MATLAB: Spline and interpolation

curveinterpolationspline

(I'm very new to programming). I want my code to give me the consumption for every speed. So when I for example write consumption(40) in the command window it gives me the consumption for when the speed is 40 km/h.
This is my code so far:
function c = consumption(v)
load roadster.mat;
x = 2:2:200;
y = consumption_Whpkm;
xx=2:200;
pp=spline(x,y,xx);
plot(xx,spline(x,y,xx),'k-',x,y,'ro')
end

Best Answer

You are not using input variable v and assigning a value to output variable c inside the function body. From the context of your question, the correct function definition is

function c = consumption(v)
  load roadster.mat;
  x = 2:2:200;
  y = consumption_Whpkm;
  xx=2:200;
  pp=spline(x,y);
  plot(xx, ppval(pp, xx),'k-',x,y,'ro');
  c = ppval(pp, v);  % assigning value to output for input v
end
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