how find unknowns when Tridiagonal matrix is in three dimensional?

hi.
I want to solve a tridiagonal equation system.
form of a tridiagonal equation system is:

a(m)*x(m-1)+b(m)*x(m)+c(m)*x(m+1)=d(m)

that a,b,c are vectors (one dimensioal arrays).

but I have "three dimensional arrays" in input.i,e I have a(i,j,k),b(i,j,k),c(i,j,k).so I have to slove above tridiagonal matrix when m=i or j or k.

for example,when m=i (i=1:nx),index "j" and "k" have a "for-loop" (j=1:ny, k=1:nz).

can anyone help me?How should I act?
please give me a solution or instruction or algorithm in MATLAB?
Should I use from block tridiagonal matrix?how?please help me...

best wishes...

Try this, maybe it help you, some C and MATLAB examples are given:

http://en.wikipedia.org/wiki/Tridiag...trix_algorithm

thanks for your attention.but this is very simple.I know that how solve tridiagonal matrix in one dimensional.this is vey simple.
But I have three dimensional arrays in input!
I want to use from Block tridiagonal matrix algorithms for three dimensional,but I don't know how?