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root/group/trunk/OOPSE-4/src/math/MersenneTwister.hpp
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Comparing trunk/OOPSE-4/src/math/MersenneTwister.hpp (file contents):
Revision 2064 by tim, Tue Mar 1 03:55:13 2005 UTC vs.
Revision 2204 by gezelter, Fri Apr 15 22:04:00 2005 UTC

# Line 66 | Line 66
66   #include <stdio.h>
67   #include <time.h>
68   #include <math.h>
69 + #include <vector>
70 + namespace oopse {
71  
72 < class MTRand {
73 < // Data
74 < public:
75 <        typedef unsigned long uint32;  // unsigned integer type, at least 32 bits
72 >  class MTRand {
73 >    // Data
74 >  public:
75 >    typedef unsigned long uint32;  // unsigned integer type, at least 32 bits
76          
77 <        enum { N = 624 };       // length of state vector
78 <        enum { SAVE = N + 1 };  // length of array for save()
77 >    enum { N = 624 };       // length of state vector
78 >    enum { SAVE = N + 1 };  // length of array for save()
79  
80 < private:
81 <        enum { M = 397 };  // period parameter
80 >  private:
81 >    enum { M = 397 };  // period parameter
82          
83 <        uint32 state[N];   // internal state
84 <        uint32 *pNext;     // next value to get from state
85 <        int left;          // number of values left before reload needed
86 <        int nstrides_;
87 <        int stride_;
83 >    uint32 state[N];   // internal state
84 >    uint32 *pNext;     // next value to get from state
85 >    int left;          // number of values left before reload needed
86 >    int nstrides_;
87 >    int stride_;
88  
89 < //Methods
90 < public:
91 <        MTRand( const uint32& oneSeed, nstrides = 1, stride = 0);  // initialize with a simple uint32
92 <        MTRand( uint32 *const bigSeed, uint32 const seedLength = N, nstrides = 1, stride = 0);  // or an array
93 <        MTRand(nstrides = 1, stride = 0);  // auto-initialize with /dev/urandom or time() and clock()
89 >    //Methods
90 >  public:
91 >    MTRand( const uint32& oneSeed, int nstrides, int stride);  // initialize with a simple uint32
92 >    MTRand( uint32 *const bigSeed, uint32 const seedLength, int nstrides, int stride);  // or an array
93 >    MTRand(int nstrides, int stride);  // auto-initialize with /dev/urandom or time() and clock()
94          
95 <        // Do NOT use for CRYPTOGRAPHY without securely hashing several returned
96 <        // values together, otherwise the generator state can be learned after
97 <        // reading 624 consecutive values.
95 >    // Do NOT use for CRYPTOGRAPHY without securely hashing several returned
96 >    // values together, otherwise the generator state can be learned after
97 >    // reading 624 consecutive values.
98          
99 <        // Access to 32-bit random numbers
100 <        double rand();                          // real number in [0,1]
101 <        double rand( const double& n );         // real number in [0,n]
102 <        double randExc();                       // real number in [0,1)
103 <        double randExc( const double& n );      // real number in [0,n)
104 <        double randDblExc();                    // real number in (0,1)
105 <        double randDblExc( const double& n );   // real number in (0,n)
106 <        uint32 randInt();                       // integer in [0,2^32-1]
107 <        uint32 randInt( const uint32& n );      // integer in [0,n] for n < 2^32
108 <        double operator()() { return rand(); }  // same as rand()
99 >    // Access to 32-bit random numbers
100 >    double rand();                          // real number in [0,1]
101 >    double rand( const double& n );         // real number in [0,n]
102 >    double randExc();                       // real number in [0,1)
103 >    double randExc( const double& n );      // real number in [0,n)
104 >    double randDblExc();                    // real number in (0,1)
105 >    double randDblExc( const double& n );   // real number in (0,n)
106 >    uint32 randInt();                       // integer in [0,2^32-1] (modified for striding)
107 >    uint32 rawRandInt();                    // original randInt
108 >    uint32 randInt( const uint32& n );      // integer in [0,n] for n < 2^32
109 >    double operator()() { return rand(); }  // same as rand()
110          
111 <        // Access to 53-bit random numbers (capacity of IEEE double precision)
112 <        double rand53();  // real number in [0,1)
111 >    // Access to 53-bit random numbers (capacity of IEEE double precision)
112 >    double rand53();  // real number in [0,1)
113          
114 <        // Access to nonuniform random number distributions
115 <        double randNorm( const double& mean = 0.0, const double& variance = 0.0 );
114 >    // Access to nonuniform random number distributions
115 >    double randNorm( const double& mean = 0.0, const double& variance = 0.0 );
116          
117 <        // Re-seeding functions with same behavior as initializers
118 <        void seed( const uint32 oneSeed );
119 <        void seed( uint32 *const bigSeed, const uint32 seedLength = N );
120 <        void seed();
118 <        
119 <        // Saving and loading generator state
120 <        void save( uint32* saveArray ) const;  // to array of size SAVE
121 <        void load( uint32 *const loadArray );  // from such array
122 <        friend std::ostream& operator<<( std::ostream& os, const MTRand& mtrand );
123 <        friend std::istream& operator>>( std::istream& is, MTRand& mtrand );
117 >    // Re-seeding functions with same behavior as initializers
118 >    void seed( const uint32 oneSeed );
119 >    void seed( uint32 *const bigSeed, const uint32 seedLength = N );
120 >    void seed();
121  
122 < protected:
123 <        void initialize( const uint32 oneSeed );
124 <        void reload();
125 <        uint32 hiBit( const uint32& u ) const { return u & 0x80000000UL; }
126 <        uint32 loBit( const uint32& u ) const { return u & 0x00000001UL; }
127 <        uint32 loBits( const uint32& u ) const { return u & 0x7fffffffUL; }
128 <        uint32 mixBits( const uint32& u, const uint32& v ) const
132 <                { return hiBit(u) | loBits(v); }
133 <        uint32 twist( const uint32& m, const uint32& s0, const uint32& s1 ) const
134 <                { return m ^ (mixBits(s0,s1)>>1) ^ (-loBit(s1) & 0x9908b0dfUL); }
135 <        static uint32 hash( time_t t, clock_t c );
136 < };
122 >    std::vector<uint32>generateSeeds();
123 >        
124 >    // Saving and loading generator state
125 >    void save( uint32* saveArray ) const;  // to array of size SAVE
126 >    void load( uint32 *const loadArray );  // from such array
127 >    friend std::ostream& operator<<( std::ostream& os, const MTRand& mtrand );
128 >    friend std::istream& operator>>( std::istream& is, MTRand& mtrand );
129  
130 +  protected:
131 +    void initialize( const uint32 oneSeed );
132 +    void reload();
133 +    uint32 hiBit( const uint32& u ) const { return u & 0x80000000UL; }
134 +    uint32 loBit( const uint32& u ) const { return u & 0x00000001UL; }
135 +    uint32 loBits( const uint32& u ) const { return u & 0x7fffffffUL; }
136 +    uint32 mixBits( const uint32& u, const uint32& v ) const
137 +    { return hiBit(u) | loBits(v); }
138 +    uint32 twist( const uint32& m, const uint32& s0, const uint32& s1 ) const
139 +    { return m ^ (mixBits(s0,s1)>>1) ^ (-loBit(s1) & 0x9908b0dfUL); }
140 +    static uint32 hash( time_t t, clock_t c );
141 +  };
142  
143 < inline MTRand::MTRand( const uint32& oneSeed, int nstrides, int stride) : nstrides_(nstrides), stride_(stride) {
143 >
144 >  inline MTRand::MTRand( const uint32& oneSeed, int nstrides, int stride) : nstrides_(nstrides), stride_(stride) {
145      assert(stride_ < nstrides_ && stride_ >= 0);
146      seed(oneSeed);
147 < }
147 >  }
148  
149 < inline MTRand::MTRand( uint32 *const bigSeed, const uint32 seedLength, int nstrides, int stride) : nstrides_(nstrides), stride_(stride) {
149 >  inline MTRand::MTRand( uint32 *const bigSeed, const uint32 seedLength, int nstrides, int stride) : nstrides_(nstrides), stride_(stride) {
150      assert(stride_ < nstrides_ && stride_ >= 0);
151      seed(bigSeed,seedLength);
152 < }
152 >  }
153  
154 < inline MTRand::MTRand(int nstrides, int stride) : nstrides_(nstrides), stride_(stride){
154 >  inline MTRand::MTRand(int nstrides, int stride)       : nstrides_(nstrides), stride_(stride){
155      assert(stride_ < nstrides_ && stride_ >= 0);
156      seed();
157 < }
157 >  }
158  
159 < inline double MTRand::rand()
160 <        { return double(randInt()) * (1.0/4294967295.0); }
159 >  inline double MTRand::rand()
160 >  { return double(randInt()) * (1.0/4294967295.0); }
161  
162 < inline double MTRand::rand( const double& n )
163 <        { return rand() * n; }
162 >  inline double MTRand::rand( const double& n )
163 >  { return rand() * n; }
164  
165 < inline double MTRand::randExc()
166 <        { return double(randInt()) * (1.0/4294967296.0); }
165 >  inline double MTRand::randExc()
166 >  { return double(randInt()) * (1.0/4294967296.0); }
167  
168 < inline double MTRand::randExc( const double& n )
169 <        { return randExc() * n; }
168 >  inline double MTRand::randExc( const double& n )
169 >  { return randExc() * n; }
170  
171 < inline double MTRand::randDblExc()
172 <        { return ( double(randInt()) + 0.5 ) * (1.0/4294967296.0); }
171 >  inline double MTRand::randDblExc()
172 >  { return ( double(randInt()) + 0.5 ) * (1.0/4294967296.0); }
173  
174 < inline double MTRand::randDblExc( const double& n )
175 <        { return randDblExc() * n; }
174 >  inline double MTRand::randDblExc( const double& n )
175 >  { return randDblExc() * n; }
176  
177 < inline double MTRand::rand53()
178 < {
179 <        uint32 a = randInt() >> 5, b = randInt() >> 6;
180 <        return ( a * 67108864.0 + b ) * (1.0/9007199254740992.0);  // by Isaku Wada
181 < }
177 >  inline double MTRand::rand53()
178 >  {
179 >    uint32 a = randInt() >> 5, b = randInt() >> 6;
180 >    return ( a * 67108864.0 + b ) * (1.0/9007199254740992.0);  // by Isaku Wada
181 >  }
182  
183 < inline double MTRand::randNorm( const double& mean, const double& variance )
184 < {
185 <        // Return a real number from a normal (Gaussian) distribution with given
186 <        // mean and variance by Box-Muller method
187 <        double r = sqrt( -2.0 * log( 1.0-randDblExc()) ) * variance;
188 <        double phi = 2.0 * 3.14159265358979323846264338328 * randExc();
189 <        return mean + r * cos(phi);
190 < }
183 >  inline double MTRand::randNorm( const double& mean, const double& variance )
184 >  {
185 >    // Return a real number from a normal (Gaussian) distribution with given
186 >    // mean and variance by Box-Muller method
187 >    double r = sqrt( -2.0 * log( 1.0-randDblExc()) ) * variance;
188 >    double phi = 2.0 * 3.14159265358979323846264338328 * randExc();
189 >    return mean + r * cos(phi);
190 >  }
191  
192 < inline MTRand::uint32 MTRand::randInt()
193 < {
194 <        // Pull a 32-bit integer from the generator state
195 <        // Every other access function simply transforms the numbers extracted here
192 >  /**
193 >   * This function is modified from the original to allow for random
194 >   * streams on parallel jobs.  It now takes numbers from by striding
195 >   * through the random stream and picking up only one of the random
196 >   * numbers per nstrides_.  The number it picks is the stride_'th
197 >   * number in the stride sequence.  
198 >   */
199 >  inline MTRand::uint32 MTRand::randInt() {
200 >
201 >    std::vector<uint32> ranNums(nstrides_);
202 >  
203 >    for (int i = 0; i < nstrides_; ++i) {
204 >      ranNums[i] = rawRandInt();
205 >    }
206 >  
207 >    return ranNums[stride_];
208 >  }
209  
210 <        uint32 ranNums[nstrides];
210 >  /**
211 >   * This is the original randInt function which implements the mersenne
212 >   * twister.
213 >   */
214 >  inline MTRand::uint32 MTRand::rawRandInt()
215 >  {
216 >    // Pull a 32-bit integer from the generator state
217 >    // Every other access function simply transforms the numbers extracted here
218 >        
219 >    if( left == 0 ) reload();
220 >    --left;
221 >                
222 >    register uint32 s1;
223 >    s1 = *pNext++;
224 >    s1 ^= (s1 >> 11);
225 >    s1 ^= (s1 <<  7) & 0x9d2c5680UL;
226 >    s1 ^= (s1 << 15) & 0xefc60000UL;
227 >    return ( s1 ^ (s1 >> 18) );
228 >  }
229  
230 <        for (int i = 0; i < nstrides; ++i) {
231 <            if( left == 0 ) {
232 <                reload();
233 <            }
234 <            
235 <            --left;
230 >  inline MTRand::uint32 MTRand::randInt( const uint32& n )
231 >  {
232 >    // Find which bits are used in n
233 >    // Optimized by Magnus Jonsson (magnus@smartelectronix.com)
234 >    uint32 used = n;
235 >    used |= used >> 1;
236 >    used |= used >> 2;
237 >    used |= used >> 4;
238 >    used |= used >> 8;
239 >    used |= used >> 16;
240 >        
241 >    // Draw numbers until one is found in [0,n]
242 >    uint32 i;
243 >    do
244 >      i = randInt() & used;  // toss unused bits to shorten search
245 >    while( i > n );
246 >    return i;
247 >  }
248  
201 –            register uint32 s1;
202 –            s1 = *pNext++;
203 –            s1 ^= (s1 >> 11);
204 –            s1 ^= (s1 <<  7) & 0x9d2c5680UL;
205 –            s1 ^= (s1 << 15) & 0xefc60000UL;
206 –            ranNums[i] = s1 ^ (s1 >> 18) );
207 –        }
249  
250 <        return ranNums[stride];
251 < }
250 >  inline void MTRand::seed( const uint32 oneSeed )
251 >  {
252 >    // Seed the generator with a simple uint32
253 >    initialize(oneSeed);
254 >    reload();
255 >  }
256  
212 – inline MTRand::uint32 MTRand::randInt( const uint32& n )
213 – {
214 –        // Find which bits are used in n
215 –        // Optimized by Magnus Jonsson (magnus@smartelectronix.com)
216 –        uint32 used = n;
217 –        used |= used >> 1;
218 –        used |= used >> 2;
219 –        used |= used >> 4;
220 –        used |= used >> 8;
221 –        used |= used >> 16;
222 –        
223 –        // Draw numbers until one is found in [0,n]
224 –        uint32 i;
225 –        do
226 –                i = randInt() & used;  // toss unused bits to shorten search
227 –        while( i > n );
228 –        return i;
229 – }
257  
258 <
259 < inline void MTRand::seed( const uint32 oneSeed )
260 < {
261 <        // Seed the generator with a simple uint32
262 <        initialize(oneSeed);
263 <        reload();
264 < }
258 >  inline void MTRand::seed( uint32 *const bigSeed, const uint32 seedLength )
259 >  {
260 >    // Seed the generator with an array of uint32's
261 >    // There are 2^19937-1 possible initial states.  This function allows
262 >    // all of those to be accessed by providing at least 19937 bits (with a
263 >    // default seed length of N = 624 uint32's).  Any bits above the lower 32
264 >    // in each element are discarded.
265 >    // Just call seed() if you want to get array from /dev/urandom
266 >    initialize(19650218UL);
267 >    register int i = 1;
268 >    register uint32 j = 0;
269 >    register int k = ( N > seedLength ? N : seedLength );
270 >    for( ; k; --k )
271 >      {
272 >        state[i] =
273 >          state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1664525UL );
274 >        state[i] += ( bigSeed[j] & 0xffffffffUL ) + j;
275 >        state[i] &= 0xffffffffUL;
276 >        ++i;  ++j;
277 >        if( i >= N ) { state[0] = state[N-1];  i = 1; }
278 >        if( j >= seedLength ) j = 0;
279 >      }
280 >    for( k = N - 1; k; --k )
281 >      {
282 >        state[i] =
283 >          state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1566083941UL );
284 >        state[i] -= i;
285 >        state[i] &= 0xffffffffUL;
286 >        ++i;
287 >        if( i >= N ) { state[0] = state[N-1];  i = 1; }
288 >      }
289 >    state[0] = 0x80000000UL;  // MSB is 1, assuring non-zero initial array
290 >    reload();
291 >  }
292  
293  
294 < inline void MTRand::seed( uint32 *const bigSeed, const uint32 seedLength )
295 < {
296 <        // Seed the generator with an array of uint32's
243 <        // There are 2^19937-1 possible initial states.  This function allows
244 <        // all of those to be accessed by providing at least 19937 bits (with a
245 <        // default seed length of N = 624 uint32's).  Any bits above the lower 32
246 <        // in each element are discarded.
247 <        // Just call seed() if you want to get array from /dev/urandom
248 <        initialize(19650218UL);
249 <        register int i = 1;
250 <        register uint32 j = 0;
251 <        register int k = ( N > seedLength ? N : seedLength );
252 <        for( ; k; --k )
253 <        {
254 <                state[i] =
255 <                        state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1664525UL );
256 <                state[i] += ( bigSeed[j] & 0xffffffffUL ) + j;
257 <                state[i] &= 0xffffffffUL;
258 <                ++i;  ++j;
259 <                if( i >= N ) { state[0] = state[N-1];  i = 1; }
260 <                if( j >= seedLength ) j = 0;
261 <        }
262 <        for( k = N - 1; k; --k )
263 <        {
264 <                state[i] =
265 <                        state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1566083941UL );
266 <                state[i] -= i;
267 <                state[i] &= 0xffffffffUL;
268 <                ++i;
269 <                if( i >= N ) { state[0] = state[N-1];  i = 1; }
270 <        }
271 <        state[0] = 0x80000000UL;  // MSB is 1, assuring non-zero initial array
272 <        reload();
273 < }
294 >  inline void MTRand::seed()
295 >  {
296 >    std::vector<uint32> seeds;
297  
298 +    seeds = generateSeeds();
299  
300 < inline void MTRand::seed()
301 < {
302 <        // Seed the generator with an array from /dev/urandom if available
303 <        // Otherwise use a hash of time() and clock() values
304 <        
305 <        // First try getting an array from /dev/urandom
282 <        FILE* urandom = fopen( "/dev/urandom", "rb" );
283 <        if( urandom )
284 <        {
285 <                uint32 bigSeed[N];
286 <                register uint32 *s = bigSeed;
287 <                register int i = N;
288 <                register bool success = true;
289 <                while( success && i-- )
290 <                        success = fread( s++, sizeof(uint32), 1, urandom );
291 <                fclose(urandom);
292 <                if( success ) { seed( bigSeed, N );  return; }
293 <        }
294 <        
295 <        // Was not successful, so use time() and clock() instead
296 <        seed( hash( time(NULL), clock() ) );
297 < }
300 >    if (seeds.size() == 1) {
301 >      seed( seeds[0] );
302 >    } else {
303 >      seed( &seeds[0], seeds.size() );
304 >    }
305 >  }
306  
307  
308 < inline void MTRand::initialize( const uint32 seed )
309 < {
310 <        // Initialize generator state with seed
303 <        // See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier.
304 <        // In previous versions, most significant bits (MSBs) of the seed affect
305 <        // only MSBs of the state array.  Modified 9 Jan 2002 by Makoto Matsumoto.
306 <        register uint32 *s = state;
307 <        register uint32 *r = state;
308 <        register int i = 1;
309 <        *s++ = seed & 0xffffffffUL;
310 <        for( ; i < N; ++i )
311 <        {
312 <                *s++ = ( 1812433253UL * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffUL;
313 <                r++;
314 <        }
315 < }
308 >  inline std::vector<MTRand::uint32> MTRand::generateSeeds() {
309 >    // Seed the generator with an array from /dev/urandom if available
310 >    // Otherwise use a hash of time() and clock() values
311  
312 +    std::vector<uint32> bigSeed;
313  
314 < inline void MTRand::reload()
315 < {
316 <        // Generate N new values in state
317 <        // Made clearer and faster by Matthew Bellew (matthew.bellew@home.com)
318 <        register uint32 *p = state;
319 <        register int i;
320 <        for( i = N - M; i--; ++p )
321 <                *p = twist( p[M], p[0], p[1] );
322 <        for( i = M; --i; ++p )
323 <                *p = twist( p[M-N], p[0], p[1] );
324 <        *p = twist( p[M-N], p[0], state[0] );
314 >    // First try getting an array from /dev/urandom
315 >    FILE* urandom = fopen( "/dev/urandom", "rb" );
316 >    if( urandom )
317 >      {
318 >        bigSeed.resize(N);
319 >        register uint32 *s = &bigSeed[0];
320 >        register int i = N;
321 >        register bool success = true;
322 >        while( success && i-- )
323 >          success = fread( s++, sizeof(uint32), 1, urandom );
324 >        fclose(urandom);
325 >        if( success ) { return bigSeed; }
326 >      }
327 >  
328 >    // Was not successful, so use time() and clock() instead
329  
330 <        left = N, pNext = state;
331 < }
330 >    bigSeed.push_back(hash( time(NULL), clock()));
331 >    return bigSeed;
332 >  }
333  
334  
335 < inline MTRand::uint32 MTRand::hash( time_t t, clock_t c )
336 < {
337 <        // Get a uint32 from t and c
338 <        // Better than uint32(x) in case x is floating point in [0,1]
339 <        // Based on code by Lawrence Kirby (fred@genesis.demon.co.uk)
335 >  inline void MTRand::initialize( const uint32 seed )
336 >  {
337 >    // Initialize generator state with seed
338 >    // See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier.
339 >    // In previous versions, most significant bits (MSBs) of the seed affect
340 >    // only MSBs of the state array.  Modified 9 Jan 2002 by Makoto Matsumoto.
341 >    register uint32 *s = state;
342 >    register uint32 *r = state;
343 >    register int i = 1;
344 >    *s++ = seed & 0xffffffffUL;
345 >    for( ; i < N; ++i )
346 >      {
347 >        *s++ = ( 1812433253UL * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffUL;
348 >        r++;
349 >      }
350 >  }
351  
340 –        static uint32 differ = 0;  // guarantee time-based seeds will change
352  
353 <        uint32 h1 = 0;
354 <        unsigned char *p = (unsigned char *) &t;
355 <        for( size_t i = 0; i < sizeof(t); ++i )
356 <        {
357 <                h1 *= UCHAR_MAX + 2U;
358 <                h1 += p[i];
359 <        }
360 <        uint32 h2 = 0;
361 <        p = (unsigned char *) &c;
362 <        for( size_t j = 0; j < sizeof(c); ++j )
363 <        {
353 <                h2 *= UCHAR_MAX + 2U;
354 <                h2 += p[j];
355 <        }
356 <        return ( h1 + differ++ ) ^ h2;
357 < }
353 >  inline void MTRand::reload()
354 >  {
355 >    // Generate N new values in state
356 >    // Made clearer and faster by Matthew Bellew (matthew.bellew@home.com)
357 >    register uint32 *p = state;
358 >    register int i;
359 >    for( i = N - M; i--; ++p )
360 >      *p = twist( p[M], p[0], p[1] );
361 >    for( i = M; --i; ++p )
362 >      *p = twist( p[M-N], p[0], p[1] );
363 >    *p = twist( p[M-N], p[0], state[0] );
364  
365 +    left = N, pNext = state;
366 +  }
367  
360 – inline void MTRand::save( uint32* saveArray ) const
361 – {
362 –        register uint32 *sa = saveArray;
363 –        register const uint32 *s = state;
364 –        register int i = N;
365 –        for( ; i--; *sa++ = *s++ ) {}
366 –        *sa = left;
367 – }
368  
369 +  inline MTRand::uint32 MTRand::hash( time_t t, clock_t c )
370 +  {
371 +    // Get a uint32 from t and c
372 +    // Better than uint32(x) in case x is floating point in [0,1]
373 +    // Based on code by Lawrence Kirby (fred@genesis.demon.co.uk)
374  
375 < inline void MTRand::load( uint32 *const loadArray )
371 < {
372 <        register uint32 *s = state;
373 <        register uint32 *la = loadArray;
374 <        register int i = N;
375 <        for( ; i--; *s++ = *la++ ) {}
376 <        left = *la;
377 <        pNext = &state[N-left];
378 < }
375 >    static uint32 differ = 0;  // guarantee time-based seeds will change
376  
377 +    uint32 h1 = 0;
378 +    unsigned char *p = (unsigned char *) &t;
379 +    for( size_t i = 0; i < sizeof(t); ++i )
380 +      {
381 +        h1 *= UCHAR_MAX + 2U;
382 +        h1 += p[i];
383 +      }
384 +    uint32 h2 = 0;
385 +    p = (unsigned char *) &c;
386 +    for( size_t j = 0; j < sizeof(c); ++j )
387 +      {
388 +        h2 *= UCHAR_MAX + 2U;
389 +        h2 += p[j];
390 +      }
391 +    return ( h1 + differ++ ) ^ h2;
392 +  }
393  
381 – inline std::ostream& operator<<( std::ostream& os, const MTRand& mtrand )
382 – {
383 –        register const MTRand::uint32 *s = mtrand.state;
384 –        register int i = mtrand.N;
385 –        for( ; i--; os << *s++ << "\t" ) {}
386 –        return os << mtrand.left;
387 – }
394  
395 +  inline void MTRand::save( uint32* saveArray ) const
396 +  {
397 +    register uint32 *sa = saveArray;
398 +    register const uint32 *s = state;
399 +    register int i = N;
400 +    for( ; i--; *sa++ = *s++ ) {}
401 +    *sa = left;
402 +  }
403  
390 – inline std::istream& operator>>( std::istream& is, MTRand& mtrand )
391 – {
392 –        register MTRand::uint32 *s = mtrand.state;
393 –        register int i = mtrand.N;
394 –        for( ; i--; is >> *s++ ) {}
395 –        is >> mtrand.left;
396 –        mtrand.pNext = &mtrand.state[mtrand.N-mtrand.left];
397 –        return is;
398 – }
404  
405 +  inline void MTRand::load( uint32 *const loadArray )
406 +  {
407 +    register uint32 *s = state;
408 +    register uint32 *la = loadArray;
409 +    register int i = N;
410 +    for( ; i--; *s++ = *la++ ) {}
411 +    left = *la;
412 +    pNext = &state[N-left];
413 +  }
414 +
415 +
416 +  inline std::ostream& operator<<( std::ostream& os, const MTRand& mtrand )
417 +  {
418 +    register const MTRand::uint32 *s = mtrand.state;
419 +    register int i = mtrand.N;
420 +    for( ; i--; os << *s++ << "\t" ) {}
421 +    return os << mtrand.left;
422 +  }
423 +
424 +
425 +  inline std::istream& operator>>( std::istream& is, MTRand& mtrand )
426 +  {
427 +    register MTRand::uint32 *s = mtrand.state;
428 +    register int i = mtrand.N;
429 +    for( ; i--; is >> *s++ ) {}
430 +    is >> mtrand.left;
431 +    mtrand.pNext = &mtrand.state[mtrand.N-mtrand.left];
432 +    return is;
433 +  }
434 +
435 + }
436   #endif  // MERSENNETWISTER_H
437  
438   // Change log:

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