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math.c: Complex sqrt

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* math.c (rb_math_sqrt): [EXPERIMENTAL] move Complex sqrt support
  from mathn.rb.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55646 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
nobu 2016-07-12 14:13:46 +00:00
parent 89ed4f41a3
commit 745a2aac69
5 changed files with 45 additions and 22 deletions
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5
ChangeLog
View file

@ -1,3 +1,8 @@
Tue Jul 12 23:13:43 2016 Nobuyoshi Nakada <nobu@ruby-lang.org>
* math.c (rb_math_sqrt): [EXPERIMENTAL] move Complex sqrt support
from mathn.rb.
Tue Jul 12 21:59:40 2016 Martin Duerst <duerst@it.aoyama.ac.jp>
* revert r55642 (previous commit) because of test failure at

34
complex.c
View file

@ -535,6 +535,21 @@ m_sin(VALUE x)
#if 0
imp1(sqrt)
VALUE
rb_complex_sqrt(VALUE x)
{
int pos;
VALUE a, re, im;
get_dat1(x);
pos = f_positive_p(dat->imag);
a = f_abs(x);
re = m_sqrt_bang(f_div(f_add(a, dat->real), TWO));
im = m_sqrt_bang(f_div(f_sub(a, dat->real), TWO));
if (!pos) im = f_negate(im);
return f_complex_new2(rb_cComplex, re, im);
}
static VALUE
m_sqrt(VALUE x)
{
@ -543,18 +558,7 @@ m_sqrt(VALUE x)
return m_sqrt_bang(x);
return f_complex_new2(rb_cComplex, ZERO, m_sqrt_bang(f_negate(x)));
}
else {
get_dat1(x);
if (f_negative_p(dat->imag))
return f_conj(m_sqrt(f_conj(x)));
else {
VALUE a = f_abs(x);
return f_complex_new2(rb_cComplex,
m_sqrt_bang(f_div(f_add(a, dat->real), TWO)),
m_sqrt_bang(f_div(f_sub(a, dat->real), TWO)));
}
}
return rb_complex_sqrt(x);
}
#endif
@ -1415,6 +1419,12 @@ rb_complex_set_imag(VALUE cmp, VALUE i)
return cmp;
}
VALUE
rb_complex_abs(VALUE cmp)
{
return nucomp_abs(cmp);
}
/*
* call-seq:
* cmp.to_i -> integer

4
internal.h
View file

@ -903,6 +903,8 @@ VALUE rb_insns_name_array(void);
/* complex.c */
VALUE rb_complex_plus(VALUE, VALUE);
VALUE rb_complex_mul(VALUE, VALUE);
VALUE rb_complex_abs(VALUE x);
VALUE rb_complex_sqrt(VALUE x);
/* cont.c */
VALUE rb_obj_is_fiber(VALUE);
@ -1083,9 +1085,7 @@ VALUE rb_math_hypot(VALUE, VALUE);
VALUE rb_math_log(int argc, const VALUE *argv);
VALUE rb_math_sin(VALUE);
VALUE rb_math_sinh(VALUE);
#if 0
VALUE rb_math_sqrt(VALUE);
#endif
/* newline.c */
void Init_newline(void);

9
lib/mathn.rb
View file

@ -103,14 +103,7 @@ module Math
def sqrt(a)
if a.kind_of?(Complex)
abs = sqrt(a.real*a.real + a.imag*a.imag)
x = sqrt((a.real + abs)/Rational(2))
y = sqrt((-a.real + abs)/Rational(2))
if a.imag >= 0
Complex(x, y)
else
Complex(x, -y)
end
sqrt!(a)
elsif a.respond_to?(:nan?) and a.nan?
a
elsif a >= 0

15
math.c
View file

@ -587,9 +587,24 @@ math_log10(VALUE obj, VALUE x)
static VALUE
math_sqrt(VALUE obj, VALUE x)
{
return rb_math_sqrt(x);
}
VALUE
rb_math_sqrt(VALUE x)
{
double d;
if (RB_TYPE_P(x, T_COMPLEX)) {
int neg = signbit(RCOMPLEX(x)->imag);
double re = Get_Double(RCOMPLEX(x)->real), im;
d = Get_Double(rb_complex_abs(x));
im = sqrt((d - re) / 2.0);
re = sqrt((d + re) / 2.0);
if (neg) im = -im;
return rb_complex_new(DBL2NUM(re), DBL2NUM(im));
}
d = Get_Double(x);
/* check for domain error */
if (d < 0.0) domain_error("sqrt");