forked from Mirrorlandia_minetest/minetest
Add API for restoring PseudoRandom and PcgRandom state (#14123)
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@ -30,6 +30,7 @@ core.features = {
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sound_params_start_time = true,
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physics_overrides_v2 = true,
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hud_def_type_field = true,
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random_state_restore = true,
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}
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function core.has_feature(arg)
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@ -5284,6 +5284,10 @@ Utilities
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physics_overrides_v2 = true,
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-- In HUD definitions the field `type` is used and `hud_elem_type` is deprecated (5.9.0)
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hud_def_type_field = true,
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-- PseudoRandom and PcgRandom state is restorable
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-- PseudoRandom has get_state method
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-- PcgRandom has get_state and set_state methods (5.9.0)
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random_state_restore = true,
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}
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```
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@ -8056,7 +8060,7 @@ child will follow movement and rotation of that bone.
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* `get_lighting()`: returns the current state of lighting for the player.
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* Result is a table with the same fields as `light_definition` in `set_lighting`.
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* `respawn()`: Respawns the player using the same mechanism as the death screen,
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including calling on_respawnplayer callbacks.
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including calling `on_respawnplayer` callbacks.
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`PcgRandom`
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-----------
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@ -8079,6 +8083,8 @@ offering very strong randomness.
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* `mean = (max - min) / 2`, and
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* `variance = (((max - min + 1) ^ 2) - 1) / (12 * num_trials)`
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* Increasing `num_trials` improves accuracy of the approximation
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* `get_state()`: return generator state encoded in string
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* `set_state(state_string)`: restore generator state from encoded string
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`PerlinNoise`
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-------------
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@ -8171,6 +8177,8 @@ Uses a well-known LCG algorithm introduced by K&R.
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* `next(min, max)`: return next integer random number [`min`...`max`]
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* Either `max - min == 32767` or `max - min <= 6553` must be true
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due to the simple implementation making a bad distribution otherwise.
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* `get_state()`: return state of pseudorandom generator as number
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* use returned number as seed in PseudoRandom constructor to restore
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`Raycast`
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---------
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@ -27,6 +27,7 @@ read_globals = {
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"Settings",
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"check",
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"PseudoRandom",
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"PcgRandom",
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string = {fields = {"split", "trim"}},
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table = {fields = {"copy", "getn", "indexof", "insert_all"}},
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@ -1,15 +1,37 @@
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local function test_random()
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local function test_pseudo_random()
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-- We have comprehensive unit tests in C++, this is just to make sure the API code isn't messing up
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local pr = PseudoRandom(13)
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assert(pr:next() == 22290)
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assert(pr:next() == 13854)
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local gen1 = PseudoRandom(13)
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assert(gen1:next() == 22290)
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assert(gen1:next() == 13854)
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local pr2 = PseudoRandom(-101)
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assert(pr2:next(0, 100) == 35)
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local gen2 = PseudoRandom(gen1:get_state())
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for n = 0, 16 do
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assert(gen1:next() == gen2:next())
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end
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local pr3 = PseudoRandom(-101)
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assert(pr3:next(0, 100) == 35)
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-- unusual case that is normally disallowed:
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assert(pr2:next(10000, 42767) == 12485)
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assert(pr3:next(10000, 42767) == 12485)
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end
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unittests.register("test_random", test_random)
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unittests.register("test_pseudo_random", test_pseudo_random)
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local function test_pcg_random()
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-- We have comprehensive unit tests in C++, this is just to make sure the API code isn't messing up
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local gen1 = PcgRandom(55)
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for n = 0, 16 do
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gen1:next()
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end
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local gen2 = PcgRandom(26)
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gen2:set_state(gen1:get_state())
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for n = 16, 32 do
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assert(gen1:next() == gen2:next())
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end
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end
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unittests.register("test_pcg_random", test_pcg_random)
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local function test_dynamic_media(cb, player)
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if core.get_player_information(player:get_player_name()).protocol_version < 40 then
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@ -152,6 +152,18 @@ s32 PcgRandom::randNormalDist(s32 min, s32 max, int num_trials)
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return myround((float)accum / num_trials);
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}
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void PcgRandom::getState(u64 state[2]) const
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{
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state[0] = m_state;
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state[1] = m_inc;
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}
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void PcgRandom::setState(const u64 state[2])
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{
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m_state = state[0];
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m_inc = state[1];
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}
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///////////////////////////////////////////////////////////////////////////////
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float noise2d(int x, int y, s32 seed)
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@ -76,6 +76,11 @@ public:
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return (next() % (max - min + 1)) + min;
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}
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// Allow save and restore of state
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inline s32 getState() const
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{
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return m_next;
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}
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private:
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s32 m_next;
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};
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@ -94,6 +99,9 @@ public:
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void bytes(void *out, size_t len);
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s32 randNormalDist(s32 min, s32 max, int num_trials=6);
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// Allow save and restore of state
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void getState(u64 state[2]) const;
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void setState(const u64 state[2]);
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private:
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u64 m_state;
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u64 m_inc;
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@ -425,6 +425,17 @@ int LuaPseudoRandom::l_next(lua_State *L)
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return 1;
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}
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int LuaPseudoRandom::l_get_state(lua_State *L)
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{
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NO_MAP_LOCK_REQUIRED;
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LuaPseudoRandom *o = checkObject<LuaPseudoRandom>(L, 1);
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PseudoRandom &pseudo = o->m_pseudo;
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int val = pseudo.getState();
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lua_pushinteger(L, val);
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return 1;
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}
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int LuaPseudoRandom::create_object(lua_State *L)
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{
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@ -462,6 +473,7 @@ void LuaPseudoRandom::Register(lua_State *L)
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const char LuaPseudoRandom::className[] = "PseudoRandom";
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const luaL_Reg LuaPseudoRandom::methods[] = {
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luamethod(LuaPseudoRandom, next),
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luamethod(LuaPseudoRandom, get_state),
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{0,0}
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};
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@ -496,6 +508,45 @@ int LuaPcgRandom::l_rand_normal_dist(lua_State *L)
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return 1;
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}
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int LuaPcgRandom::l_get_state(lua_State *L)
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{
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NO_MAP_LOCK_REQUIRED;
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LuaPcgRandom *o = checkObject<LuaPcgRandom>(L, 1);
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u64 state[2];
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o->m_rnd.getState(state);
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std::ostringstream oss;
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oss << std::hex << std::setw(16) << std::setfill('0')
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<< state[0] << state[1];
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lua_pushstring(L, oss.str().c_str());
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return 1;
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}
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int LuaPcgRandom::l_set_state(lua_State *L)
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{
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NO_MAP_LOCK_REQUIRED;
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LuaPcgRandom *o = checkObject<LuaPcgRandom>(L, 1);
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std::string l_string = readParam<std::string>(L, 2);
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if (l_string.size() != 32) {
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throw LuaError("PcgRandom:set_state: Expected hex string of 32 characters");
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}
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std::istringstream s_state_0(l_string.substr(0, 16));
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std::istringstream s_state_1(l_string.substr(16, 16));
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u64 state[2];
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s_state_0 >> std::hex >> state[0];
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s_state_1 >> std::hex >> state[1];
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o->m_rnd.setState(state);
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return 0;
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}
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int LuaPcgRandom::create_object(lua_State *L)
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{
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@ -536,6 +587,8 @@ const char LuaPcgRandom::className[] = "PcgRandom";
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const luaL_Reg LuaPcgRandom::methods[] = {
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luamethod(LuaPcgRandom, next),
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luamethod(LuaPcgRandom, rand_normal_dist),
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luamethod(LuaPcgRandom, get_state),
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luamethod(LuaPcgRandom, set_state),
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{0,0}
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};
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@ -116,6 +116,8 @@ private:
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// next(self, min=0, max=32767) -> get next value
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static int l_next(lua_State *L);
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// save state
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static int l_get_state(lua_State *L);
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public:
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LuaPseudoRandom(s32 seed) : m_pseudo(seed) {}
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@ -150,6 +152,9 @@ private:
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// get next normally distributed random value
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static int l_rand_normal_dist(lua_State *L);
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// save and restore state
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static int l_get_state(lua_State *L);
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static int l_set_state(lua_State *L);
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public:
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LuaPcgRandom(u64 seed) : m_rnd(seed) {}
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LuaPcgRandom(u64 seed, u64 seq) : m_rnd(seed, seq) {}
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@ -65,32 +65,39 @@ void TestRandom::testPseudoRandom()
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for (u32 i = 0; i != 256; i++)
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UASSERTEQ(s32, pr.next(), expected_pseudorandom_results[i]);
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PseudoRandom pr2(0);
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UASSERTEQ(int, pr2.next(), 0);
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UASSERTEQ(int, pr2.next(), 21469);
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UASSERTEQ(int, pr2.next(), 9989);
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s32 state = pr.getState();
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PseudoRandom pr2(state);
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PseudoRandom pr3(-101);
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UASSERTEQ(int, pr3.next(), 3267);
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UASSERTEQ(int, pr3.next(), 2485);
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UASSERTEQ(int, pr3.next(), 30057);
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for (u32 i = 0; i != 256; i++) {
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UASSERTEQ(s32, pr.next(), pr2.next());
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}
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PseudoRandom pr3(0);
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UASSERTEQ(s32, pr3.next(), 0);
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UASSERTEQ(s32, pr3.next(), 21469);
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UASSERTEQ(s32, pr3.next(), 9989);
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PseudoRandom pr4(-101);
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UASSERTEQ(s32, pr4.next(), 3267);
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UASSERTEQ(s32, pr4.next(), 2485);
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UASSERTEQ(s32, pr4.next(), 30057);
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}
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void TestRandom::testPseudoRandomRange()
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{
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PseudoRandom pr((int)time(NULL));
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PseudoRandom pr((s32)time(NULL));
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EXCEPTION_CHECK(PrngException, pr.range(2000, 8600));
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EXCEPTION_CHECK(PrngException, pr.range(5, 1));
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for (u32 i = 0; i != 32768; i++) {
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int min = (pr.next() % 3000) - 500;
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int max = (pr.next() % 3000) - 500;
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s32 min = (pr.next() % 3000) - 500;
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s32 max = (pr.next() % 3000) - 500;
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if (min > max)
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SWAP(int, min, max);
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SWAP(s32, min, max);
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int randval = pr.range(min, max);
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s32 randval = pr.range(min, max);
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UASSERT(randval >= min);
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UASSERT(randval <= max);
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}
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@ -103,12 +110,21 @@ void TestRandom::testPcgRandom()
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for (u32 i = 0; i != 256; i++)
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UASSERTEQ(u32, pr.next(), expected_pcgrandom_results[i]);
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PcgRandom pr2(0, 0);
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u64 state[2];
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pr.getState(state);
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pr2.setState(state);
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for (u32 i = 0; i != 256; i++) {
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UASSERTEQ(u32, pr.next(), pr2.next());
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}
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}
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void TestRandom::testPcgRandomRange()
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{
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PcgRandom pr((int)time(NULL));
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PcgRandom pr((u64)time(NULL));
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EXCEPTION_CHECK(PrngException, pr.range(5, 1));
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@ -116,12 +132,12 @@ void TestRandom::testPcgRandomRange()
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pr.range(pr.RANDOM_MIN, pr.RANDOM_MAX);
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for (u32 i = 0; i != 32768; i++) {
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int min = (pr.next() % 3000) - 500;
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int max = (pr.next() % 3000) - 500;
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s32 min = (pr.next() % 3000) - 500;
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s32 max = (pr.next() % 3000) - 500;
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if (min > max)
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SWAP(int, min, max);
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SWAP(s32, min, max);
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int randval = pr.range(min, max);
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s32 randval = pr.range(min, max);
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UASSERT(randval >= min);
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UASSERT(randval <= max);
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}
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@ -147,8 +163,8 @@ void TestRandom::testPcgRandomBytes()
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void TestRandom::testPcgRandomNormalDist()
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{
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static const int max = 120;
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static const int min = -120;
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static const s32 max = 120;
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static const s32 min = -120;
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static const int num_trials = 20;
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static const u32 num_samples = 61000;
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s32 bins[max - min + 1];
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