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Polynomial regression. More...
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| Functions | |
| void | pprz_polyfit_float (float *x, float *y, int n, int p, float *c) | 
| Polynomial regression. | |
Polynomial regression.
Definition in file pprz_polyfit_float.h.
Polynomial regression.
Polynomial regression is a form of linear regression in which the relationship between the independent variable x and the dependent variable y is modelled as an nth order polynomial.
Considering the regression model:
![\[
 y_i = a_0 + a_1 x_i + ... + a_p x_i^p + \epsilon_i  (i = 1 ... n)
 \]](form_10.png)
in matrix form
![\[
 y = Xa + \epsilon
 \]](form_11.png)
where
![\[
 X_{ij} = x_i^j (i = 1 ... n; j = 1 ... p)
 \]](form_8.png)
The vector of estimated polynomial regression coefficients using ordinary least squares estimation is
![\[
 a = (X' X)^{-1} X' y
 \]](form_12.png)
http://en.wikipedia.org/wiki/Polynomial_regression http://fr.wikipedia.org/wiki/R%C3%A9gression_polynomiale http://www.arachnoid.com/sage/polynomial.html
| [in] | x | pointer to the input array of independent variable X [n] | 
| [in] | y | pointer to the input array of dependent variable Y [n] | 
| [in] | n | number of input measurments | 
| [in] | p | degree of the output polynomial | 
| [out] | c | pointer to the output array of polynomial coefficients [p] | 
Polynomial regression is a form of linear regression in which the relationship between the independent variable x and the dependent variable y is modelled as an nth order polynomial.
Considering the regression model:
![\[
 y_i = c_0 + c_1 x_i + ... + c_p x_i^p + \epsilon_i  (i = 1 ... n)
 \]](form_6.png)
in matrix form
![\[
 y = X.c + \epsilon
 \]](form_7.png)
where
![\[
 X_{ij} = x_i^j (i = 1 ... n; j = 1 ... p)
 \]](form_8.png)
The vector of estimated polynomial regression coefficients using ordinary least squares estimation is
![\[
 c = (X' X)^{-1} X' y
 \]](form_9.png)
http://en.wikipedia.org/wiki/Polynomial_regression http://fr.wikipedia.org/wiki/R%C3%A9gression_polynomiale http://www.arachnoid.com/sage/polynomial.html
| [in] | x | pointer to the input array of independent variable X [n] | 
| [in] | y | pointer to the input array of dependent variable Y [n] | 
| [in] | n | number of input measurments | 
| [in] | p | degree of the output polynomial | 
| [out] | c | pointer to the output array of polynomial coefficients [p+1] | 
Definition at line 63 of file pprz_polyfit_float.c.
References float_mat_zero(), float_vect_zero(), foo, MAKE_MATRIX_PTR, p, pprz_svd_float(), and pprz_svd_solve_float().
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