Lagrange Interpolation related problem (plotting a graph)

x = input('Enter values of x: ');
y = input('Enter values of y: ');
n = length(x);
L = zeros(n,n);
for i = 1:n
    V= 1;
    for j = 1:n
        if i~= j
            V = conv(V,poly(x(j)))/(x(i) - x(j));
        end
    end
    L(i,:) = V*y(i);    
end
L
P = sum(L)

Now here I want to plot the graph of a certain method, But don't know how to do it!

Answer 1

[Sulaymon Eshkabilov]

Hi

The answer is simple:

plot(x, L(1,:)) OR plot(x, L(2,:))

plot(x, V) or plot(x, P)

Or within the loop:

...
if i~= j
            V = conv(V,poly(x(j)))/(x(i) - x(j));
        end
    end
    L(i,:) = V*y(i);   
    plot(x, L(i,:)), hold all
end

[Maha Aftab]

Error using gobjects (line 42)

Not enough input arguments.

Error in newplot (line 47)

fig = gobjects(0);

Error in Untitled3 (line 13)

plot(x, L(i,:)), hold all

This error is shown!!

[Sulaymon Eshkabilov]

The number of values entered for x and y are equal or not?

Make sure that they have equal number of value entries via input().

[Maha Aftab]

They are

[Sulaymon Eshkabilov]

Test again:

x = input('Enter values of x: ');
y = input('Enter values of y: ');
n = length(x);
L = zeros(n,n);
for i = 1:n
    V= 1;
    for j = 1:n
        if i~= j
            V = conv(V,poly(x(j)))/(x(i) - x(j));
        end
    end
    L(i,:) = V*y(i);   
    plot(x, L(i,:)), hold all
end

x = linspace(0, 5);

y = linspace(0, 5)*2+linspace(0, 5).^2;