How could I subtract a 1xN eigen matrix from a MxN matrix, like numpy does?
I could not summarize a 1xN matrix from a MxN matrix like I do in numpy.
I create a matrix of np.arange(9).reshape(3,3) with eigen like this:
int buf[9];
for (int i{0}; i < 9; ++i) {
buf[i] = i;
}
m = Map<MatrixXi>(buf, 3,3);
Then I compute mean along row direction:
m2 = m.rowwise().mean();
I would like to broadcast m2 to 3x3 matrix, and subtract it from m, how could I do this?
c++ eigen
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
add a comment |
I could not summarize a 1xN matrix from a MxN matrix like I do in numpy.
I create a matrix of np.arange(9).reshape(3,3) with eigen like this:
int buf[9];
for (int i{0}; i < 9; ++i) {
buf[i] = i;
}
m = Map<MatrixXi>(buf, 3,3);
Then I compute mean along row direction:
m2 = m.rowwise().mean();
I would like to broadcast m2 to 3x3 matrix, and subtract it from m, how could I do this?
c++ eigen
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
add a comment |
I could not summarize a 1xN matrix from a MxN matrix like I do in numpy.
I create a matrix of np.arange(9).reshape(3,3) with eigen like this:
int buf[9];
for (int i{0}; i < 9; ++i) {
buf[i] = i;
}
m = Map<MatrixXi>(buf, 3,3);
Then I compute mean along row direction:
m2 = m.rowwise().mean();
I would like to broadcast m2 to 3x3 matrix, and subtract it from m, how could I do this?
c++ eigen
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
I could not summarize a 1xN matrix from a MxN matrix like I do in numpy.
I create a matrix of np.arange(9).reshape(3,3) with eigen like this:
int buf[9];
for (int i{0}; i < 9; ++i) {
buf[i] = i;
}
m = Map<MatrixXi>(buf, 3,3);
Then I compute mean along row direction:
m2 = m.rowwise().mean();
I would like to broadcast m2 to 3x3 matrix, and subtract it from m, how could I do this?
c++ eigen
c++ eigen
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
edited Jan 3 at 11:37
Matthieu Brucher
16.9k32244
16.9k32244
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
asked Jan 3 at 11:32
coin cheungcoin cheung
1347
1347
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
You need to use appropriate types for your values, MatrixXi lacks the vector operations (such as broadcasting). You also seem to have the bad habit of declaring your variables well before you initialise them. Don't.
This should work
std::array<int, 9> buf;
std::iota(buf.begin(), buf.end(), 0);
auto m = Map<Matrix3i>(buf.data());
auto v = m.rowwise().mean();
auto result = m.colwise() - v;
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
add a comment |
There is no numpy-like broadcasting available in Eigen, what you can do is reuse the same pattern that you used:
m.colwise() -= m2
(See Eigen tutorial on this)
N.B.: m2 needs to be a vector, not a matrix. Also the more fixed the dimensions, the better the compiler can generate efficient code.
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
I dom.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.
– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
Did you use-=or-?
– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
@coincheung what is the type ofm2? it can't be (an alias for)Matrix<int, Dynamic, Dynamic>, it has to beMatrix<int, 1, /*N or Dynamic*/>
– Caleth
Jan 3 at 12:36
|
show 2 more comments
While the .colwise() method already suggested should be preferred in this case, it is actually also possible to broadcast a vector to multiple columns using the replicate method.
m -= m2.replicate<1,3>();
// or
m -= m2.rowwise().replicate<3>();
If 3 is not known at compile time, you can write
m -= m2.rowwise().replicate(m.cols());
answered Jan 9 at 14:36
chtzchtz
7,61411235
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f54021457%2fhow-could-i-subtract-a-1xn-eigen-matrix-from-a-mxn-matrix-like-numpy-does%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
You need to use appropriate types for your values, MatrixXi lacks the vector operations (such as broadcasting). You also seem to have the bad habit of declaring your variables well before you initialise them. Don't.
This should work
std::array<int, 9> buf;
std::iota(buf.begin(), buf.end(), 0);
auto m = Map<Matrix3i>(buf.data());
auto v = m.rowwise().mean();
auto result = m.colwise() - v;
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
add a comment |
You need to use appropriate types for your values, MatrixXi lacks the vector operations (such as broadcasting). You also seem to have the bad habit of declaring your variables well before you initialise them. Don't.
This should work
std::array<int, 9> buf;
std::iota(buf.begin(), buf.end(), 0);
auto m = Map<Matrix3i>(buf.data());
auto v = m.rowwise().mean();
auto result = m.colwise() - v;
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
add a comment |
You need to use appropriate types for your values, MatrixXi lacks the vector operations (such as broadcasting). You also seem to have the bad habit of declaring your variables well before you initialise them. Don't.
This should work
std::array<int, 9> buf;
std::iota(buf.begin(), buf.end(), 0);
auto m = Map<Matrix3i>(buf.data());
auto v = m.rowwise().mean();
auto result = m.colwise() - v;
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
You need to use appropriate types for your values, MatrixXi lacks the vector operations (such as broadcasting). You also seem to have the bad habit of declaring your variables well before you initialise them. Don't.
This should work
std::array<int, 9> buf;
std::iota(buf.begin(), buf.end(), 0);
auto m = Map<Matrix3i>(buf.data());
auto v = m.rowwise().mean();
auto result = m.colwise() - v;
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
edited Jan 3 at 13:38
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
answered Jan 3 at 12:43
CalethCaleth
18.5k22142
18.5k22142
add a comment |
add a comment |
There is no numpy-like broadcasting available in Eigen, what you can do is reuse the same pattern that you used:
m.colwise() -= m2
(See Eigen tutorial on this)
N.B.: m2 needs to be a vector, not a matrix. Also the more fixed the dimensions, the better the compiler can generate efficient code.
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
I dom.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.
– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
Did you use-=or-?
– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
@coincheung what is the type ofm2? it can't be (an alias for)Matrix<int, Dynamic, Dynamic>, it has to beMatrix<int, 1, /*N or Dynamic*/>
– Caleth
Jan 3 at 12:36
|
show 2 more comments
There is no numpy-like broadcasting available in Eigen, what you can do is reuse the same pattern that you used:
m.colwise() -= m2
(See Eigen tutorial on this)
N.B.: m2 needs to be a vector, not a matrix. Also the more fixed the dimensions, the better the compiler can generate efficient code.
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
I dom.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.
– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
Did you use-=or-?
– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
@coincheung what is the type ofm2? it can't be (an alias for)Matrix<int, Dynamic, Dynamic>, it has to beMatrix<int, 1, /*N or Dynamic*/>
– Caleth
Jan 3 at 12:36
|
show 2 more comments
There is no numpy-like broadcasting available in Eigen, what you can do is reuse the same pattern that you used:
m.colwise() -= m2
(See Eigen tutorial on this)
N.B.: m2 needs to be a vector, not a matrix. Also the more fixed the dimensions, the better the compiler can generate efficient code.
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
There is no numpy-like broadcasting available in Eigen, what you can do is reuse the same pattern that you used:
m.colwise() -= m2
(See Eigen tutorial on this)
N.B.: m2 needs to be a vector, not a matrix. Also the more fixed the dimensions, the better the compiler can generate efficient code.
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
edited Jan 3 at 13:46
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
answered Jan 3 at 11:42
Matthieu BrucherMatthieu Brucher
16.9k32244
16.9k32244
I dom.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.
– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
Did you use-=or-?
– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
@coincheung what is the type ofm2? it can't be (an alias for)Matrix<int, Dynamic, Dynamic>, it has to beMatrix<int, 1, /*N or Dynamic*/>
– Caleth
Jan 3 at 12:36
|
show 2 more comments
I dom.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.
– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
Did you use-=or-?
– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
@coincheung what is the type ofm2? it can't be (an alias for)Matrix<int, Dynamic, Dynamic>, it has to beMatrix<int, 1, /*N or Dynamic*/>
– Caleth
Jan 3 at 12:36
I do
m.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.– coin cheung
Jan 3 at 11:51
I do
m.rowwise() - m2, but only got the error of ** static assertion failed: YOU_TRIED_CALLING_A_VECTOR_METHOD_ON_A_MATRIX EIGEN_STATIC_ASSERT_VECTOR_ONLY(OtherDerived)**.– coin cheung
Jan 3 at 11:51
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
It seems we cannot let one matrix minus another matrix, when they have different shapes.
– coin cheung
Jan 3 at 11:52
1
1
Did you use
-= or -?– Matthieu Brucher
Jan 3 at 12:01
Did you use
-= or -?– Matthieu Brucher
Jan 3 at 12:01
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
I see no difference here actually.
– coin cheung
Jan 3 at 12:22
1
1
@coincheung what is the type of
m2? it can't be (an alias for) Matrix<int, Dynamic, Dynamic>, it has to be Matrix<int, 1, /*N or Dynamic*/>– Caleth
Jan 3 at 12:36
@coincheung what is the type of
m2? it can't be (an alias for) Matrix<int, Dynamic, Dynamic>, it has to be Matrix<int, 1, /*N or Dynamic*/>– Caleth
Jan 3 at 12:36
|
show 2 more comments
While the .colwise() method already suggested should be preferred in this case, it is actually also possible to broadcast a vector to multiple columns using the replicate method.
m -= m2.replicate<1,3>();
// or
m -= m2.rowwise().replicate<3>();
If 3 is not known at compile time, you can write
m -= m2.rowwise().replicate(m.cols());
answered Jan 9 at 14:36
chtzchtz
7,61411235
add a comment |
While the .colwise() method already suggested should be preferred in this case, it is actually also possible to broadcast a vector to multiple columns using the replicate method.
m -= m2.replicate<1,3>();
// or
m -= m2.rowwise().replicate<3>();
If 3 is not known at compile time, you can write
m -= m2.rowwise().replicate(m.cols());
answered Jan 9 at 14:36
chtzchtz
7,61411235
add a comment |
While the .colwise() method already suggested should be preferred in this case, it is actually also possible to broadcast a vector to multiple columns using the replicate method.
m -= m2.replicate<1,3>();
// or
m -= m2.rowwise().replicate<3>();
If 3 is not known at compile time, you can write
m -= m2.rowwise().replicate(m.cols());
answered Jan 9 at 14:36
chtzchtz
7,61411235
While the .colwise() method already suggested should be preferred in this case, it is actually also possible to broadcast a vector to multiple columns using the replicate method.
m -= m2.replicate<1,3>();
// or
m -= m2.rowwise().replicate<3>();
If 3 is not known at compile time, you can write
m -= m2.rowwise().replicate(m.cols());
answered Jan 9 at 14:36
chtzchtz
7,61411235
answered Jan 9 at 14:36
chtzchtz
7,61411235
answered Jan 9 at 14:36
chtzchtz
7,61411235
answered Jan 9 at 14:36
chtzchtz
7,61411235
7,61411235
add a comment |
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f54021457%2fhow-could-i-subtract-a-1xn-eigen-matrix-from-a-mxn-matrix-like-numpy-does%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
