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-rw-r--r--array.c16
-rw-r--r--enum.c17
-rw-r--r--test/ruby/test_array.rb1
-rw-r--r--test/ruby/test_enum.rb1
4 files changed, 24 insertions, 11 deletions
 diff --git a/array.c b/array.cindex b99ab45..0fa3494 100644--- a/array.c+++ b/array.c@@ -5796,14 +5796,17 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary) } if (RB_FLOAT_TYPE_P(e)) {- /* Kahan's compensated summation algorithm */+ /*+ * Kahan-Babuska balancing compensated summation algorithm+ * See http://link.springer.com/article/10.1007/s00607-005-0139-x+ */ double f, c; f = NUM2DBL(v); c = 0.0; goto has_float_value; for (; i < RARRAY_LEN(ary); i++) {- double x, y, t;+ double x, t; e = RARRAY_AREF(ary, i); if (block_given) e = rb_yield(e);@@ -5819,11 +5822,14 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary) else goto not_float; - y = x - c;- t = f + y;- c = (t - f) - y;+ t = f + x;+ if (fabs(f) >= fabs(x))+ c += ((f - t) + x);+ else+ c += ((x - t) + f); f = t; }+ f += c; return DBL2NUM(f); not_float:diff --git a/enum.c b/enum.cindex b328003..5a56dca 100644--- a/enum.c+++ b/enum.c@@ -3644,8 +3644,11 @@ sum_iter(VALUE i, struct enum_sum_memo *memo) } } else if (RB_FLOAT_TYPE_P(v)) {- /* Kahan's compensated summation algorithm */- double x, y, t;+ /*+ * Kahan-Babuska balancing compensated summation algorithm+ * See http://link.springer.com/article/10.1007/s00607-005-0139-x+ */+ double x, t; float_value: if (RB_FLOAT_TYPE_P(i))@@ -3662,9 +3665,11 @@ sum_iter(VALUE i, struct enum_sum_memo *memo) goto some_value; } - y = x - c;- t = f + y;- c = (t - f) - y;+ t = f + x;+ if (fabs(f) >= fabs(x))+ c += ((f - t) + x);+ else+ c += ((x - t) + f); f = t; } else {@@ -3788,7 +3793,7 @@ enum_sum(int argc, VALUE* argv, VALUE obj) rb_block_call(obj, id_each, 0, 0, enum_sum_i, (VALUE)&memo); if (memo.float_value) {- return DBL2NUM(memo.f);+ return DBL2NUM(memo.f + memo.c); } else { if (memo.n != 0)diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rbindex 24a8eae..5ecaaa3 100644--- a/test/ruby/test_array.rb+++ b/test/ruby/test_array.rb@@ -2821,6 +2821,7 @@ class TestArray < Test::Unit::TestCase 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)+ assert_float_equal(small_number, [large_number, small_number, -large_number].sum) assert_equal("abc", ["a", "b", "c"].sum("")) assert_equal([1, [2], 3], [[1], [[2]], [3]].sum([]))diff --git a/test/ruby/test_enum.rb b/test/ruby/test_enum.rbindex 4ff4f88..c70ec7c 100644--- a/test/ruby/test_enum.rb+++ b/test/ruby/test_enum.rb@@ -903,6 +903,7 @@ class TestEnumerable < Test::Unit::TestCase assert_float_equal(large_number+(small_number*10), [large_number, *[small_number]*10].each.sum) assert_float_equal(large_number+(small_number*10), [large_number/1r, *[small_number]*10].each.sum) assert_float_equal(large_number+(small_number*11), [small_number, large_number/1r, *[small_number]*10].each.sum)+ assert_float_equal(small_number, [large_number, small_number, -large_number].each.sum) assert_equal("abc", ["a", "b", "c"].each.sum("")) assert_equal([1, [2], 3], [[1], [[2]], [3]].each.sum([]))