Numpy: adding n-dimensional vector to m-dimensional vector to get (n, m) matrix
Suppose I have the array [1,2,3,4,5].
I want to "add" the array [2,4,6,8] to it so I get
[[3,5,7,9],
[4,6,8,10],
[5,7,9,11],
[6,8,10,12],
[7,9,11,13]]
(or its transpose).
There is probably a function for this but I can't seem to find it because I'm not sure what to search for.
numpy numpy-broadcasting numpy-ndarray
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
add a comment |
Suppose I have the array [1,2,3,4,5].
I want to "add" the array [2,4,6,8] to it so I get
[[3,5,7,9],
[4,6,8,10],
[5,7,9,11],
[6,8,10,12],
[7,9,11,13]]
(or its transpose).
There is probably a function for this but I can't seem to find it because I'm not sure what to search for.
numpy numpy-broadcasting numpy-ndarray
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
Search forouter add.
– Divakar
Nov 23 '18 at 17:00
Great, thank you!
– J. doe
Nov 23 '18 at 17:53
add a comment |
Suppose I have the array [1,2,3,4,5].
I want to "add" the array [2,4,6,8] to it so I get
[[3,5,7,9],
[4,6,8,10],
[5,7,9,11],
[6,8,10,12],
[7,9,11,13]]
(or its transpose).
There is probably a function for this but I can't seem to find it because I'm not sure what to search for.
numpy numpy-broadcasting numpy-ndarray
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
Suppose I have the array [1,2,3,4,5].
I want to "add" the array [2,4,6,8] to it so I get
[[3,5,7,9],
[4,6,8,10],
[5,7,9,11],
[6,8,10,12],
[7,9,11,13]]
(or its transpose).
There is probably a function for this but I can't seem to find it because I'm not sure what to search for.
numpy numpy-broadcasting numpy-ndarray
numpy numpy-broadcasting numpy-ndarray
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
asked Nov 23 '18 at 16:59
J. doeJ. doe
61
61
Search forouter add.
– Divakar
Nov 23 '18 at 17:00
Great, thank you!
– J. doe
Nov 23 '18 at 17:53
add a comment |
Search forouter add.
– Divakar
Nov 23 '18 at 17:00
Great, thank you!
– J. doe
Nov 23 '18 at 17:53
Search for
outer add.– Divakar
Nov 23 '18 at 17:00
Search for
outer add.– Divakar
Nov 23 '18 at 17:00
Great, thank you!
– J. doe
Nov 23 '18 at 17:53
Great, thank you!
– J. doe
Nov 23 '18 at 17:53
add a comment |
1 Answer
1
active
oldest
votes
As suggested by @Divakar, the best way is to use add.outer:
a1 = np.array([1,2,3,4,5])
a2 = np.array([2,4,6,8])
np.add.outer(a1,a2)
But you can also explicitely broadcast your a1 array to the proper shape, then add to a2:
a1[:,None]+a2
# essentially equivalent to:
# a1.reshape(-1,1)+a2
Both produce:
array([[ 3, 5, 7, 9],
[ 4, 6, 8, 10],
[ 5, 7, 9, 11],
[ 6, 8, 10, 12],
[ 7, 9, 11, 13]])
answered Nov 23 '18 at 17:14
saculsacul
30k41740
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
As suggested by @Divakar, the best way is to use add.outer:
a1 = np.array([1,2,3,4,5])
a2 = np.array([2,4,6,8])
np.add.outer(a1,a2)
But you can also explicitely broadcast your a1 array to the proper shape, then add to a2:
a1[:,None]+a2
# essentially equivalent to:
# a1.reshape(-1,1)+a2
Both produce:
array([[ 3, 5, 7, 9],
[ 4, 6, 8, 10],
[ 5, 7, 9, 11],
[ 6, 8, 10, 12],
[ 7, 9, 11, 13]])
answered Nov 23 '18 at 17:14
saculsacul
30k41740
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
add a comment |
As suggested by @Divakar, the best way is to use add.outer:
a1 = np.array([1,2,3,4,5])
a2 = np.array([2,4,6,8])
np.add.outer(a1,a2)
But you can also explicitely broadcast your a1 array to the proper shape, then add to a2:
a1[:,None]+a2
# essentially equivalent to:
# a1.reshape(-1,1)+a2
Both produce:
array([[ 3, 5, 7, 9],
[ 4, 6, 8, 10],
[ 5, 7, 9, 11],
[ 6, 8, 10, 12],
[ 7, 9, 11, 13]])
answered Nov 23 '18 at 17:14
saculsacul
30k41740
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
add a comment |
As suggested by @Divakar, the best way is to use add.outer:
a1 = np.array([1,2,3,4,5])
a2 = np.array([2,4,6,8])
np.add.outer(a1,a2)
But you can also explicitely broadcast your a1 array to the proper shape, then add to a2:
a1[:,None]+a2
# essentially equivalent to:
# a1.reshape(-1,1)+a2
Both produce:
array([[ 3, 5, 7, 9],
[ 4, 6, 8, 10],
[ 5, 7, 9, 11],
[ 6, 8, 10, 12],
[ 7, 9, 11, 13]])
answered Nov 23 '18 at 17:14
saculsacul
30k41740
As suggested by @Divakar, the best way is to use add.outer:
a1 = np.array([1,2,3,4,5])
a2 = np.array([2,4,6,8])
np.add.outer(a1,a2)
But you can also explicitely broadcast your a1 array to the proper shape, then add to a2:
a1[:,None]+a2
# essentially equivalent to:
# a1.reshape(-1,1)+a2
Both produce:
array([[ 3, 5, 7, 9],
[ 4, 6, 8, 10],
[ 5, 7, 9, 11],
[ 6, 8, 10, 12],
[ 7, 9, 11, 13]])
answered Nov 23 '18 at 17:14
saculsacul
30k41740
answered Nov 23 '18 at 17:14
saculsacul
30k41740
answered Nov 23 '18 at 17:14
saculsacul
30k41740
answered Nov 23 '18 at 17:14
saculsacul
30k41740
30k41740
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
add a comment |
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
Thank you! This is exactly what I was looking for.
– J. doe
Nov 23 '18 at 17:54
add a comment |
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Search for
outer add.– Divakar
Nov 23 '18 at 17:00
Great, thank you!
– J. doe
Nov 23 '18 at 17:53