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Solution 290807

Submitted on 27 Jul 2013 by Claudio Gelmi

Correct

23Size
Leading solution size is 23.
This solution is locked. To view this solution, you need to provide a solution of the same size or smaller.

Test Suite

Test
Code Input and Output
1
Pass
 
%%% first test: fit to a constant
x = [1,2,3,4]';
y = rand(4,1);
f{1} = @(x) ones(size(x));
aref=mean(y);
assert(norm(fit_coefficients(f,x,y)-aref)<1e-6)
[Warning: Function /users/msssystem6/assert.m has the same name as a MATLAB builtin. We suggest you
rename the function to avoid a potential name conflict.]
[> In fit_coefficients at 3
  In verifyCode>evaluateCode at 227
  In verifyCode at 40
  In fevalJSON at 14]
2
Pass
 
%%% second test: fit to a straight line (linear regression)
x = [1,2,3,4,5]' + randn(5,1);
y = [1,2,3,4,5]' + randn(5,1);
f{1} = @(x) ones(size(x));
f{2} = @(x) x;
aref(2) = sum((x-mean(x)).*(y-mean(y)))/sum((x-mean(x)).^2);
aref(1) = mean(y)-aref(2)*mean(x);
assert(norm(fit_coefficients(f,x,y)-aref')<1e-6)
[Warning: Function /users/msssystem6/assert.m has the same name as a MATLAB builtin. We suggest you
rename the function to avoid a potential name conflict.]
[> In fit_coefficients at 3
  In verifyCode>evaluateCode at 227
  In verifyCode at 40
  In fevalJSON at 14]
3
Pass
 
%%% third test: polynomial fit
x = [1:15]' + randn(15,1);
y = -10+0.2*x-0.5*x.^2+0.4*x.^3+0.001*log(abs(x)) + 0.2*randn(15,1);
f{1} = @(x) ones(size(x));
f{2} = @(x) x;
f{3} = @(x) x.^2;
f{4} = @(x) x.^3;
aref = fliplr(polyfit(x,y,3));
assert(norm(fit_coefficients(f,x,y)-aref')<1e-6)
[Warning: Function /users/msssystem6/assert.m has the same name as a MATLAB builtin. We suggest you
rename the function to avoid a potential name conflict.]
[> In fit_coefficients at 3
  In verifyCode>evaluateCode at 227
  In verifyCode at 40
  In fevalJSON at 14]
4
Pass
 
%%% fourth test: non-polynomial fit (yes, we are that crazy)
x = [0:0.1:2*pi]';
y = 0.123 + 0.456*sin(x).*exp(0.1*x);
f{1} = @(x) ones(size(x));
f{2} = @(x) sin(x).*exp(0.1*x);
aref=[0.123 0.456]';
assert(norm(fit_coefficients(f,x,y)-aref)<1e-6)
[Warning: Function /users/msssystem6/assert.m has the same name as a MATLAB builtin. We suggest you
rename the function to avoid a potential name conflict.]
[> In fit_coefficients at 3
  In verifyCode>evaluateCode at 227
  In verifyCode at 40
  In fevalJSON at 14]