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Apr
17
revised About the spectral radius of a kind of matrices
added 161 characters in body
Apr
17
comment Cholesky decomposition
Cholesky decomposition implies positive-semidefiniteness. Consider $A=0$ and $B=1$, then the new block matrix is not positive semidefinite.
Apr
17
revised Prove or disprove: the spectral radius of a matrix with negative entries and row sums as 1 is larger than 1
added 224 characters in body
Apr
17
comment Prove or disprove: the spectral radius of a matrix with negative entries and row sums as 1 is larger than 1
I've updated the question at math.stackexchange.com/q/364427/11014
Apr
17
asked About the spectral radius of a kind of matrices
Apr
17
comment Prove or disprove: the spectral radius of a matrix with negative entries and row sums as 1 is larger than 1
Hmm...the problem I've actually met seems to have some implied constraints. Anyway thanks for the answer.
Apr
17
accepted Prove or disprove: the spectral radius of a matrix with negative entries and row sums as 1 is larger than 1
Apr
17
asked Prove or disprove: the spectral radius of a matrix with negative entries and row sums as 1 is larger than 1
Apr
16
asked Textbooks on modern optimization (on machine learning) with exercises
Feb
5
comment The positive-definite-ness of RBF kernel
@user1551 As I mentioned, I am calculating $\log\det$. Simply calling $\det$ will produce zero, while summing up the logarithm of eigenvalues is OK for large $\alpha$ since no eigenvalue will be calculated as negative.
Feb
5
revised The positive-definite-ness of RBF kernel
added 41 characters in body
Feb
2
comment The positive-definite-ness of RBF kernel
@user1551 Then how to calculate it? RBF kernel is quite common I think there should be some robust algorithms.
Feb
1
asked The positive-definite-ness of RBF kernel
Jan
7
awarded  Popular Question
Oct
25
awarded  Announcer
Oct
21
asked Questions about algebraic manifold on matrices
Oct
7
revised How can I get sequence $4,4,2,4,4,2,4,4,2\ldots$ into equation?
TeXification
Oct
7
awarded  Custodian
Oct
7
reviewed Reviewed How can I get sequence $4,4,2,4,4,2,4,4,2\ldots$ into equation?
Oct
7
suggested suggested edit on How can I get sequence $4,4,2,4,4,2,4,4,2\ldots$ into equation?