Elementwise Matrix Multiplication in R

In a matrix, as we know rows are the ones that run horizontally and columns are the ones that run vertically. In this article, we are going to perform element-wise matrix multiplication in R programming.

Approach

• Create a matrix
• Multiply two matrices
• Verify the result.

Element-wise multiplication using “*” operator:

Syntax: matrix1*matrix*2…..matrix n

Example 1:

This code shows the element-wise multiplication of two matrices data1 and data2, Data comprises 5 rows and 2 columns:

R

# Creating matrices 10 elements each using
# range operator ":"
data1 <- matrix(1:10, nrow = 5)
print(data1)

data2 <- matrix(11:20, nrow = 5)
print(data2)

# perform element wise multiplication
print(data1*data2)

Output:

Example 2:

This code for multiplication of multiple matrices data1,data2,data3. All data comprises 5 rows created using the range operator.

R

# Creating matrices 10 elements each
# using range operator ":"
data1 <- matrix(1:10, nrow = 5)
print(data1)

data2 <- matrix(11:20, nrow = 5)
print(data2)

data3 <- matrix(21:30, nrow = 5)

# perform element wise multiplication
print(data1*data2*data3)

Output:

Example 3:

This code shows the matrix is created using vectors. And matrix multiplication is done.

R

# vector a
a = c(3, 4, 5, 6, 7, 8)

# vector b
b=c(1, 3, 0, 7, 8, 5)

# Creating matrices using vector
data1 <- matrix(a, nrow = 3)
print(data1)

data2 <- matrix(b, nrow = 3)
print(data2)

print(data1*data2)

Output:

Example 4:

An example that shows multiplication column arrangement and matrices data1 and data2 and multiplied. Column wise we are going to perform matrix multiplication data1 and data2 comprises 3 columns and elements are created using vector.

R

# vector a
a = c(3, 4, 5, 6, 7, 8)

# vector b
b = c(1, 3, 0, 7, 8, 5)

# Creating matrices using vector
data1 <- matrix(a, ncol = 3)
print(data1)

data2 <- matrix(b, ncol = 3)
print(data2)

print(data1*data2)

Output: