MATLAB: What is the right way to put a polynomial into a function

functionpolynomial

I've tried 2 different lines within my code with variations of both, but nothing seems to be working. Any help would be appreciated.

The polynomial to be called is:

c0 +c(1)x1 +c(2)x2+...+c(N)xN

and below are my 2 attempts:

function p = poly_val(c0,c,x)
  p = sum([c0 c] .* (x.^[0:length(c)]));

p = (c0 + polyval(c*(x.^c)));

Best Answer

"the polynomial ... is: c(0) +c(1)x^1 +c(2)x^2+...+c(N)x*N"

y=polyval(fliplr(c),x);

Better would be to define your coefficient array in obverse order as returned by supplied polyfit and used by polyval functions--then you have no need to write a separate function at all...see <polyfit>

Related Solutions

MATLAB: C0 and x are scalars, c – vector, and p – scalar. If c is [ ], then p = c0. If c is a scalar, then p = c0 + c*x . Else, p =

function y = mypolyval(c0,c,x)
if isempty(c)
  y = c0;
else
  y = c0 + power(x, 1:numel(c))*c(:);
end

The case y = c0 + c*x is already covered by the else. And you can use matrix multiplication of a row and a column vector r*c instead of sum(r.*c').

MATLAB: Atan Taylor Polynomial using polyval function.

You are trying to evaluate the polynomial itself in a loop, although the loop as you wrote it will not do what you think.

The requirement was for polyval to evaluate it, NOT you. So you need to build the coefficients of the polynomial, and pass them into polyval. Let it do the work.

Best Answer

Related Solutions

MATLAB: C0 and x are scalars, c – vector, and p – scalar. If c is [ ], then p = c0. If c is a scalar, then p = c0 + c*x . Else, p =

MATLAB: Atan Taylor Polynomial using polyval function.

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