Numpy MaskedArray.dot() function | Python
numpy.MaskedArray.dot() function is used to calculate the dot product of two mask arrays.
Syntax :
numpy.ma.dot(arr1, arr2, strict=False)Parameters:
arr1, arr2:[ ndarray] Inputs arrays.
strict : [bool, optional] Whether masked data are propagated (True) or set to 0 (False) for the computation. Default is False.Return : [ ndarray] The dot product of arr1 and arr2.
Code #1 :
# Python program explaining # numpy.MaskedArray.dot() method # importing numpy as geek # and numpy.ma module as ma import numpy as geek import numpy.ma as ma # creating input arrays in_arr1 = geek.array([[1, 2], [ 3, 4]]) print ("1st Input array : ", in_arr1) in_arr2 = geek.array([[-1, -2], [ -3, -4]]) print ("2nd Input array : ", in_arr2) # Now we are creating masked array. # by making entry as invalid mask_arr1 = ma.masked_array(in_arr1, mask = [[ 1, 0], [ 0, 1]]) print ("1st Masked array : ", mask_arr1) mask_arr2 = ma.masked_array(in_arr2, mask =[[ 0, 1], [ 0, 0]]) print ("2nd Masked array : ", mask_arr2) # applying MaskedArray.dot methods # to masked array out_arr = ma.dot(mask_arr1, mask_arr2) print ("Dot product of two arrays : ", out_arr) |
Output:
1st Input array : [[1 2] [3 4]] 2nd Input array : [[-1 -2] [-3 -4]] 1st Masked array : [[-- 2] [3 --]] 2nd Masked array : [[-1 --] [-3 -4]] Dot product of two arrays : [[-6 -8] [-3 --]]
Code #2 :
# Python program explaining # numpy.MaskedArray.dot() method # importing numpy as geek # and numpy.ma module as ma import numpy as geek import numpy.ma as ma # creating input arrays in_arr1 = geek.array([[1, 2], [ 3, -1], [ 5, -3]]) print ("1st Input array : ", in_arr1) in_arr2 = geek.array([[1, 0, 3], [ 4, 1, 6]]) print ("2nd Input array : ", in_arr2) # Now we are creating masked array. # by making entry as invalid mask_arr1 = ma.masked_array(in_arr1, mask = [[ 1, 0], [ 0, 1], [ 0, 0]]) print ("1st Masked array : ", mask_arr1) mask_arr2 = ma.masked_array(in_arr2, mask =[[ 0, 0, 0], [ 0, 0, 1]]) print ("2nd Masked array : ", mask_arr2) # applying MaskedArray.dot methods # to masked array out_arr = ma.dot(mask_arr1, mask_arr2) print ("Dot product of two arrays : ", out_arr) |
Output:
1st Input array : [[ 1 2] [ 3 -1] [ 5 -3]] 2nd Input array : [[1 0 3] [4 1 6]] 1st Masked array : [[-- 2] [3 --] [5 -3]] 2nd Masked array : [[1 0 3] [4 1 --]] Dot product of two arrays : [[8 2 --] [3 0 9] [-7 -3 15]]
