function value = r8poly_value ( n, a, x ) %*****************************************************************************80 % %% R8POLY_VALUE evaluates an R8 polynomial. % % Discussion: % % For sanity's sake, the value of N indicates the NUMBER of % coefficients, or more precisely, the ORDER of the polynomial, % rather than the DEGREE of the polynomial. The two quantities % differ by 1, but cause a great deal of confusion. % % Given N and A, the form of the polynomial is: % % p(x) = a(1) + a(2) * x + ... + a(n-1) * x^(n-2) + a(n) * x^(n-1) % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 09 April 2005 % % Author: % % John Burkardt % % Parameters: % % Input, integer N, the order of the polynomial. % % Input, real A(1:N), the coefficients of the polynomial. % A(1) is the constant term. % % Input, real X, the point at which the polynomial is to be evaluated. % % Output, real VALUE, the value of the polynomial at X. % value = 0.0; for i = n : -1 : 1 value = value * x + a(i); end return end