bio  website  fph.altervista.org 

location  Pisa, Italy  
age  32  
visits  member for  5 years, 5 months 
seen  12 mins ago  
stats  profile views  2,370 
Numerical linear algebra. Mainly matrix equations and their applications (control theory, applied probability).
(This profile was written for Mathoverflow, but Stack Exchange insists on copying it over verbatim to other sites, where it makes less sense.)
2h

reviewed  Approve A Question on 1, 2 ,3 Conjecture 
4h

reviewed  Approve Source for roots of matrix polynomials? 
Apr 21 
reviewed  Approve determinants tag wiki excerpt 
Apr 21 
revised 
Functional minimization problem
better title 
Apr 21 
comment 
LQR solution when there are linear terms in the cost function?
In the LQR problems I have studied $s$ and $u$ are either sequences or functions of a real variable. Is this the case here, too? Could you please write the full equations, if so? 
Apr 20 
awarded  Popular Question 
Apr 19 
reviewed  Approve descriptivesettheory tag wiki excerpt 
Apr 19 
reviewed  Approve Zero divisors and boundary elements of $A^{1}$ 
Apr 9 
accepted  Noncomputational software useful to mathematicians 
Apr 9 
accepted  Factorizing a block symmetric matrix 
Apr 9 
accepted  Should I become a Mathscinet reviewer? 
Apr 9 
accepted  Positive definite to nonnegative 
Apr 9 
answered  The bubble function 
Apr 1 
comment 
Solving $Ax=e_k$ for standard basis vector $e_k$, sparse $A$
Also, the numbers given in the question sound strange. If I am not mistaken with the computations, 0.00001% of nonzeros means that there are $10^7$ nonzeros in the matrix overall, one every 1000 rows. Is that the case? Would it make sense to prune out the zero rows first? 
Apr 1 
comment 
Solving $Ax=e_k$ for standard basis vector $e_k$, sparse $A$
QR seems out of question to me. Its result typically is a dense, floatingpoint number matrix, which would require 800 Terabytes only to store it. 
Mar 29 
revised 
Lagrangian submanifold of a CalabiYau manifold
expanded abbreviation in the title, for clarity 
Mar 27 
answered  Two equivalent descriptions of a physical system yielding a nontrivial mathematical formula 
Mar 25 
answered  The maximal eigenvalue of a symmetric Toeplitz matrix 
Mar 24 
awarded  Enlightened 
Mar 24 
awarded  Nice Answer 