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Algorithm for Computation

The solution to the finite difference scheme is obtained through recursive back-substitution.

Equation 31 - is solved by,
\begin{eqnarray}
A_{ij}^{n+\frac{1}{2}}= g_{22}\,(\mathbf{s}^n_{ij}) 
\quad
 C_{...
 ...athbf{s}^n_{ij})\;\mathbf{S}_{ij}(u^n)\;+\;\mathbf{P}_{ij}\,(u^n).\end{eqnarray}
(43)
The solution for a fixed number j in range $1 \le j \le N-1$obtained through,
\begin{eqnarray}
u^{n+1/2}_{ij}= \alpha^{n+1/2}_{i+1j}\; u^{n+\frac{1}{2}}_{i+1\...
 ...
i=1,N-1,&
\;\;\;\;\;\;\;\;
u^{n+\frac{1}{2}}_{Nj} = \phi_1(1,jh),\end{eqnarray} (44)
where,
\begin{eqnarray}
\alpha^{n+1/2}_{i+1j}= \frac{B_{ij}^{n+\frac{1}{2}}}{C_{ij}^{n+...
 ...,N-1, &
\quad
\beta^{n+\frac{1}{2}}_{0j} = \phi_1(0,jh). \nonumber\end{eqnarray}

Equation 32 - is solved by,
\begin{eqnarray}
A_{ij}^{n+\frac{1}{2}}= g_{22}\,(\mathbf{s}^n_{ij}) 
\quad
 C_{...
 ...athbf{s}^n_{ij})\;\mathbf{S}_{ij}(v^n)\;+\;\mathbf{P}_{ij}\,(v^n).\end{eqnarray}
(45)
The solution for a fixed j in range $1 \le j \le N-1$ is obtained through,
\begin{eqnarray}
v^{n+1/2}_{ij}= \alpha^{n+1/2}_{i+1j}\; v^{n+\frac{1}{2}}_{i+1\...
 ...
i=1,N-1,&
\;\;\;\;\;\;\;\;
v^{n+\frac{1}{2}}_{Nj} = \phi_2(1,jh),\end{eqnarray} (46)
where,
\begin{eqnarray}
\alpha^{n+1/2}_{i+1j}= \frac{B_{ij}^{n+\frac{1}{2}}}{C_{ij}^{n+...
 ...1,N-1, &
\quad
\beta^{n+\frac{1}{2}}_{0j} = \phi_2(0,jh) \nonumber\end{eqnarray}

Equation 33 - is solved by,
\begin{eqnarray}
A_{ij}^{n+\frac{1}{2}}= g_{11}\,(\mathbf{s}^n_{ij}) 
\quad
 C_{...
 ...^{n+1/2}_{ij}
- g_{11}\,(\mathbf{s}^n_{ij})\;\mathbf{S}_{ij}(u^n).\end{eqnarray}
(47)
The solution for a fixed i in the range $1 \le i \le N-1$ is obtained through,
\begin{eqnarray}
u^{n+1}_{ij}= \alpha^{n+1}_{ij+1}\; u^{n+1}_{ij+1}+ \beta^{n+1}_{ij+1}, &
\quad
i=1,N-1,&
\quad
u^{n+1}_{iN} = \phi_1(ih,1),\end{eqnarray} (48)
where,
\begin{eqnarray}
\alpha^{n+1}_{i+1j}= \frac{B_{ij}^{n+1}}{C_{ij}^{n+1}- \alpha^{...
 ...&
\quad
j=1,N-1, &
\quad
\beta^{n+1}_{i0} = \phi_1(ih,0) \nonumber\end{eqnarray}

Equation 34 - is solved by,
\begin{eqnarray}
A_{ij}^{n+\frac{1}{2}}= g_{11}\,(\mathbf{s}^n_{ij}) 
\quad
 C_{...
 ...^{n+1/2}_{ij}
- g_{11}\,(\mathbf{s}^n_{ij})\;\mathbf{S}_{ij}(v^n).\end{eqnarray}
(49)
The solution for a fixed i in the range $1 \le j \le N-1$ is obtained through,
\begin{eqnarray}
v^{n+1}_{ij}= \alpha^{n+1}_{ij+1}\; v^{n+1}_{ij+1}+ \beta^{n+1}_{ij+1}, &
\quad
i=1,N-1,&
\quad
v^{n+1}_{iN} = \phi_2(ih,0),\end{eqnarray} (50)
where,
\begin{eqnarray}
\alpha^{n+1}_{i+1j}= \frac{B_{ij}^{n+1}}{C_{ij}^{n+1}- \alpha^{...
 ...
\quad
j=1,N-1, &
\quad
\beta^{n+1}_{i0} = \phi_1(ih,0). \nonumber\end{eqnarray}
An approximate solution of the equations 19 will be found at some large time TN that satisfies,  
 \begin{displaymath}
\max_{0\le i,j,\le N} \frac{1}{\tau} 
\sqrt{ (u^{n+1}_{ij}-u^n_{ij})^{2} + (v^{n+1}_{ij}-v^n_{ij})^{2}} \le \epsilon.\end{displaymath} (51)


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Next: Step-by-Step Algorithm Up: REFERENCES Previous: REFERENCES
Stanford Exploration Project
4/5/2006