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repair asin and acos on complex numbers (though why the old algorithm was wrong is frankly beyond me)

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svn: r11196
This commit is contained in:
Matthew Flatt 2008-08-12 00:42:25 +00:00
parent 717895e087
commit ea8c4b3f38
1 changed files with 20 additions and 16 deletions
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36
src/mzscheme/src/number.c
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@ -1511,6 +1511,7 @@ static Scheme_Object *complex_tan(Scheme_Object *c)
} }
static Scheme_Object *complex_asin(Scheme_Object *c); static Scheme_Object *complex_asin(Scheme_Object *c);
static Scheme_Object *complex_atan(Scheme_Object *c);
static Scheme_Object *complex_asin(Scheme_Object *c) static Scheme_Object *complex_asin(Scheme_Object *c)
{ {
@ -1519,30 +1520,33 @@ static Scheme_Object *complex_asin(Scheme_Object *c)
one_minus_c_sq = scheme_bin_minus(scheme_make_integer(1), one_minus_c_sq = scheme_bin_minus(scheme_make_integer(1),
scheme_bin_mult(c, c)); scheme_bin_mult(c, c));
sqrt_1_minus_c_sq = scheme_sqrt(1, &one_minus_c_sq); sqrt_1_minus_c_sq = scheme_sqrt(1, &one_minus_c_sq);
return scheme_bin_mult(scheme_make_integer(2),
return scheme_bin_mult(scheme_minus_i, complex_atan(scheme_bin_div(c,
un_log(scheme_bin_plus(scheme_bin_mult(c, scheme_plus_i), scheme_bin_plus(scheme_make_integer(1),
sqrt_1_minus_c_sq))); sqrt_1_minus_c_sq))));
} }
static Scheme_Object *complex_acos(Scheme_Object *c); static Scheme_Object *complex_acos(Scheme_Object *c);
static Scheme_Object *complex_acos(Scheme_Object *c) static Scheme_Object *complex_acos(Scheme_Object *c)
{ {
Scheme_Object *one_minus_c_sq, *sqrt_1_minus_c_sq; Scheme_Object *a, *r;
a = complex_asin(c);
one_minus_c_sq = scheme_bin_minus(scheme_make_integer(1), if (scheme_is_zero(_scheme_complex_imaginary_part(c))
scheme_bin_mult(c, c)); && (scheme_bin_gt(_scheme_complex_real_part(c), scheme_make_integer(1))
sqrt_1_minus_c_sq = scheme_sqrt(1, &one_minus_c_sq); || scheme_bin_lt(_scheme_complex_real_part(c), scheme_make_integer(-1)))) {
/* Make sure real part is 0 or pi */
return scheme_bin_mult(scheme_minus_i, if (scheme_is_negative(_scheme_complex_real_part(c)))
un_log(scheme_bin_plus(c, r = scheme_pi;
scheme_bin_mult(scheme_plus_i, else
sqrt_1_minus_c_sq)))); r = scheme_make_integer(0);
return scheme_make_complex(r, scheme_bin_minus(scheme_make_integer(0),
_scheme_complex_imaginary_part(a)));
} else {
return scheme_bin_minus(scheme_half_pi, a);
}
} }
static Scheme_Object *complex_atan(Scheme_Object *c);
static Scheme_Object *complex_atan(Scheme_Object *c) static Scheme_Object *complex_atan(Scheme_Object *c)
{ {
if (scheme_complex_eq(c, scheme_plus_i) || scheme_complex_eq(c, scheme_minus_i)) if (scheme_complex_eq(c, scheme_plus_i) || scheme_complex_eq(c, scheme_minus_i))