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// Regression is a class to compute a linear regression
//
// call point(x, y) to add a data point
// call regress() to compute the regression
// call f(x) to evaluate the linear regression at x
// call f_inv(y) to evaluate the inverse linear regression at y
// to restart with new points, call init()
// regress() can be called after each point()
//
// other forms of regression should be added. This one does
// standard least squares regression
class Regression {
float sumxx; // sum of x^2
float sumyy; // sum of y^2
float sumxy; // sum of xy
float sumx; // sum of x
float sumy; // sum of y
int n; // number of points
float a, b; // regression line is a + b*x
public:
Regression();
void init();
void point(float x, float y);
void regress();
float f(float x);
float f_inv(float y);
};
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