array.c: sum for Rational and Float mixed arrays

* array.c (rb_ary_sum): apply the precision compensated algorithm
  for an array in which Rational and Float values are mixed.

* test/ruby/test_array.rb (test_sum): add assertions for the above
  change.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54601 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
mrkn 2016-04-15 13:33:05 +00:00
parent 4bf8fa83b7
commit a945eb9dda
3 changed files with 28 additions and 0 deletions

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@ -1,3 +1,11 @@
Fri Apr 15 22:31:00 2016 Kenta Murata <mrkn@mrkn.jp>
* array.c (rb_ary_sum): apply the precision compensated algorithm
for an array in which Rational and Float values are mixed.
* test/ruby/test_array.rb (test_sum): add assertions for the above
change.
Fri Apr 15 22:30:01 2016 Nobuyoshi Nakada <nobu@ruby-lang.org>
* thread.c (rb_thread_setname): defer setting native thread name

18
array.c
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@ -5722,6 +5722,8 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
if (RB_FLOAT_TYPE_P(e)) {
/* Kahan's compensated summation algorithm */
double f, c;
float_value:
f = NUM2DBL(v);
c = 0.0;
for (; i < RARRAY_LEN(ary); i++) {
@ -5735,6 +5737,8 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
x = FIX2LONG(e);
else if (RB_TYPE_P(e, T_BIGNUM))
x = rb_big2dbl(e);
else if (RB_TYPE_P(e, T_RATIONAL))
x = rb_num2dbl(e);
else
goto not_float;
@ -5749,6 +5753,20 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
v = DBL2NUM(f);
}
if (RB_TYPE_P(e, T_RATIONAL)) {
for (; i < RARRAY_LEN(ary); i++) {
e = RARRAY_AREF(ary, i);
if (block_given)
e = rb_yield(e);
if (RB_FLOAT_TYPE_P(e)) {
v = rb_to_float(v);
goto float_value;
}
v = rb_funcall(v, idPLUS, 1, e);
}
return v;
}
for (; i < RARRAY_LEN(ary); i++) {
e = RARRAY_AREF(ary, i);
if (block_given)

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@ -2774,6 +2774,8 @@ class TestArray < Test::Unit::TestCase
small_number /= 10
end
assert_float_equal(large_number+(small_number*10), [large_number, *[small_number]*10].sum)
assert_float_equal(large_number+(small_number*10), [large_number/1r, *[small_number]*10].sum)
assert_float_equal(large_number+(small_number*11), [small_number, large_number/1r, *[small_number]*10].sum)
end
private