polsbt

Substitute Polynomial Variable

SYNOPSIS:

int a, b;
double a[na], b[nb], c[nc];
polsbt( a, na, b, nb, c );

DESCRIPTION:

If a and b are polynomials, and t = a(x), then
c(t) = b(a(x))
is a polynomial found by substituting a(x) for t.

The subroutine call for this is:
polsbt( a, na, b, nb, c );

a, b, c are polynomials of degree na, nb, nc respectively.
The degree of a polynomial cannot exceed a run-time value MAXPOL.
An operation that attempts to use or generate a polynomial of higher degree might produce a result that suffers truncation at degree MAXPOL.
The value of MAXPOL is set by calling the function
polini( MAXPOL );

Each polynomial is represented by an array containing its coefficients, together with a separately declared integer equal to the degree of the polynomial.
The coefficients appear in ascending order; that is,

2 na
a(x) = a[0] + a[1] * x + a[2] * x + ... + a[na] * x .