CODEWITHSUNDEEP
c++eigeneigen3
rjgill
rjgill

Reputation: 23

Eigen C++ : extracting a block from DiagonalMatrix type

I'm trying to extract a submatrix from an Eigen::DiagonalMatrix type, but block is not a member of type Eigen::DiagonalMatrix.

Eigen::DiagonalMatrix<double, 7> A;

...

(void) A.block<6,6>(0,0); // fails, block is not a member of Eigen::DiagonalMatrix

Is there another way to extract a submatrix of type DiagonalMatrix?

Upvotes: 1

Views: 85

Answers (1)

Homer512
Homer512

Reputation: 13295

A diagonal matrix is just a wrapper around a vector with the diagonal entries. You can access this vector with the diagonal() method. So you can use this:

Eigen::DiagonalMatrix<double, 7> A;
A.diagonal().head<6>().asDiagonal();

Upvotes: 1

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