Changeset 611f29d for libcfa/src/bits/random.hfa

Timestamp:

Jan 13, 2022, 9:30:38 PM (2 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

919a6b2

Parents:

f520c4c

Message:

consolidate random-number generators

File:

• libcfa/src/bits/random.hfa (modified) (4 diffs)

libcfa/src/bits/random.hfa

@@ -3 +3 @@
 #include <stdint.h>
 
+// Pipelined to allow out-of-order overlap with reduced dependencies. Critically, return the current value, and compute
+// and store the next value.
+
 //--------------------------------------------------
 #if defined(__SIZEOF_INT128__)
-        typedef __uint128_t __lehmer64_state_t;
-        static inline uint64_t __lehmer64( __lehmer64_state_t & state ) {
+        static inline uint64_t lehmer64( __uint128_t & state ) {
+                __uint128_t ret = state;
                 state *= 0xda942042e4dd58b5;
-                return state >> 64;
+                return ret >> 64;
         }
 
 //--------------------------------------------------
-        typedef uint64_t __wyhash64_state_t;
-        static inline uint64_t __wyhash64( __wyhash64_state_t & state ) {
+        static inline uint64_t wyhash64( uint64_t & state ) {
                 state += 0x60bee2bee120fc15;
                 __uint128_t tmp;
@@ -25 +27 @@
 
 //--------------------------------------------------
-typedef uint64_t __xorshift64_state_t;
-static inline uint64_t __xorshift64( __xorshift64_state_t & state ) {
-        uint64_t x = state;
-        x ^= x << 13;
-        x ^= x >> 7;
-        x ^= x << 17;
-        return state = x;
+static inline uint64_t xorshift_13_7_17( uint64_t & state ) {
+        uint64_t ret = state;
+        state ^= state << 13;
+        state ^= state >> 7;
+        state ^= state << 17;
+        return ret;
 }
+
+//--------------------------------------------------
+static inline uint32_t xorshift_6_21_7( uint32_t & state ) {
+        uint32_t ret = state;
+        state ^= state << 6;
+        state ^= state >> 21;
+        state ^= state << 7;
+        return ret;
+} // xorshift_6_21_7
 
 //--------------------------------------------------
@@ -38 +48 @@
   uint32_t a, b, c, d;
   uint32_t counter;
-} __xorwow__state_t;
+} xorwow__state_t;
 
 /* The state array must be initialized to not be all zero in the first four words */
-static inline uint32_t __xorwow( __xorwow__state_t & state ) {
+static inline uint32_t xorwow( xorwow__state_t & state ) {
         /* Algorithm "xorwow" from p. 5 of Marsaglia, "Xorshift RNGs" */
+        uint32_t ret = state.a + state.counter;
         uint32_t t = state.d;
 
@@ -56 +67 @@
 
         state.counter += 362437;
-        return t + state.counter;
+        return ret;
 }
+
+//--------------------------------------------------
+static inline uint32_t LCG( uint32_t & state ) {                // linear congruential generator
+        uint32_t ret = state;
+        state = 36969 * (state & 65535) + (state >> 16);        // 36969 is NOT prime! No not change it!
+        return ret;
+} // LCG
+
+//--------------------------------------------------
+#define M  (1_l64u << 48_l64u)
+#define A  (25214903917_l64u)
+#define AI (18446708753438544741_l64u)
+#define C  (11_l64u)
+#define D  (16_l64u)
+
+static inline uint32_t LCGBI_fwd( uint64_t & state ) {
+        state = (A * state + C) & (M - 1);
+        return state >> D;
+}
+
+static inline uint32_t LCGBI_bck( uint64_t & state ) {
+        unsigned int r = state >> D;
+        state = AI * (state - C) & (M - 1);
+        return r;
+}
+
+#undef M
+#undef A
+#undef AI
+#undef C
+#undef D