functions in random_et.i -

             kolmogorov(diam, r0, all=, orig=, seed=)  
             kolmogorov(diam, all=, orig=, seed=)  
 
     returns an array of random phases which follow Kolmogorov  law on  
     a square pupil of DIAM pixels per side with  a  Fried's parameter  
     equal to R0 (in pixels, default is to set R0=DIAM).   If  a Point  
     Spread Function is to  be  calculated  from  the  generated phase  
     screen, it should be conveniently sampled  (i.e.,  R0  greater or  
     equal 2 or 3 pixels).  
         The  algorithm  is  the  mid-point  method  of  R.G.    Lane,  
     A. Glindemann and J.C. Dainty (``Simulation of a Kolmogorov phase  
     screen'' in Waves in Random Media, 2, 209-224, 1992).  
         Keyword ORIG is a flag which  indicates  whether  or  not the  
     original method by Lane et al. should be used (default is  to use  
     the original algorithm).  
         Keyword ALL is a flag which indicates whether or not  all the  
     computed phase screen should be returned.  The  default behaviour  
     is to return the smallest array into which a pupil  with diameter  
     DIAM can fit.  The computed  phase  screen  is  a (2^N+1)*(2^N+1)  
     array.  
         Keyword SEED is a scalar between  0.0  and  1.0 non-inclusive  
     and is used to reinitialized the random sequence.  If SEED is out  
     of range, the sequence is reinitialized as when Yorick starts.  

             random_normal(dimemsion_list)  
 
     returns an array of normally distributed random double values with  
     the given DIMENSION_LIST (nil for a scalar result).  
     Keyword SEED is a scalar between 0.0 and 1.0 non-inclusive and is  
     used to reinitialized the random sequence. If SEED is out of range,  
     the sequence is reinitialized as when Yorick starts.  
     The algorithm follows the Box-Muller method (see Numerical Recipes  
     by Press et al.).  

             random_normal_prev= []  
 
     if not nil, is the previous value computed by random_normal.  

             random_poisson(mean)  
 
     returns an array of random double values which follow a Poisson law  
     of parameter MEAN (the output has the same geometry of the input).  
     Keyword SEED is a scalar between 0.0 and 1.0 non-inclusive and is  
     used to reinitialized the random sequence. If SEED is out of range,  
     the sequence is reinitialized as when Yorick starts.  
     The code is adapted from `POIDEV' an IDL routine by Wayne Landsman  
     and the algorithm is from Numerical Recipes by Press et al.  
       

             random_uniform(dimemsion_list, seed=)  
 
     returns an array of uniformly distributed random double values with  
     the given DIMENSION_LIST (nil for a scalar result).  
     Keyword SEED is a scalar between 0.0 and 1.0 non-inclusive and is  
     used to reinitialized the random sequence. If SEED is out of range,  
     the sequence is reinitialized as when Yorick starts.