diff options
Diffstat (limited to 'src/pkg/rand/rng.go')
| -rw-r--r-- | src/pkg/rand/rng.go | 68 |
1 files changed, 34 insertions, 34 deletions
diff --git a/src/pkg/rand/rng.go b/src/pkg/rand/rng.go index a8f7a18b1..947c49f0f 100644 --- a/src/pkg/rand/rng.go +++ b/src/pkg/rand/rng.go @@ -12,14 +12,14 @@ package rand */ const ( - _LEN = 607; - _TAP = 273; - _MAX = 1 << 63; - _MASK = _MAX - 1; - _A = 48271; - _M = (1 << 31) - 1; - _Q = 44488; - _R = 3399; + _LEN = 607 + _TAP = 273 + _MAX = 1 << 63 + _MASK = _MAX - 1 + _A = 48271 + _M = (1 << 31) - 1 + _Q = 44488 + _R = 3399 ) var ( @@ -179,32 +179,32 @@ var ( 4922828954023452664, 2879211533496425641, 5896236396443472108, 8465043815351752425, 7329020396871624740, 8915471717014488588, 2944902635677463047, 7052079073493465134, 8382142935188824023, 9103922860780351547, 4152330101494654406, - }; + } ) type rngSource struct { - tap int; // index into vec - feed int; // index into vec - vec [_LEN]int64; // current feedback register + tap int // index into vec + feed int // index into vec + vec [_LEN]int64 // current feedback register } // seed rng x[n+1] = 48271 * x[n] mod (2**31 - 1) func seedrand(x int32) int32 { - hi := x / _Q; - lo := x % _Q; - x = _A*lo - _R*hi; + hi := x / _Q + lo := x % _Q + x = _A*lo - _R*hi if x < 0 { x += _M } - return x; + return x } // Seed uses the provided seed value to initialize the generator to a deterministic state. func (rng *rngSource) Seed(seed int64) { - rng.tap = 0; - rng.feed = _LEN - _TAP; + rng.tap = 0 + rng.feed = _LEN - _TAP - seed = seed % _M; + seed = seed % _M if seed < 0 { seed += _M } @@ -212,35 +212,35 @@ func (rng *rngSource) Seed(seed int64) { seed = 89482311 } - x := int32(seed); + x := int32(seed) for i := -20; i < _LEN; i++ { - x = seedrand(x); + x = seedrand(x) if i >= 0 { - var u int64; - u = int64(x) << 40; - x = seedrand(x); - u ^= int64(x) << 20; - x = seedrand(x); - u ^= int64(x); - u ^= rng_cooked[i]; - rng.vec[i] = u & _MASK; + var u int64 + u = int64(x) << 40 + x = seedrand(x) + u ^= int64(x) << 20 + x = seedrand(x) + u ^= int64(x) + u ^= rng_cooked[i] + rng.vec[i] = u & _MASK } } } // Int63 returns a non-negative pseudo-random 63-bit integer as an int64. func (rng *rngSource) Int63() int64 { - rng.tap--; + rng.tap-- if rng.tap < 0 { rng.tap += _LEN } - rng.feed--; + rng.feed-- if rng.feed < 0 { rng.feed += _LEN } - x := (rng.vec[rng.feed] + rng.vec[rng.tap]) & _MASK; - rng.vec[rng.feed] = x; - return x; + x := (rng.vec[rng.feed] + rng.vec[rng.tap]) & _MASK + rng.vec[rng.feed] = x + return x } |