# Random#rand

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r = Random.new
r.rand #=> a float in 0.0…1.0
r.rand(max_num) #=> a number in 0.0…max_num
r.rand(range) #=> a number in range

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# Index: object.c

— object.c (revision 24648)
+++ object.c (working copy)
@@ -2300,4 +2300,14 @@ rb_to_float(VALUE val)
}

+VALUE
+rb_check_to_float(VALUE val)
+{

• if (TYPE(val) == T_FLOAT) return val;
• if (!rb_obj_is_kind_of(val, rb_cNumeric)) {
• return Qnil;
• }
• return rb_check_convert_type(val, T_FLOAT, “Float”, “to_f”);
+}

# double rb_num2dbl(VALUE val) Index: random.c

— random.c (revision 24648)
+++ random.c (working copy)
@@ -179,4 +179,14 @@ genrand_real(struct MT mt)
return(a
67108864.0+b)(1.0/9007199254740992.0);
}
+
+/
generates a random number on [0,1] with 53-bit resolution*/
+static double int_pair_to_real_inclusive(unsigned int a, unsigned int
b);
+static double
+genrand_real2(struct MT *mt)
+{

• unsigned int a = genrand_int32(mt), b = genrand_int32(mt);
• return int_pair_to_real_inclusive(a, b);
+}

/* These real versions are due to Isaku Wada, 2002/01/09 added */

@@ -239,4 +249,55 @@ rb_genrand_real(void)
#define SIZEOF_INT32 (31/CHAR_BIT + 1)

+static double
+int_pair_to_real_inclusive(unsigned int a, unsigned int b)
+{

• VALUE x = rb_big_new(roomof(64, BITSPERDIG), 1);
• VALUE m = rb_big_new(roomof(53, BITSPERDIG), 1);
• BDIGIT *xd = BDIGITS(x);
• int i = 0;
• double r;
• xd[i++] = (BDIGIT)b;
+#if BITSPERDIG < 32
• xd[i++] = (BDIGIT)(b >> BITSPERDIG);
+#endif
• xd[i++] = (BDIGIT)a;
+#if BITSPERDIG < 32
• xd[i++] = (BDIGIT)(a >> BITSPERDIG);
+#endif
• xd = BDIGITS(m);
+#if BITSPERDIG < 53
• MEMZERO(xd, BDIGIT, roomof(53, BITSPERDIG) - 1);
+#endif
• xd[53 / BITSPERDIG] = 1 << 53 % BITSPERDIG;
• xd[0] |= 1;
• x = rb_big_mul(x, m);
• if (FIXNUM_P(x)) {
+#if CHAR_BIT * SIZEOF_LONG > 64
• r = (double)(FIX2ULONG(x) >> 64);
+#else
• return 0.0;
+#endif
• }
• else {
+#if 64 % BITSPERDIG == 0
• long len = RBIGNUM_LEN(x);
• xd = BDIGITS(x);
• MEMMOVE(xd, xd + 64 / BITSPERDIG, BDIGIT, len - 64 / BITSPERDIG);
• MEMZERO(xd + len - 64 / BITSPERDIG, BDIGIT, 64 / BITSPERDIG);
• r = rb_big2dbl(x);
+#else
• x = rb_big_rshift(x, INT2FIX(64));
• if (FIXNUM_P(x)) {
• `````` r = (double)FIX2ULONG(x);
``````
• }
• else {
• `````` r = rb_big2dbl(x);
``````
• }
+#endif
• }
• return ldexp(r, -53);
+}

VALUE rb_cRandom;
#define id_minus ‘-’
@@ -830,17 +891,12 @@ rb_random_bytes(VALUE obj, long n)

static VALUE
-range_values(VALUE vmax, VALUE *begp)
+range_values(VALUE vmax, VALUE *begp, int *exclp)
{

• VALUE end, r, one = INT2FIX(1);
• int excl;
• VALUE end, r;
• if (!rb_range_values(vmax, begp, &end, &excl)) return Qfalse;
• if (!rb_range_values(vmax, begp, &end, exclp)) return Qfalse;
if (!rb_respond_to(end, id_minus)) return Qfalse;
r = rb_funcall2(end, id_minus, 1, begp);
if (NIL_P®) return Qfalse;
• if (!excl && rb_respond_to(r, id_plus)) {
• r = rb_funcall2(r, id_plus, 1, &one);
• if (NIL_P®) return Qfalse;
• }
return r;
}
@@ -854,5 +910,5 @@ add_to_begin(VALUE beg, VALUE offset)

static VALUE
-rand_int(struct MT *mt, VALUE vmax)
+rand_int(struct MT *mt, VALUE vmax, int restrictive)
{
long max;
@@ -862,5 +918,12 @@ rand_int(struct MT *mt, VALUE vmax)
max = FIX2LONG(vmax);
if (!max) return Qnil;

• r = limited_rand(mt, (unsigned long)(max < 0 ? -max : max) - 1);
• if (max < 0) {
• `````` if (restrictive) return Qnil;
``````
• `````` max = -max;
``````
• }
• else if (max == 1 && restrictive) {
• `````` return Qnil;
``````
• }
• r = limited_rand(mt, (unsigned long)max - 1);
return ULONG2NUM®;
}
@@ -869,4 +932,5 @@ rand_int(struct MT *mt, VALUE vmax)
if (rb_bigzero_p(vmax)) return Qnil;
if (!RBIGNUM_SIGN(vmax)) {
• `````` if (restrictive) return Qnil;
vmax = rb_big_clone(vmax);
RBIGNUM_SET_SIGN(vmax, 1);
``````

@@ -876,4 +940,5 @@ rand_int(struct MT *mt, VALUE vmax)
max = FIX2LONG(vmax);
if (max == -1) return Qnil;

• `````` if (max == 0 && restrictive) return Qnil;
r = limited_rand(mt, max);
return LONG2NUM(r);
``````

@@ -885,6 +950,19 @@ rand_int(struct MT *mt, VALUE vmax)
}

+static inline double
+float_value(VALUE v)
+{

• double x = RFLOAT_VALUE(v);
• if (isinf(x) || isnan(x)) {
• VALUE error = INT2FIX(EDOM);
• rb_exc_raise(rb_class_new_instance(1, &error, rb_eSystemCallError));
• }
• return x;
+}

/*

• call-seq: prng.int(limit) -> integer
• call-seq:
• ``````prng.rand -> float
``````
• ``````prng.rand(limit) -> number
``````
• When the argument is an +Integer+ or a +Bignum+, it returns a
@@ -893,8 +971,13 @@ rand_int(struct MT *mt, VALUE vmax)
• integer or zero, it raises an ArgumentError.
• When the argument is a +Float+, it returns a random floating point
• number between 0.0 and max, including 0.0 and excluding max.
• When the argument limit is a +Range+, it returns a random
• integer from integers where range.member?(integer) == true.
• ``````prng.int(5..9)  # => one of [5, 6, 7, 8, 9]
``````
• ``````prng.int(5...9) # => one of [5, 6, 7, 8]
``````
• number where range.member?(number) == true.
• ``````prng.rand(5..9)  # => one of [5, 6, 7, 8, 9]
``````
• ``````prng.rand(5...9) # => one of [5, 6, 7, 8]
``````
• ``````prng.rand(5.0..9.0) # => between 5.0 and 9.0, including 9.0
``````
• ``````prng.rand(5.0...9.0) # => between 5.0 and 9.0, excluding 9.0
``````
• +begin+/+end+ of the range have to have subtruct and add methods.
@@ -902,67 +985,71 @@ rand_int(struct MT *mt, VALUE vmax)
• Otherwise, it raises an ArgumentError.
*/
-VALUE
-rb_random_int(VALUE obj, VALUE vmax)
-{
• VALUE v, beg = Qundef;
• rb_random_t *rnd = get_rnd(obj);
• v = rb_check_to_integer(vmax, “to_int”);
• if (NIL_P(v)) {
• /* range like object support */
• if (!(v = range_values(vmax, &beg))) {
• `````` v = vmax;
``````
• }
• v = rb_to_int(v);
• beg = rb_to_int(beg);
• }
• v = rand_int(&rnd->mt, v);
• if (NIL_P(v)) v = INT2FIX(0);
-}

## -#define random_int rb_random_int

-/*

• call-seq:
• ``````prng.float -> float
``````
• ``````prng.float([max=1.0]) -> float
``````
• Returns a random floating point number between 0.0 and max,
• including 0.0 and excluding max.
• */
static VALUE
-random_float(int argc, VALUE *argv, VALUE obj)
+random_rand(int argc, VALUE *argv, VALUE obj)
{
• VALUE rb_check_to_float(VALUE);
rb_random_t *rnd = get_rnd(obj);
• VALUE vmax, beg = Qundef;
• double max = 0, r;
• VALUE vmax, beg = Qundef, v;
• int excl = 0;
• switch (argc) {
• `````` case 0:
``````
• break;
• `````` case 1:
``````
• vmax = argv[0];
• if (TYPE(vmax) == T_FLOAT ||
• `````` !NIL_P(vmax = rb_to_float(vmax)) ||
``````
• `````` (vmax = range_values(vmax, &beg)) != Qfalse) {
``````
• `````` max = RFLOAT_VALUE(vmax);
``````
• `````` if (isinf(max) || isnan(max)) {
``````
• VALUE error = INT2FIX(EDOM);
• rb_exc_raise(rb_class_new_instance(1, &error,
rb_eSystemCallError));
• if (argc == 0) {
• `````` zero_arg:
``````
• return rb_float_new(genrand_real(&rnd->mt));
• }
• else if (argc != 1) {
• rb_raise(rb_eArgError, “wrong number of arguments (%d for 0…1)”,
argc);
• }
• vmax = argv[0];
• if (NIL_P(vmax)) {
• goto zero_arg;
• }
• else if (TYPE(vmax) != T_FLOAT && (v = rb_check_to_integer(vmax,
“to_int”), !NIL_P(v))) {
• v = rand_int(&rnd->mt, vmax = v, 1);
• }
• else if (v = rb_check_to_float(vmax), !NIL_P(v)) {
• double max = float_value(v);
• v = rb_float_new(max * genrand_real(&rnd->mt));
• }
• else if ((v = range_values(vmax, &beg, &excl)) != Qfalse) {
• vmax = v;
• if (TYPE(vmax) != T_FLOAT && (v = rb_check_to_integer(vmax,
“to_int”), !NIL_P(v))) {
• `````` long max;
``````
• `````` vmax = v;
``````
• `````` v = Qnil;
``````
• `````` if (FIXNUM_P(vmax)) {
``````
• ``````   fixnum:
``````
• if ((max = FIX2LONG(vmax) - excl) > 0) {
• ``````   unsigned long r = limited_rand(&rnd->mt, (unsigned long)max);
``````
• ``````   v = ULONG2NUM(r);
``````
• }
• `````` }
``````
• `````` else if (BUILTIN_TYPE(vmax) == T_BIGNUM && RBIGNUM_SIGN(vmax) &&
``````

!rb_bigzero_p(vmax)) {

• vmax = excl ? rb_big_minus(vmax, INT2FIX(1)) : rb_big_norm(vmax);
• if (FIXNUM_P(vmax)) {
• ``````   excl = 0;
``````
• ``````   goto fixnum;
``````
• }
• v = limited_big_rand(&rnd->mt, RBIGNUM(vmax));
}
}
• else {
• `````` beg = Qundef;
``````
• `````` Check_Type(argv[0], T_FLOAT);
``````
• else if (v = rb_check_to_float(vmax), !NIL_P(v)) {
• `````` double max = float_value(v), r;
``````
• `````` v = Qnil;
``````
• `````` if (max > 0.0) {
``````
• if (excl) {
• ``````   r = genrand_real(&rnd->mt);
``````
• }
• else {
• ``````   r = genrand_real2(&rnd->mt);
``````
• }
• v = rb_float_new(r * max);
• `````` }
``````
}
• break;
• `````` default:
``````
• rb_scan_args(argc, argv, “01”, 0);
• break;
}
• r = genrand_real(&rnd->mt);
• if (argc) r *= max;
• else {
• NUM2LONG(vmax);
• }
• if (NIL_P(v)) rb_raise(rb_eArgError, “invalid argument”);
}

@@ -1020,5 +1107,5 @@ rb_f_rand(int argc, VALUE *argv, VALUE o
if (NIL_P(vmax)) goto zero_arg;
vmax = rb_to_int(vmax);

• if (vmax == INT2FIX(0) || NIL_P(r = rand_int(mt, vmax))) {
• if (vmax == INT2FIX(0) || NIL_P(r = rand_int(mt, vmax, 0))) {
zero_arg:
return DBL2NUM(genrand_real(mt));
@@ -1059,7 +1146,6 @@ Init_Random(void)
rb_define_alloc_func(rb_cRandom, random_alloc);
rb_define_method(rb_cRandom, “initialize”, random_init, -1);
• rb_define_method(rb_cRandom, “int”, random_int, 1);
• rb_define_method(rb_cRandom, “rand”, random_rand, -1);
rb_define_method(rb_cRandom, “bytes”, random_bytes, 1);
• rb_define_method(rb_cRandom, “float”, random_float, -1);
rb_define_method(rb_cRandom, “seed”, random_get_seed, 0);
rb_define_method(rb_cRandom, “initialize_copy”, random_copy, 1);
Index: test/ruby/test_rand.rb
===================================================================
— test/ruby/test_rand.rb (revision 24648)
+++ test/ruby/test_rand.rb (working copy)
@@ -11,12 +11,12 @@ class TestRand < Test::Unit::TestCase
assert_equal(w, rand(m))
rnds.each do |rnd|
• ``````   assert_equal(w, rnd.int(m))
``````
• ``````   assert_equal(w, rnd.rand(m))
end
rnds2.each do |rnd|
``````
• ``````   r=rnd.int(i...(m+i))
``````
• ``````   r=rnd.rand(i...(m+i))
assert_equal(w+i, r)
end
rnds3.each do |rnd|
``````
• ``````   r=rnd.int(i..(m+i-1))
``````
• ``````   r=rnd.rand(i..(m+i-1))
assert_equal(w+i, r)
end
``````

@@ -111,14 +111,12 @@ class TestRand < Test::Unit::TestCase
end

• def test_neg_0x10000000000
• def test_0x10000000000
ws = %w(455570294424 1073054410371 790795084744 2445173525
1088503892627)
assert_random_int(ws, 0x10000000000, 3)
• assert_random_int(ws, -0x10000000000, 3)
end

• def test_neg_0x10000

• def test_0x10000
ws = %w(2732 43567 42613 52416 45891)
assert_random_int(ws, 0x10000)
• assert_random_int(ws, -0x10000)
end

@@ -127,17 +125,16 @@ class TestRand < Test::Unit::TestCase
rnd = Random.new(0)
assert_equal(44, rand(100.0))

• assert_equal(44, rnd.int(100.0))
• assert_equal(44, rnd.rand(100))
assert_equal(1245085576965981900420779258691, rand((2**100).to_f))
• assert_equal(1245085576965981900420779258691,
rnd.int((2**100).to_f))
• assert_equal(1245085576965981900420779258691, rnd.rand(2100))
assert_equal(914679880601515615685077935113, rand(-(2
100).to_f))
• assert_equal(914679880601515615685077935113,
rnd.int(-(2**100).to_f))

srand(0)
rnd = Random.new(0)
assert_equal(997707939797331598305742933184, rand(2**100))

• assert_equal(997707939797331598305742933184, rnd.int(2**100))

• assert_equal(997707939797331598305742933184, rnd.rand(2100))
assert_in_delta(0.602763376071644, rand((2
100).coerce(0).first),
0.000000000000001)
• assert_equal(0, rnd.int((2**100).coerce(0).first))
• assert_raise(ArgumentError) {rnd.rand((2**100).coerce(0).first)}

srand(0)
@@ -145,5 +142,5 @@ class TestRand < Test::Unit::TestCase
assert_in_delta(0.548813503927325, rand(nil),
0.000000000000001)

• assert_in_delta(0.548813503927325, rnd.float(),
• assert_in_delta(0.548813503927325, rnd.rand(),
0.000000000000001)
srand(0)
@@ -152,9 +149,9 @@ class TestRand < Test::Unit::TestCase
def o.to_int; 100; end
assert_equal(44, rand(o))
• assert_equal(44, rnd.int(o))
• assert_equal(44, rnd.rand(o))
assert_equal(47, rand(o))
• assert_equal(47, rnd.int(o))
• assert_equal(47, rnd.rand(o))
assert_equal(64, rand(o))
• assert_equal(64, rnd.int(o))
• assert_equal(64, rnd.rand(o))
end

@@ -162,5 +159,5 @@ class TestRand < Test::Unit::TestCase
srand
assert_kind_of(Integer, rand(2))

• assert_kind_of(Integer, Random.new.int(2))
• assert_kind_of(Integer, Random.new.rand(2))

srand(2**100)
@@ -168,5 +165,5 @@ class TestRand < Test::Unit::TestCase
%w(3258412053).each {|w|
assert_equal(w.to_i, rand(0x100000000))

• `````` assert_equal(w.to_i, rnd.int(0x100000000))
``````
• `````` assert_equal(w.to_i, rnd.rand(0x100000000))
``````
}
end
@@ -184,9 +181,9 @@ class TestRand < Test::Unit::TestCase
r = Random.new(0)
%w(2357136044 2546248239 3071714933).each do |w|
• `````` assert_equal(w.to_i, r.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r.rand(0x100000000))
``````
end
GC.start
%w(3626093760 2588848963 3684848379).each do |w|
• `````` assert_equal(w.to_i, r.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r.rand(0x100000000))
``````
end
end
@@ -194,9 +191,9 @@ class TestRand < Test::Unit::TestCase
def test_random_type_error
assert_raise(TypeError) { Random.new(Object.new) }
• assert_raise(TypeError) { Random.new(0).int(Object.new) }
• assert_raise(TypeError) { Random.new(0).rand(Object.new) }
end

def test_random_argument_error

• assert_raise(ArgumentError) { Random.new(0).float(0, 0) }
• assert_raise(ArgumentError) { Random.new(0).rand(0, 0) }
end

@@ -211,15 +208,15 @@ class TestRand < Test::Unit::TestCase
r2 = r1.dup
%w(2357136044 2546248239 3071714933).each do |w|

• `````` assert_equal(w.to_i, r1.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r1.rand(0x100000000))
``````
end
%w(2357136044 2546248239 3071714933).each do |w|
• `````` assert_equal(w.to_i, r2.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r2.rand(0x100000000))
``````
end
r2 = r1.dup
%w(3626093760 2588848963 3684848379).each do |w|
• `````` assert_equal(w.to_i, r1.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r1.rand(0x100000000))
``````
end
%w(3626093760 2588848963 3684848379).each do |w|
• `````` assert_equal(w.to_i, r2.int(0x100000000))
``````
• `````` assert_equal(w.to_i, r2.rand(0x100000000))
``````
end
end
@@ -310,5 +307,5 @@ END
assert_equal(state, r.instance_eval { state })
assert_equal(state, Random.instance_eval { state })
• r.int(0x100)
• r.rand(0x100)
assert_equal(state, r.instance_eval { state })
end
@@ -317,7 +314,7 @@ END
r = Random.new(0)
assert_equal(1, r.instance_eval { left })
• r.int(0x100)
• r.rand(0x100)
assert_equal(624, r.instance_eval { left })
• r.int(0x100)
• r.rand(0x100)
assert_equal(623, r.instance_eval { left })
srand(0)
@@ -338,27 +335,26 @@ END
def test_random_range
r = Random.new(0)
• %w(9 5 8).each {|w| assert_equal(w.to_i, r.int(5…9)) }
• %w(-237 731 383).each {|w| assert_equal(w.to_i, r.int(-1000…1000))
}
• %w(9 5 8).each {|w| assert_equal(w.to_i, r.rand(5…9)) }
• %w(-237 731 383).each {|w| assert_equal(w.to_i,
r.rand(-1000…1000)) }
%w(1267650600228229401496703205382
1267650600228229401496703205384
1267650600228229401496703205383).each do |w|
• `````` assert_equal(w.to_i, r.int(2**100+5..2**100+9))
``````
• `````` assert_equal(w.to_i, r.rand(2**100+5..2**100+9))
``````
end
• assert_equal(3, r.int(3.1…4), ‘[ruby-core:24679]’)
• v = r.rand(3.1…4)
• assert_instance_of(Float, v, ‘[ruby-core:24679]’)
• assert_includes(3.1…4, v)
end

def test_random_float
r = Random.new(0)

• assert_in_delta(0.5488135039273248, r.float, 0.0001)
• assert_in_delta(0.7151893663724195, r.float, 0.0001)
• assert_in_delta(0.6027633760716439, r.float, 0.0001)
• assert_in_delta(1.0897663659937937, r.float(2), 0.0001)
• assert_in_delta(5.3704626067153264e+29, r.float(2100), 1025)
• assert_in_delta(0.5488135039273248, r.rand, 0.0001)
• assert_in_delta(0.7151893663724195, r.rand, 0.0001)
• assert_in_delta(0.6027633760716439, r.rand, 0.0001)
• assert_in_delta(1.0897663659937937, r.rand(2.0), 0.0001)
• assert_in_delta(5.3704626067153264e+29, r.rand((2100).to_f),
10
25)
• assert_raise(Errno::EDOM, Errno::ERANGE) { r.float(1.0 / 0.0) }
• assert_raise(Errno::EDOM, Errno::ERANGE) { r.float(0.0 / 0.0) }
• # is this intentional?

• assert_raise(TypeError) { r.float(1…2) }
• assert_raise(Errno::EDOM, Errno::ERANGE) { r.rand(1.0 / 0.0) }
• assert_raise(Errno::EDOM, Errno::ERANGE) { r.rand(0.0 / 0.0) }
end

@@ -369,7 +365,7 @@ END
r1 = r.dup
r2 = r.dup

• r1.int(0x100)
• r1.rand(0x100)
assert(r1 != r2)
• r2.int(0x100)
• r2.rand(0x100)
assert(r1 == r2)
end

e\$B\$^\$D\$b\$He(B e\$B\$f\$-\$R\$m\$G\$9e(B

In message “Re: [ruby-dev:39158] Random#rand”
on Tue, 25 Aug 2009 18:23:11 +0900, Nobuyoshi N.
[email protected] writes:

|e\$B:#\$Ne(Btrunke\$B\$K\$O!“;n83E*\$Ke(BRandome\$B%/%i%9\$,\$”\$j\$^\$9!#\$3\$l\$K\$Oe(Binte\$B\$He(B
|floate\$B\$H\$\$\$&%a%=%C%I\$,\$"\$j\$^\$9\$,!"e(BKernel#rande\$B\$H\$N8_49@-\$K7g\$1\$F\$\$e(B
|e\$B\$?\$j!“e(BRangee\$B\$KBP\$9\$kF0:n\$,\$o\$+\$j\$K\$/\$+\$C\$?\$j\$7\$^\$9!#\$=\$3\$Ge(B
|Random#rande\$B\$KE}9g\$7\$?\$\$\$H;W\$&\$N\$G\$9\$,!”\$\$\$+\$,\$G\$7\$g\$&\$+!#e(B

e\$B\$\$\$\$\$s\$8\$c\$J\$\$\$G\$7\$g\$&\$+!#E}9g\$9\$k\$H8@\$&\$3\$H\$Oe(Binte\$B\$He(Bfloate\$B\$O:oe(B
e\$B=|\$H\$\$\$&\$3\$H\$G\$7\$g\$&\$+!#e(B

e\$B@>;3OB9-\$G\$9!#e(B

At Tue, 25 Aug 2009 18:23:11 +0900,

r = Random.new
r.rand #=> a float in 0.0…1.0
r.rand(max_num) #=> a number in 0.0…max_num
r.rand(range) #=> a number in range

e\$B0z?t\$,M?\$(\$i\$l\$?>l9g\$O7k2L\$N%/%i%9\$O0z?t\$N%/%i%9\$K=>\$\$\$^\$9!#e(B
Rangee\$B\$N>l9g\$ON>C<\$NCM\$N:9\$r;H\$\$\$^\$9!#e(B

Random#rand(1) e\$B\$He(B Random#rand(0…1)
e\$B\$N5sF0\$,0c\$&\$N\$O0U?^\$7\$?5sF0\$G\$7\$g\$&\$+e(B?
e\$B%(%i!<%a%C%;!<%8\$,!Ve(Binvalid
argumente\$B!W\$@\$1\$J\$N\$b\$o\$+\$j\$K\$/\$\$\$h\$&\$Ke(B
e\$B;W\$\$\$^\$9!#e(B

% ruby-trunk -e ‘p Random.new.rand(1)’
0
% ruby-trunk -e ‘p Random.new.rand(0…1)’
-e:1:in `rand': invalid argument (ArgumentError) from -e:1:in`
%

e\$B0J2<\$N\$h\$&\$KJQ99\$9\$k\$HF1\$85sF0\$K\$J\$j\$^\$7\$?!#e(B

diff --git a/random.c b/random.c
index 3b5729f…9bd2c48 100644
— a/random.c
+++ b/random.c
@@ -1016,7 +1016,7 @@ random_rand(int argc, VALUE *argv, VALUE obj)
v = Qnil;
if (FIXNUM_P(vmax)) {
fixnum:

• if ((max = FIX2LONG(vmax) - excl) > 0) {
• if ((max = FIX2LONG(vmax) - excl) >= 0) {
unsigned long r = limited_rand(&rnd->mt, (unsigned long)max);
v = ULONG2NUM®;
}