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Matrix product of a 2D (first argument) and a 1D array (second argument) in Numpy
To find the matrix product of a 2D and a 1D array, use the numpy.matmul() method in Python Numpy. If the second argument is 1-D, it is promoted to a matrix by appending a 1 to its dimensions. After matrix multiplication the appended 1 is removed.
Returns the matrix product of the inputs. This is a scalar only when both x1, x2 are 1-d vectors. The out is a location into which the result is stored. If provided, it must have a shape that matches the signature (n,k),(k,m)->(n,m). If not provided or None, a freshly-allocated array is returned.
Steps
At first, import the required library −
import numpy as np
Create a 2D and a 1D array −
arr1 = np.array([[5, 7], [10, 15]]) arr2 = np.array([25, 35])
Display the arrays −
print("Array 1 (Two Dimensional)...
", arr1) print("
Array 2 (One Dimensional)...
", arr2)
Get the type of the arrays −
print("
Our Array 1 type...
", arr1.dtype) print("
Our Array 2 type...
", arr2.dtype)
Get the dimensions of the Arrays −
print("
Our Array 1 Dimensions...
",arr1.ndim) print("
Our Array 2 Dimensions...
",arr2.ndim)
Get the shape of the Arrays −
print("
Our Array 1 Shape...
",arr1.shape) print("
Our Array 2 Shape...
",arr2.shape)
To find the matrix product of a 2D and a 1D array, use the numpy.matmul() method in Python Numpy. If the second argument is 1-D, it is promoted to a matrix by appending a 1 to its dimensions. After matrix multiplication the appended 1 is removed −
print("
Result (matrix product)...
",np.matmul(arr1, arr2))
Example
import numpy as np # Create a 2D and a 1D array arr1 = np.array([[5, 7], [10, 15]]) arr2 = np.array([25, 35]) # Display the arrays print("Array 1 (Two Dimensional)...
", arr1) print("
Array 2 (One Dimensional)...
", arr2) # Get the type of the arrays print("
Our Array 1 type...
", arr1.dtype) print("
Our Array 2 type...
", arr2.dtype) # Get the dimensions of the Arrays print("
Our Array 1 Dimensions...
",arr1.ndim) print("
Our Array 2 Dimensions...
",arr2.ndim) # Get the shape of the Arrays print("
Our Array 1 Shape...
",arr1.shape) print("
Our Array 2 Shape...
",arr2.shape) # To find the matrix product of a 2D and a 1D array, use the numpy.matmul() method in Python Numpy # If the second argument is 1-D, it is promoted to a matrix by appending a 1 to its dimensions. # After matrix multiplication the appended 1 is removed. print("
Result (matrix product)...
",np.matmul(arr1, arr2))
Output
Array 1 (Two Dimensional)... [[ 5 7] [10 15]] Array 2 (One Dimensional)... [25 35] Our Array 1 type... int64 Our Array 2 type... int64 Our Array 1 Dimensions... 2 Our Array 2 Dimensions... 1 Our Array 1 Shape... (2, 2) Our Array 2 Shape... (2,) Result (matrix product)... [370 775]