From b60859bebbe6fb8b708cdcd867a7a1f18eb9b638 Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Fri, 12 Sep 2014 19:50:18 +0530
Subject: [PATCH 1/2] make the seed of a MersenneTwister be always a
 Vector{Uint32}

MersenneTwister's constructor making an instance with an Uint32 seed
were removed in commit 4fb4622f5c. But a subsequent call to
srand(r::MersenneTwister, seed) would only accept an Uint32 as a seed,
and would always make r.seed an Uint32; this was not consistent.
---
 base/random.jl | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/base/random.jl b/base/random.jl
index fee039d6fe9db..b845b780eabf6 100644
--- a/base/random.jl
+++ b/base/random.jl
@@ -13,21 +13,14 @@ abstract AbstractRNG
 
 type MersenneTwister <: AbstractRNG
     state::DSFMT_state
-    seed::Union(Uint32,Vector{Uint32})
+    seed::Vector{Uint32}
 
-    function MersenneTwister(seed::Vector{Uint32})
+    function MersenneTwister(seed::Union(Integer,Vector{Uint32}))
         state = DSFMT_state()
-        dsfmt_init_by_array(state, seed)
-        return new(state, seed)
+        return srand(new(state), seed)
     end
 
-    MersenneTwister(seed=0) = MersenneTwister(make_seed(seed))
-end
-
-function srand(r::MersenneTwister, seed) 
-    r.seed = seed
-    dsfmt_init_gen_rand(r.state, seed)
-    return r
+    MersenneTwister() = MersenneTwister(make_seed(0))
 end
 
 ## initialization
@@ -59,11 +52,18 @@ __init__() = srand()
 
 ## srand()
 
-function srand(seed::Vector{Uint32})
-    global RANDOM_SEED = seed
-    dsfmt_gv_init_by_array(seed)
+function srand(seed::Union(Integer, Vector{Uint32}))
+    global RANDOM_SEED = make_seed(seed)
+    dsfmt_gv_init_by_array(RANDOM_SEED)
 end
-srand(n::Integer) = srand(make_seed(n))
+
+function srand(r::MersenneTwister, seed::Union(Integer, Vector{Uint32}))
+    r.seed = make_seed(seed)
+    dsfmt_init_by_array(r.state, r.seed)
+    return r
+end
+
+make_seed(seed::Vector{Uint32}) = seed
 
 function make_seed(n::Integer)
     n < 0 && throw(DomainError())

From 20ef5673551821b111c2c54b049a02fd7ec4992b Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Fri, 12 Sep 2014 20:23:12 +0530
Subject: [PATCH 2/2] make srand behave as the manual pretended

The srand methods working on a MersenneTwister instance did not catch
up with those working on the global RNG. They are now made similar
thanks to the make_seed function, which implements the different
logics.
Also, the manual is more precise on the types of valid seeds.
---
 base/random.jl      | 55 ++++++++++++++++++++++++++-------------------
 doc/stdlib/base.rst |  2 +-
 2 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/base/random.jl b/base/random.jl
index b845b780eabf6..6aa87aa50ff00 100644
--- a/base/random.jl
+++ b/base/random.jl
@@ -20,16 +20,20 @@ type MersenneTwister <: AbstractRNG
         return srand(new(state), seed)
     end
 
-    MersenneTwister() = MersenneTwister(make_seed(0))
+    MersenneTwister() = MersenneTwister(0)
 end
 
 ## initialization
 
-function srand()
+__init__() = srand()
+
+## make_seed()
+
+function make_seed()
 
 @unix_only begin
     try
-        srand("/dev/urandom")
+        return make_seed("/dev/urandom", 4)
     catch
         println(STDERR, "Entropy pool not available to seed RNG; using ad-hoc entropy sources.")
         seed = reinterpret(Uint64, time())
@@ -37,30 +41,15 @@ function srand()
         try
         seed = hash(seed, parseint(Uint64, readall(`ifconfig` |> `sha1sum`)[1:40], 16))
         end
-        srand(seed)
+        return make_seed(seed)
     end
 end
 
 @windows_only begin
     a = zeros(Uint32, 2)
     win32_SystemFunction036!(a)
-    srand(a)
-end
-end
-
-__init__() = srand()
-
-## srand()
-
-function srand(seed::Union(Integer, Vector{Uint32}))
-    global RANDOM_SEED = make_seed(seed)
-    dsfmt_gv_init_by_array(RANDOM_SEED)
+    return make_seed(a)
 end
-
-function srand(r::MersenneTwister, seed::Union(Integer, Vector{Uint32}))
-    r.seed = make_seed(seed)
-    dsfmt_init_by_array(r.state, r.seed)
-    return r
 end
 
 make_seed(seed::Vector{Uint32}) = seed
@@ -77,14 +66,34 @@ function make_seed(n::Integer)
     end
 end
 
-function srand(filename::String, n::Integer)
+function make_seed(filename::String, n::Integer)
     open(filename) do io
         a = Array(Uint32, int(n))
         read!(io, a)
-        srand(a)
+        a
     end
 end
-srand(filename::String) = srand(filename, 4)
+
+## srand()
+
+srand() = srand(make_seed())
+
+srand(r::MersenneTwister) = srand(r, make_seed())
+
+function srand(seed::Union(Integer, Vector{Uint32}))
+    global RANDOM_SEED = make_seed(seed)
+    dsfmt_gv_init_by_array(RANDOM_SEED)
+end
+
+function srand(r::MersenneTwister, seed::Union(Integer, Vector{Uint32}))
+    r.seed = make_seed(seed)
+    dsfmt_init_by_array(r.state, r.seed)
+    return r
+end
+
+srand(filename::String, n::Integer=4) = srand(make_seed(filename, n))
+
+srand(r::MersenneTwister, filename::String, n::Integer=4) = srand(r, make_seed(filename, n))
 
 ## random floating point values
 
diff --git a/doc/stdlib/base.rst b/doc/stdlib/base.rst
index e237f0af810dc..e3b8521fbcb72 100644
--- a/doc/stdlib/base.rst
+++ b/doc/stdlib/base.rst
@@ -3929,7 +3929,7 @@ Random number generation in Julia uses the `Mersenne Twister library <http://www
 
 .. function:: srand([rng], [seed])
 
-   Reseed the random number generator. If a ``seed`` is provided, the RNG will give a reproducible sequence of numbers, otherwise Julia will get entropy from the system. The ``seed`` may be an unsigned integer, a vector of unsigned integers or a filename, in which case the seed is read from a file. If the argument ``rng`` is not provided, the default global RNG is seeded.
+   Reseed the random number generator. If a ``seed`` is provided, the RNG will give a reproducible sequence of numbers, otherwise Julia will get entropy from the system. The ``seed`` may be a non-negative integer, a vector of ``Uint32`` integers or a filename, in which case the seed is read from a file. If the argument ``rng`` is not provided, the default global RNG is seeded.
 
 .. function:: MersenneTwister([seed])