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LSpice
LSpice
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shifted Shifted QR algorithm--whyalgorithm—why does the shift help  ?  

I read that a way to speed up the convergence rate of the QR algorithm is to shift the target matrix. It is not so clear to me why this helps. The convergence rate depends on the minimum gap between consecutive eigenvalues, but if we shift $A$ to $A + cI$, the gaps remain the same  ?

shifted QR algorithm--why does the shift help  ?  

I read that a way to speed up the convergence rate of the QR algorithm is to shift the target matrix. It is not so clear to me why this helps. The convergence rate depends on the minimum gap between consecutive eigenvalues, but if we shift $A$ to $A + cI$, the gaps remain the same  ?

Shifted QR algorithm—why does the shift help?

I read that a way to speed up the convergence rate of the QR algorithm is to shift the target matrix. It is not so clear to me why this helps. The convergence rate depends on the minimum gap between consecutive eigenvalues, but if we shift $A$ to $A + cI$, the gaps remain the same?

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Darsh Ranjan
Darsh Ranjan
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vanvu
vanvu
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shifted QR algorithm--why does the shift help ?

I read that a way to speed up the convergence rate of the QR algorithm is to shift the target matrix. It is not so clear to me why this helps. The convergence rate depends on the minimum gap between consecutive eigenvalues, but if we shift $A$ to $A + cI$, the gaps remain the same ?