Multiply Matrix by Vector in R

A matrix is a 2-dimensional structure whereas a vector is a one-dimensional structure. In this article, we are going to multiply the given matrix by the given vector using R Programming Language. Multiplication between the two occurs when vector elements are multiplied with matrix elements column-wise.

Approach:

• Create a matrix
• Create a vector
• Multiply them
• Display result.

Method 1: Naive method

Once the structures are ready we directly multiply them using the multiplication operator(*).

Example:

Output:

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Example 2:

Output:

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Example 3:

This code has both matrix and vector has equal size

Output:

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Method 2: Using sweep()

we can use sweep() method to multiply vectors to a matrix. sweep() function is used to apply the operation “+ or - or '*' or '/' ” to the row or column in the given matrix.

Syntax:

sweep(data, MARGIN,  FUN)

Parameter:

• data=input matrix
• MARGIN: MARGIN = 2 means row; MARGIN = 1 means column.
• FUN: The operation that has to be done (e.g. + or - or * or /)

Here, we are performing "*" operation

Example:

Output:

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Example 2:

Output:

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