plot spline in matlab

how can i plot this spline in matlab so i can plot it with other splines/functions?

Answer 1

[Ayush Anand]

Hi,

I understand you want to plot a spline for some data you have. You can do this using the “fnval” function to evaluate the spline function values at certain points and plot the resultant across them. Here is an example of how you could do the same:

% Assuming x and y are vectors of your data points 
x = ...; % x data  
y = ...; % y data  
    
% Create the cubic spline approximation with the specified end conditions 
spline1 = csape(x, [26, y, -1.06581e-14]); 

% Define the range over which you want to plot the spline 
xx = linspace(min(x), max(x), 1000); % 1000 points for a smooth curve 

% Evaluate the spline at the points in xx 
yy = fnval(spline1, xx); 

% Plot the spline 
plot(xx, yy); 
hold on; % Keep the plot open to add more splines or functions 

% Plot other splines or functions here as required 
% ... 

% Add labels and legend as needed 
xlabel('x'); 
ylabel('y'); 
title('Cubic Spline Approximation'); 
legend('spline1'); % Update legend with appropriate names 
hold off; % Release the plot 

You can read more about the “csape” function and the “fnval” function here:

1. https://www.mathworks.com/help/curvefit/construct-cubic-spline-interpolants.html (An example on how to use “csape” function to plot interpolations)
2. https://www.mathworks.com/help/curvefit/fnval.html (Documentation on the “fnval” function)

I hope this helps!