplication, such as Strassen's algorithm or parallelization using multi-threading. These techniques can improve the efficiency of matrix multiplication for large matrices.
Take the Free Quiz on Java
Answer quick questions and assess your Java knowledge
Author
Talk to our experts. We are available 7 days a week, 9 AM to 12 AM (midnight)
Indian Nationals
1800 210 2020
Foreign Nationals
+918045604032
1.The above statistics depend on various factors and individual results may vary. Past performance is no guarantee of future results.
2.The student assumes full responsibility for all expenses associated with visas, travel, & related costs. upGrad does not provide any a.