Matrix notation, continued
–?u(x,y) = 0 ? Au=b with
i=0, j=0 ? u0,0 u–1,0 + u0,–1
... ...
i=0, 0<j<n–1 ? u0,j u–1,j
... ...
i=0, j=n–1 ? u0,n–1 u–1,n–1 + u0,n
... ...
0<i<m–1, j=0 ? ui,0 ui,–1
... ...
0<i<m–1, 0<j<n–1 ? u = ui,j b = 0
... ...
0<i<m–1, j=n–1 ? ui,n–1 ui,n
... ...
i=m–1, j=0 ? um–1,0 um,0 + um–1,–1
... ...
i=m–1, 0<j<n–1 ? um–1,j um,j
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i=m–1, j=n–1 ? um–1,n–1 um, n–1 + um–1,n