FOLR (3sciport)

Solves a first order linear recurrence

SYNOPSIS

  Call FOLR( n, x, incx, y, incy )

ARGUMENTS

  n               Integer
                  The length of the linear recurrence.

  x               Real vector.
                  An input vector of length n. (x(1) is arbitrary.)

  incx            Integer.
                  The increment between elements of vector x. For contiguous
                  elements, incx = 1.

  y               Real vector.
                  An input-output vector of length n.

  incy            Integer.
                  The increment between elements of vector y. For contiguous
                  elements, incy = 1.

DESCRIPTION

  The subroutine FOLR solves first-order linear recurrences where vector y is
  overwritten by the result vector.  It has the form:

          Y(1) = Y(1)
          DO I = 2,N
             Y(I) = Y(I) - X(I)*Y(I-1)
          ENDDO

  For equations and other information, see Volume 3: UNICOS Math and
  Scientific Library Reference Manual SR-2081 7.0, Cray Research, Inc.