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HOMEWORK

(1a, September 5. Will be collected with 1b at the end of the month) Code the Jacobi method to solve the linear system Au=b, where A is a matrix with -2 down the diagonal, 1 on the sub- and super-diagonals, and b=0. Fix the conditions tex2html_wrap_inline72 (start with 0 and 1 resp). You can solve the equation exactly, to test your code. The question to address is When to stop iterating? For purposes here, compute the residual tex2html_wrap_inline74 , and iterate until tex2html_wrap_inline76 is small. We'll be more precise as the semester proceeds.

(1b, September 12. To be collected with 1a on Sept. 26) Given an invertible matrix A, the matrix iteration

displaymath78

will converge to A^-1. One effective choice of X^0 is a scaled transpose of A, namely

displaymath80

and s is a scale factor greater than 1, and tex2html_wrap_inline82 .

Using the same A as in part 1a, solve Au=b by (approximately) inverting A according to this iteration.

Compare the number of operations each method involves. Use the time command to get an idea of how each method scales as you increase from say O(10^2) to O(10^4) components.

See COR502 notes and references therein.

November 14-16 Dr. Jeff Tilson of CCR will present 2 lectures, discussing the IBM SP and parallel debugging.

Nov 30. Professor Ken Hoffmann of the School of Medicine will be speaking at the coloquium. abstract



PROJECT Foxes, rabbits and grass. DUE December 11,4:30 p.m. turn work into my mailbox in the math department.


E. Bruce Pitman
Wed Sep 13 22:27:10 EDT 2000