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-rw-r--r--ChangeLog8
-rw-r--r--ext/bigdecimal/bigdecimal.c10
-rw-r--r--test/bigdecimal/test_bigdecimal.rb14
3 files changed, 27 insertions, 5 deletions
diff --git a/ChangeLog b/ChangeLog
index 908fdf9..a08a2a4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Thu Nov 21 21:36:00 2013 Kenta Murata <mrkn@mrkn.jp>
+
+ * ext/bigdecimal/bigdecimal.c (BigDecimal_sqrt): Fix the precision of
+ the result BigDecimal of sqrt.
+ [Bug #5266] [ruby-dev:44450]
+
+ * test/bigdecimal/test_bigdecimal.rb: add tests for the above changes.
+
Thu Nov 21 18:49:02 2013 Nobuyoshi Nakada <nobu@ruby-lang.org>
* gc.c (vm_xrealloc, vm_xfree): use malloc_usable_size() to obtain old
diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index e82ac38..53efafd 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -1591,10 +1591,10 @@ BigDecimal_sqrt(VALUE self, VALUE nFig)
size_t mx, n;
GUARD_OBJ(a, GetVpValue(self, 1));
- mx = a->Prec *(VpBaseFig() + 1);
+ mx = a->Prec * (VpBaseFig() + 1);
- n = GetPositiveInt(nFig) + VpDblFig() + 1;
- if(mx <= n) mx = n;
+ n = GetPositiveInt(nFig) + VpDblFig() + BASE_FIG;
+ if (mx <= n) mx = n;
GUARD_OBJ(c, VpCreateRbObject(mx, "0"));
VpSqrt(c, a);
return ToValue(c);
@@ -5654,6 +5654,7 @@ VpSqrt(Real *y, Real *x)
n = (SIGNED_VALUE)y->MaxPrec;
if (x->MaxPrec > (size_t)n) n = (ssize_t)x->MaxPrec;
+
/* allocate temporally variables */
f = VpAlloc(y->MaxPrec * (BASE_FIG + 2), "#1");
r = VpAlloc((n + n) * (BASE_FIG + 2), "#1");
@@ -5691,8 +5692,7 @@ VpSqrt(Real *y, Real *x)
if (VpIsZero(f)) goto converge;
VpAddSub(r, f, y, 1); /* r = y + f */
VpAsgn(y, r, 1); /* y = r */
- if (f->exponent <= prec) goto converge;
- } while(++nr < n);
+ } while (++nr < n);
#ifdef BIGDECIMAL_DEBUG
if (gfDebug) {
diff --git a/test/bigdecimal/test_bigdecimal.rb b/test/bigdecimal/test_bigdecimal.rb
index 91eeafc..78ecd8b 100644
--- a/test/bigdecimal/test_bigdecimal.rb
+++ b/test/bigdecimal/test_bigdecimal.rb
@@ -804,6 +804,20 @@ class TestBigDecimal < Test::Unit::TestCase
assert_equal(1, BigDecimal.new("1").sqrt(1))
end
+ def test_sqrt_5266
+ x = BigDecimal('2' + '0'*100)
+ assert_equal('0.14142135623730950488016887242096980785696718753769480731',
+ x.sqrt(56).to_s(56).split(' ')[0])
+ assert_equal('0.1414213562373095048801688724209698078569671875376948073',
+ x.sqrt(55).to_s(55).split(' ')[0])
+
+ x = BigDecimal('2' + '0'*200)
+ assert_equal('0.14142135623730950488016887242096980785696718753769480731766797379907324784621070388503875343276415727350138462',
+ x.sqrt(110).to_s(110).split(' ')[0])
+ assert_equal('0.1414213562373095048801688724209698078569671875376948073176679737990732478462107038850387534327641572735013846',
+ x.sqrt(109).to_s(109).split(' ')[0])
+ end
+
def test_fix
x = BigDecimal.new("1.1")
assert_equal(1, x.fix)