Need to make a nested loop

I'm new at matlab, here's what i need to do. I've got a inner loop used to solve a polynomial at a given x value, But I need to evaluate the polynomial at 100 x-values. I need help making the loop work. here is what i have that does not work.

    i = 1;
    j = 0;
    while j <= 100;
        j = j+1;
        %Loop used to find the solution to the polynomial at given point
        while i <= n;  
            soln(j,i) = P(1,i)*(Xval(j)).^(n-i);
            i = i + 1;
        end

    end
    %soln
    %Eval = sum(soln)

The inner loop (used to solution to the polynomial) does work. I need to run the inner loop 11 times(for a degree 10 polynomial) and the outter loop 100 times (for 100 xvalues). How can I make this work? I suck at matlab.

[per isakson]

Why not for-loops? Your question is it on loops or polynomials?

[Tony Montgomery]

My question is on loops. I need to solve a polynomial to 100 x values. I need those values stored into an array to be compared to the actual solution of the function I was given. My question is, How do i run the inner loop 10 times, for every 100 x values that i need?

Answer 1

[per isakson]

See Polynomials, Curve fitting, roots, partial fraction expansions

Answer 2

[per isakson]

Is this what you try to do? With my variable names

    n = 11;
    P = 1 : n;           %  the simplest data I can think of
    X = ones( 1, 100 );  %  too allow me to check the result
    S = nan( 100, n );
    for ii = 1 : 100
        for jj = 1 : n
            S(ii,jj) = P(1,jj)*(X(ii)).^(n-jj);
        end
    end

    >> S(1,:)
    ans =
         1     2     3     4     5     6     7     8     9    10    11

Answer 3

[Image Analyst]

Why not just polyfit() and not bother with all that mess?

coefficients = polyfit(P, Xval, 10);  % 10 is way too high for a polynomial!

[Tony Montgomery]

I did, but instructor will not accept. Must do it the long way. I found another way around just not very neat. thanks anyway