h-matrix theory and its applications ljiljana cvetković university of novi sad
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H-matrix theory H-matrix theory and its applicationsand its applications
Ljiljana CvetkoviLjiljana Cvetkovićć
University of Novi SadUniversity of Novi Sad
IntroductionIntroduction
Subclasses of H-matrices Subclasses of H-matrices Diagonal scalingDiagonal scaling
Approximation of Minimal GerApproximation of Minimal Gerššgorin setgorin set Improving convergence area of relaxation Improving convergence area of relaxation
methodsmethods Improving bounds for determinantsImproving bounds for determinantsSimplification of proving matrix propertiesSimplification of proving matrix properties
Subdirect sumsSubdirect sums Schur complement invariantsSchur complement invariants
Reverse questionReverse question
H-matricesH-matrices
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H-matrixH-matrix M-matrixM-matrix
Diagonal scalingDiagonal scaling
A is H-matrixA is H-matrix
AX is SDD matrixAX is SDD matrix
AA XX
structure of Xstructure of X
unknownunknown knownknown
Subclasses of H-matricesSubclasses of H-matricesS S
_
SDD
|aii|(|akk|- rk+|aki|) > ri|aki|
Dashnic
S-SDD
|aii|> ri
|aii|> riS |akk|> rk
S
(|aii|- riS)(|akk|- rk
S) > riS rk
S -
-
-
Subclasses of H-matricesSubclasses of H-matricesS S
_
SDD
|aii|(|akk|- rk+|aki|) > ri|aki|
Dashnic
S-SDD
|aii|> ri
x
x
1
1
1
1
1
xx
1
1
1
1
1
1
1
x1
1
1
1
1
1
1
|aii|> riS |akk|> rk
S
(|aii|- riS)(|akk|- rk
S) > riS rk
S -
-
-
Benefits from H-Benefits from H-subclassessubclasses
Approximation of Minimal GerApproximation of Minimal Gerššgorin gorin setset
( )A
( )D A
( )C A
MGS
H
B all nonsingular
diagonal matrices
B all diagonal
el. 1 or x>0
B all diagonal el. 1
except one
B
B
S-SDD
Dash
SDD
…explicit forms…
Benefits from H-Benefits from H-subclassessubclasses
Improving convergence area of relaxation Improving convergence area of relaxation methodsmethodsAOR method AOR method
SDD case ~ convergence area SDD case ~ convergence area ΩΩ(A)(A)
H-case ~ convergence area H-case ~ convergence area ΩΩ(A(AXX))
HereHere XX depends on one real parameterdepends on one real parameter xx, , which belongs to an which belongs to an admissible admissible area, so area, so ΩΩ(A(AXX) = ) = ΘΘ((xx)) SDD case ~ convergence area max SDD case ~ convergence area max ΘΘ((xx))
xx
x=1 always x=1 always includedincluded
IMPROVEMENTIMPROVEMENT
... next... next
Vladimir KostiVladimir Kostić ć
S-SDD Class of Matrices and its S-SDD Class of Matrices and its Applications Applications
Benefits from H-Benefits from H-subclassessubclasses
Improving bounds for Improving bounds for determinantsdeterminants
Lower boundsLower bounds
SDD case ~ SDD case ~ det(A)det(A) ≥ ≥ εε(A)(A)
H-case ~ H-case ~ det(A) det(A) det(det(XX)) ≥ ≥ εε(A(AXX))
εε(A(AXX) = f() = f(xx))
x=1 always x=1 always includedincluded
IMPROVEMENTIMPROVEMENT
... next... next
Vladimir KostiVladimir Kostić ć
S-SDD Class of Matrices and its S-SDD Class of Matrices and its Applications Applications
SDD case ~ det(A) SDD case ~ det(A) ≥≥ max [max f( max [max f(xx) / ) / xxkk]] xxkk
Benefits from H-Benefits from H-subclassessubclassesSimplification of proving matrix Simplification of proving matrix propertiesproperties
Subdirect sumsSubdirect sums
Schur complement invariantsSchur complement invariants
……next after nextnext after next
Maja Kovačević Maja Kovačević
Dashnic-Zusmanovich Class of Matrices Dashnic-Zusmanovich Class of Matrices and its Applicationsand its Applications
Reverse questionReverse question
Scaling with diagonal matrices of a Scaling with diagonal matrices of a special form special form
Characterization of new H-subclassesCharacterization of new H-subclasses
??
Reverse question : YESReverse question : YES
Then: Then:
Even better approximation of Minimal GerEven better approximation of Minimal Gerššgorin gorin setset Furthet improvement of relaxation methods Furthet improvement of relaxation methods convergence area convergence area Further improvement of bounds for determinantsFurther improvement of bounds for determinants Simplification of proving more matrix propertiesSimplification of proving more matrix properties
Recent referencesRecent references
Cvetković, Kostić: Between Geršgorin and minimal Geršgorin sets. J. Comput. Appl. Math. 2006
Cvetković, Kostić, Varga: A new Geršgorin type eigenvalue inclusion area. ETNA 2004
Cvetković, Kostić: A note on the convergence of the AOR method. Appl. Math. Comput. 2007
Cvetković, Kostić: New subclasses of block H-matrices with applications to parallel decomposition-type relaxation methods. Numer. Algor. 2006
Cvetković: H matrix Theory vs. Eigenvalue Localization. Numer. Algor. 2006
www.im.ns.ac.yu/events/ala2008
Applied Linear AlgebraApplied Linear Algebra
–– in honor of Ivo Marek – in honor of Ivo Marek –
April 28-30, 2008 Novi SadApril 28-30, 2008 Novi Sad
Future references…Future references…
ALA 2005ALA 2005
Thank you!Thank you!
DěkujiDěkuji!!
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