/* for large input values use : arctan(x) = (PI / 2) - arctan(1 / |x|) and sign of result = sign of original input */ void M_arctan_large_input(M_APM rr, int places, M_APM xx) { M_APM tmp1, tmp2; tmp1 = M_get_stack_var(); tmp2 = M_get_stack_var(); M_check_PI_places(places); m_apm_divide(tmp1, (places + 6), MM_One, xx); /* 1 / xx */ tmp1->m_apm_sign = 1; /* make positive */ m_apm_arctan(tmp2, (places + 6), tmp1); m_apm_subtract(tmp1, MM_lc_HALF_PI, tmp2); m_apm_round(rr, places, tmp1); rr->m_apm_sign = xx->m_apm_sign; /* fix final sign */ M_restore_stack(2); }
void m_apm_arctan2(M_APM rr, int places, M_APM yy, M_APM xx) { M_APM tmp5, tmp6, tmp7; int ix, iy; iy = yy->m_apm_sign; ix = xx->m_apm_sign; if (ix == 0) /* x == 0 */ { if (iy == 0) /* y == 0 */ { M_apm_log_error_msg(M_APM_RETURN, "\'m_apm_arctan2\', Both Inputs = 0"); M_set_to_zero(rr); return; } M_check_PI_places(places); m_apm_round(rr, places, MM_lc_HALF_PI); rr->m_apm_sign = iy; return; } if (iy == 0) { if (ix == 1) { M_set_to_zero(rr); } else { M_check_PI_places(places); m_apm_round(rr, places, MM_lc_PI); } return; } /* * the special cases have been handled, now do the real work */ tmp5 = M_get_stack_var(); tmp6 = M_get_stack_var(); tmp7 = M_get_stack_var(); m_apm_divide(tmp6, (places + 6), yy, xx); m_apm_arctan(tmp5, (places + 6), tmp6); if (ix == 1) /* 'x' is positive */ { m_apm_round(rr, places, tmp5); } else /* 'x' is negative */ { M_check_PI_places(places); if (iy == 1) /* 'y' is positive */ { m_apm_add(tmp7, tmp5, MM_lc_PI); m_apm_round(rr, places, tmp7); } else /* 'y' is negative */ { m_apm_subtract(tmp7, tmp5, MM_lc_PI); m_apm_round(rr, places, tmp7); } } M_restore_stack(3); }
void m_apm_arctan_mt(M_APM rr, int places, M_APM aa) { m_apm_enter(); m_apm_arctan(rr,places,aa); m_apm_leave(); }