use old method to ensure same sequence for ARMA_RNG_ALT randn

2021-04-12 12:45:08 +10:00
parent 85b5cd7d54
commit a6b42aad6a
1 changed files with 7 additions and 1 deletions
@@ -489,7 +489,13 @@ struct arma_rng::randn
    {
    #if defined(ARMA_RNG_ALT)
      {
-      for(uword i=0; i < N; ++i)  { mem[i] = eT( arma_rng_alt::randn_val() ); }
+      // NOTE: old method to avoid regressions in user code that assumes specific sequence
+      
+      uword i, j;
+      
+      for(i=0, j=1; j < N; i+=2, j+=2)  { arma_rng_alt::randn_dual_val( mem[i], mem[j] ); }
+      
+      if(i < N)  { mem[i] = eT( arma_rng_alt::randn_val() ); }
      }
    #elif defined(ARMA_USE_EXTERN_RNG)
      {