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Shift invert iteration

Thread starter kiso
Start date Jan 9, 2002

Status: Not open for further replies.

Jan 9, 2002

kiso

Structural

Hi

I'm having problems with the shift invert iteration. I can't understand how the matrix A-sI is computed. If "s" is a coifficient (computed with Rayleighs quotient for etc.) then the product sI for a 3x3 matrix would be

s 0 0
0 s 0
0 0 s right????

Is it this simple, because it doesn't work?
Without the shift "s" my program works.

Thanks
Kim