tridiag_inv_unif_by_sums function

Construct inverse of a tridiagonal matrix T_n(a,b,a).

tridiag_inv_unif_by_sums constructs inverse of a regular tridiagonal matrix T_n(a,b,a) with constant entries by a special algorithm using sums of matrix elements.

tridiag_inv_unif_by_sums(n, a, b)

Arguments

• n: an order of given tridiagonal matrix.
• a: a value of tridiagonal matrix elements that are off-diagonal.
• b: a value of tridiagonal matrix diagonal elements.

Returns

The inverse of matrix T_n(a,b,a).

Examples

tridiag_inv_unif_by_sums(5, 1, 4)
tridiag_inv_unif_by_sums(9, 10, -1)