sxx 287 core/gps_math.c rcb->sxx = 0.0; sxx 316 core/gps_math.c rcb->sxx -= old_x*old_x; sxx 327 core/gps_math.c rcb->sxx += x*x; sxx 350 core/gps_math.c det = rcb->n*rcb->sxx - rcb->sx*rcb->sx; sxx 356 core/gps_math.c rcb->t = (rcb->sxx*rcb->sy - rcb->sx * rcb->sxy) / det; sxx 66 core/gps_math.h double sxx;