## functions in matrix.i - T

TDsolve

TDsolve(c, d, e, b) or TDsolve(c, d, e, b, which=which) returns the solution to the tridiagonal system: D(1)*x(1) + E(1)*x(2) = B(1) C(1:-1)*x(1:-2) + D(2:-1)*x(2:-1) + E(2:0)*x(3:0) = B(2:-1) C(0)*x(-1) + D(0)*x(0) = B(0) (i.e.- C is the subdiagonal, D the diagonal, and E the superdiagonal; C and E have one fewer element than D, which is the same length as both B and x) B may have additional dimensions, in which case the returned x will have the same additional dimensions. The WHICH dimension of B, and of the returned x is the one of length n which participates in the matrix solve. By default, WHICH=1, so that the equations being solved involve B(,..) and x(+,..). Non-positive WHICH counts from the final dimension (as for the sort and transpose functions), so that WHICH=0 involves B(..,) and x(..,+). The C, D, and E arguments may be either scalars or vectors; they will be broadcast as appropriate. Interpreted function, defined at i0/matrix.i line 36SEE ALSO: LUsolve, QRsolve, SVsolve, SVdec