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## Re: Successive Over-Relaxation ... what is wrong? Improvements?

 From: Joza Subject: Re: Successive Over-Relaxation ... what is wrong? Improvements? Date: Sun, 4 Nov 2012 05:24:05 -0800 (PST)

```Here is my textbook's implementation of the Algorithm which I followed:
The sparse matrix structure a contains val, col, row, d ie. 4 arrays
containing non-zero values, column indices of those values, where each row
starts, and the diagonal values. (I haven't done this part exactly as I
figured it wouldn't make a difference since Octave stores the matrix I
created anyway as a sparse matrix...right?...)

for k := 1 to maxits do
normx := 0; dnormx := 0
for i := 1 to n do
sum : = 0
for j :=rowstart[i ] to rowstart[i + 1] − 1 do
sum := sum + val [ j ] × x [ col [ j ] ]
endfor j
delx := ω × (b[i ] − sum)/d[i ]
x [i ] := x [i ] + delx
normx := max(normx, abs( x [i ]) )
dnormx := max(dnormx, abs(delx ) )
endfor i
if dnormx ≤ tol + 4 × m × normx then return (x, k)
endfor k

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```