/* Compute least squares fit of set of data points *//* Fit is of form y = mx + b.  m is slope, b is intercept */double ls_slope(double *xval, double *yval, int cnt);double ls_intercept(double *xval, double *yval, int cnt);typedef enum {LS_AVG, LS_MAX} ls_err_t;/* Determine error (either absolute or average) of least squares fit */double ls_error(double *xval, double *yval, int cnt, ls_err_t etype);