ViewVC Help
View File | Revision Log | Show Annotations | View Changeset | Root Listing
root/OpenMD/trunk/src/math/MersenneTwister.hpp
(Generate patch)

Comparing trunk/src/math/MersenneTwister.hpp (file contents):
Revision 385 by tim, Tue Mar 1 20:10:14 2005 UTC vs.
Revision 904 by tim, Thu Mar 16 22:50:48 2006 UTC

# Line 69 | Line 69 | namespace oopse {
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, int nstrides = 1, int stride = 0);  // initialize with a simple uint32
92 <        MTRand( uint32 *const bigSeed, uint32 const seedLength = N, int nstrides = 1, int stride = 0);  // or an array
93 <        MTRand(int nstrides = 1, int 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] (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()
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();
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 <        std::vector<uint32>generateSeeds();    
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 );
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 < };
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  
144 < inline MTRand::MTRand( const uint32& oneSeed, int nstrides, int stride) : nstrides_(nstrides), stride_(stride) {
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 >    assert(variance > 0);
188 >    double r = sqrt( -2.0 * log( 1.0-randDblExc()) * variance);
189 >    double phi = 2.0 * 3.14159265358979323846264338328 * randExc();
190 >    return mean + r * cos(phi);
191 >  }
192  
193 < /**
194 < * This function is modified from the original to allow for random
195 < * streams on parallel jobs.  It now takes numbers from by striding
196 < * through the random stream and picking up only one of the random
197 < * numbers per nstrides_.  The number it picks is the stride_'th
198 < * number in the stride sequence.  
199 < */
200 < inline MTRand::uint32 MTRand::randInt() {
193 >  /**
194 >   * This function is modified from the original to allow for random
195 >   * streams on parallel jobs.  It now takes numbers from by striding
196 >   * through the random stream and picking up only one of the random
197 >   * numbers per nstrides_.  The number it picks is the stride_'th
198 >   * number in the stride sequence.  
199 >   */
200 >  inline MTRand::uint32 MTRand::randInt() {
201  
202 <  std::vector<uint32> ranNums(nstrides_);
202 >    std::vector<uint32> ranNums(nstrides_);
203    
204 <  for (int i = 0; i < nstrides_; ++i) {
205 <    ranNums[i] = rawRandInt();
206 <  }
204 >    for (int i = 0; i < nstrides_; ++i) {
205 >      ranNums[i] = rawRandInt();
206 >    }
207    
208 <  return ranNums[stride_];
209 < }
208 >    return ranNums[stride_];
209 >  }
210  
211 < /**
212 < * This is the original randInt function which implements the mersenne
213 < * twister.
214 < */
215 < inline MTRand::uint32 MTRand::rawRandInt()
216 < {
217 <        // Pull a 32-bit integer from the generator state
218 <        // Every other access function simply transforms the numbers extracted here
211 >  /**
212 >   * This is the original randInt function which implements the mersenne
213 >   * twister.
214 >   */
215 >  inline MTRand::uint32 MTRand::rawRandInt()
216 >  {
217 >    // Pull a 32-bit integer from the generator state
218 >    // Every other access function simply transforms the numbers extracted here
219          
220 <        if( left == 0 ) reload();
221 <        --left;
220 >    if( left == 0 ) reload();
221 >    --left;
222                  
223 <        register uint32 s1;
224 <        s1 = *pNext++;
225 <        s1 ^= (s1 >> 11);
226 <        s1 ^= (s1 <<  7) & 0x9d2c5680UL;
227 <        s1 ^= (s1 << 15) & 0xefc60000UL;
228 <        return ( s1 ^ (s1 >> 18) );
229 < }
223 >    register uint32 s1;
224 >    s1 = *pNext++;
225 >    s1 ^= (s1 >> 11);
226 >    s1 ^= (s1 <<  7) & 0x9d2c5680UL;
227 >    s1 ^= (s1 << 15) & 0xefc60000UL;
228 >    return ( s1 ^ (s1 >> 18) );
229 >  }
230  
231 < inline MTRand::uint32 MTRand::randInt( const uint32& n )
232 < {
233 <        // Find which bits are used in n
234 <        // Optimized by Magnus Jonsson (magnus@smartelectronix.com)
235 <        uint32 used = n;
236 <        used |= used >> 1;
237 <        used |= used >> 2;
238 <        used |= used >> 4;
239 <        used |= used >> 8;
240 <        used |= used >> 16;
241 <        
242 <        // Draw numbers until one is found in [0,n]
243 <        uint32 i;
244 <        do
245 <                i = randInt() & used;  // toss unused bits to shorten search
246 <        while( i > n );
247 <        return i;
248 < }
248 <
249 <
250 < inline void MTRand::seed( const uint32 oneSeed )
251 < {
252 <        // Seed the generator with a simple uint32
253 <        initialize(oneSeed);
254 <        reload();
255 < }
256 <
257 <
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()
295 < {
296 <  std::vector<uint32> seeds;
297 <
298 <  seeds = generateSeeds();
231 >  inline MTRand::uint32 MTRand::randInt( const uint32& n )
232 >  {
233 >    // Find which bits are used in n
234 >    // Optimized by Magnus Jonsson (magnus@smartelectronix.com)
235 >    uint32 used = n;
236 >    used |= used >> 1;
237 >    used |= used >> 2;
238 >    used |= used >> 4;
239 >    used |= used >> 8;
240 >    used |= used >> 16;
241 >        
242 >    // Draw numbers until one is found in [0,n]
243 >    uint32 i;
244 >    do
245 >      i = randInt() & used;  // toss unused bits to shorten search
246 >    while( i > n );
247 >    return i;
248 >  }
249  
250 <  if (seeds.size() == 1) {
251 <    seed( seeds[0] );
252 <  } else {
253 <    seed( &seeds[0], seeds.size() );
250 >
251 >  inline void MTRand::seed( const uint32 oneSeed )
252 >  {
253 >    // Seed the generator with a simple uint32
254 >    initialize(oneSeed);
255 >    reload();
256    }
305 – }
257  
258  
259 < inline std::vector<MTRand::uint32> MTRand::generateSeeds() {
260 <  // Seed the generator with an array from /dev/urandom if available
261 <  // Otherwise use a hash of time() and clock() values
259 >  inline void MTRand::seed( uint32 *const bigSeed, const uint32 seedLength )
260 >  {
261 >    // Seed the generator with an array of uint32's
262 >    // There are 2^19937-1 possible initial states.  This function allows
263 >    // all of those to be accessed by providing at least 19937 bits (with a
264 >    // default seed length of N = 624 uint32's).  Any bits above the lower 32
265 >    // in each element are discarded.
266 >    // Just call seed() if you want to get array from /dev/urandom
267 >    initialize(19650218UL);
268 >    register int i = 1;
269 >    register uint32 j = 0;
270 >    register int k = ( N > seedLength ? N : seedLength );
271 >    for( ; k; --k )
272 >      {
273 >        state[i] =
274 >          state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1664525UL );
275 >        state[i] += ( bigSeed[j] & 0xffffffffUL ) + j;
276 >        state[i] &= 0xffffffffUL;
277 >        ++i;  ++j;
278 >        if( i >= N ) { state[0] = state[N-1];  i = 1; }
279 >        if( j >= seedLength ) j = 0;
280 >      }
281 >    for( k = N - 1; k; --k )
282 >      {
283 >        state[i] =
284 >          state[i] ^ ( (state[i-1] ^ (state[i-1] >> 30)) * 1566083941UL );
285 >        state[i] -= i;
286 >        state[i] &= 0xffffffffUL;
287 >        ++i;
288 >        if( i >= N ) { state[0] = state[N-1];  i = 1; }
289 >      }
290 >    state[0] = 0x80000000UL;  // MSB is 1, assuring non-zero initial array
291 >    reload();
292 >  }
293  
312 –  std::vector<uint32> bigSeed;
294  
295 <  // First try getting an array from /dev/urandom
296 <  FILE* urandom = fopen( "/dev/urandom", "rb" );
297 <  if( urandom )
298 <    {
299 <      bigSeed.resize(N);
300 <      register uint32 *s = &bigSeed[0];
301 <      register int i = N;
302 <      register bool success = true;
303 <      while( success && i-- )
304 <        success = fread( s++, sizeof(uint32), 1, urandom );
324 <      fclose(urandom);
325 <      if( success ) { return bigSeed; }
295 >  inline void MTRand::seed()
296 >  {
297 >    std::vector<uint32> seeds;
298 >
299 >    seeds = generateSeeds();
300 >
301 >    if (seeds.size() == 1) {
302 >      seed( seeds[0] );
303 >    } else {
304 >      seed( &seeds[0], seeds.size() );
305      }
306 +  }
307 +
308 +
309 +  inline std::vector<MTRand::uint32> MTRand::generateSeeds() {
310 +    // Seed the generator with an array from /dev/urandom if available
311 +    // Otherwise use a hash of time() and clock() values
312 +
313 +    std::vector<uint32> bigSeed;
314 +
315 +    // First try getting an array from /dev/urandom
316 +    FILE* urandom = fopen( "/dev/urandom", "rb" );
317 +    if( urandom )
318 +      {
319 +        bigSeed.resize(N);
320 +        register uint32 *s = &bigSeed[0];
321 +        register int i = N;
322 +        register bool success = true;
323 +        while( success && i-- )
324 +          success = fread( s++, sizeof(uint32), 1, urandom );
325 +        fclose(urandom);
326 +        if( success ) { return bigSeed; }
327 +      }
328    
329 <  // Was not successful, so use time() and clock() instead
329 >    // Was not successful, so use time() and clock() instead
330  
331 <  bigSeed.push_back(hash( time(NULL), clock()));
332 <  return bigSeed;
333 < }
331 >    bigSeed.push_back(hash( time(NULL), clock()));
332 >    return bigSeed;
333 >  }
334  
335  
336 < inline void MTRand::initialize( const uint32 seed )
337 < {
338 <        // Initialize generator state with seed
339 <        // See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier.
340 <        // In previous versions, most significant bits (MSBs) of the seed affect
341 <        // only MSBs of the state array.  Modified 9 Jan 2002 by Makoto Matsumoto.
342 <        register uint32 *s = state;
343 <        register uint32 *r = state;
344 <        register int i = 1;
345 <        *s++ = seed & 0xffffffffUL;
346 <        for( ; i < N; ++i )
347 <        {
348 <                *s++ = ( 1812433253UL * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffUL;
349 <                r++;
350 <        }
351 < }
336 >  inline void MTRand::initialize( const uint32 seed )
337 >  {
338 >    // Initialize generator state with seed
339 >    // See Knuth TAOCP Vol 2, 3rd Ed, p.106 for multiplier.
340 >    // In previous versions, most significant bits (MSBs) of the seed affect
341 >    // only MSBs of the state array.  Modified 9 Jan 2002 by Makoto Matsumoto.
342 >    register uint32 *s = state;
343 >    register uint32 *r = state;
344 >    register int i = 1;
345 >    *s++ = seed & 0xffffffffUL;
346 >    for( ; i < N; ++i )
347 >      {
348 >        *s++ = ( 1812433253UL * ( *r ^ (*r >> 30) ) + i ) & 0xffffffffUL;
349 >        r++;
350 >      }
351 >  }
352  
353  
354 < inline void MTRand::reload()
355 < {
356 <        // Generate N new values in state
357 <        // Made clearer and faster by Matthew Bellew (matthew.bellew@home.com)
358 <        register uint32 *p = state;
359 <        register int i;
360 <        for( i = N - M; i--; ++p )
361 <                *p = twist( p[M], p[0], p[1] );
362 <        for( i = M; --i; ++p )
363 <                *p = twist( p[M-N], p[0], p[1] );
364 <        *p = twist( p[M-N], p[0], state[0] );
354 >  inline void MTRand::reload()
355 >  {
356 >    // Generate N new values in state
357 >    // Made clearer and faster by Matthew Bellew (matthew.bellew@home.com)
358 >    register uint32 *p = state;
359 >    register int i;
360 >    for( i = N - M; i--; ++p )
361 >      *p = twist( p[M], p[0], p[1] );
362 >    for( i = M; --i; ++p )
363 >      *p = twist( p[M-N], p[0], p[1] );
364 >    *p = twist( p[M-N], p[0], state[0] );
365  
366 <        left = N, pNext = state;
367 < }
366 >    left = N, pNext = state;
367 >  }
368  
369  
370 < inline MTRand::uint32 MTRand::hash( time_t t, clock_t c )
371 < {
372 <        // Get a uint32 from t and c
373 <        // Better than uint32(x) in case x is floating point in [0,1]
374 <        // Based on code by Lawrence Kirby (fred@genesis.demon.co.uk)
370 >  inline MTRand::uint32 MTRand::hash( time_t t, clock_t c )
371 >  {
372 >    // Get a uint32 from t and c
373 >    // Better than uint32(x) in case x is floating point in [0,1]
374 >    // Based on code by Lawrence Kirby (fred@genesis.demon.co.uk)
375  
376 <        static uint32 differ = 0;  // guarantee time-based seeds will change
376 >    static uint32 differ = 0;  // guarantee time-based seeds will change
377  
378 <        uint32 h1 = 0;
379 <        unsigned char *p = (unsigned char *) &t;
380 <        for( size_t i = 0; i < sizeof(t); ++i )
381 <        {
382 <                h1 *= UCHAR_MAX + 2U;
383 <                h1 += p[i];
384 <        }
385 <        uint32 h2 = 0;
386 <        p = (unsigned char *) &c;
387 <        for( size_t j = 0; j < sizeof(c); ++j )
388 <        {
389 <                h2 *= UCHAR_MAX + 2U;
390 <                h2 += p[j];
391 <        }
392 <        return ( h1 + differ++ ) ^ h2;
393 < }
378 >    uint32 h1 = 0;
379 >    unsigned char *p = (unsigned char *) &t;
380 >    for( size_t i = 0; i < sizeof(t); ++i )
381 >      {
382 >        h1 *= UCHAR_MAX + 2U;
383 >        h1 += p[i];
384 >      }
385 >    uint32 h2 = 0;
386 >    p = (unsigned char *) &c;
387 >    for( size_t j = 0; j < sizeof(c); ++j )
388 >      {
389 >        h2 *= UCHAR_MAX + 2U;
390 >        h2 += p[j];
391 >      }
392 >    return ( h1 + differ++ ) ^ h2;
393 >  }
394  
395  
396 < inline void MTRand::save( uint32* saveArray ) const
397 < {
398 <        register uint32 *sa = saveArray;
399 <        register const uint32 *s = state;
400 <        register int i = N;
401 <        for( ; i--; *sa++ = *s++ ) {}
402 <        *sa = left;
403 < }
396 >  inline void MTRand::save( uint32* saveArray ) const
397 >  {
398 >    register uint32 *sa = saveArray;
399 >    register const uint32 *s = state;
400 >    register int i = N;
401 >    for( ; i--; *sa++ = *s++ ) {}
402 >    *sa = left;
403 >  }
404  
405  
406 < inline void MTRand::load( uint32 *const loadArray )
407 < {
408 <        register uint32 *s = state;
409 <        register uint32 *la = loadArray;
410 <        register int i = N;
411 <        for( ; i--; *s++ = *la++ ) {}
412 <        left = *la;
413 <        pNext = &state[N-left];
414 < }
406 >  inline void MTRand::load( uint32 *const loadArray )
407 >  {
408 >    register uint32 *s = state;
409 >    register uint32 *la = loadArray;
410 >    register int i = N;
411 >    for( ; i--; *s++ = *la++ ) {}
412 >    left = *la;
413 >    pNext = &state[N-left];
414 >  }
415  
416  
417 < inline std::ostream& operator<<( std::ostream& os, const MTRand& mtrand )
418 < {
419 <        register const MTRand::uint32 *s = mtrand.state;
420 <        register int i = mtrand.N;
421 <        for( ; i--; os << *s++ << "\t" ) {}
422 <        return os << mtrand.left;
423 < }
417 >  inline std::ostream& operator<<( std::ostream& os, const MTRand& mtrand )
418 >  {
419 >    register const MTRand::uint32 *s = mtrand.state;
420 >    register int i = mtrand.N;
421 >    for( ; i--; os << *s++ << "\t" ) {}
422 >    return os << mtrand.left;
423 >  }
424  
425  
426 < inline std::istream& operator>>( std::istream& is, MTRand& mtrand )
427 < {
428 <        register MTRand::uint32 *s = mtrand.state;
429 <        register int i = mtrand.N;
430 <        for( ; i--; is >> *s++ ) {}
431 <        is >> mtrand.left;
432 <        mtrand.pNext = &mtrand.state[mtrand.N-mtrand.left];
433 <        return is;
434 < }
426 >  inline std::istream& operator>>( std::istream& is, MTRand& mtrand )
427 >  {
428 >    register MTRand::uint32 *s = mtrand.state;
429 >    register int i = mtrand.N;
430 >    for( ; i--; is >> *s++ ) {}
431 >    is >> mtrand.left;
432 >    mtrand.pNext = &mtrand.state[mtrand.N-mtrand.left];
433 >    return is;
434 >  }
435  
436   }
437   #endif  // MERSENNETWISTER_H

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines