24 August 2004 10:18:39 AM

CVT_DATASET (C++ version)
  Generate a CVT dataset.

  Compiled on Aug 24 2004 at 07:47:40

  This program is meant to be used interactively.
  It is also possible to prepare a simple input
  file beforehand and use it in batch mode.

  The program requests input values from the user:

  * NDIM, the spatial dimension,
  * N, the number of points to generate,
  * SEED, a seed to use for random number generation,
  * INIT, initialize the points:
    ** file, read data from a file;
    ** GRID, by picking points from a grid;
    ** HALTON, from a Halton sequence;
    ** RANDOM, using FORTRAN RANDOM function;
    ** UNIFORM, using a simple uniform RNG;
  * IT_MAX, the maximum number of iterations.
  * IT_TOL, the iteration tolerance.
  * SAMPLE, how to conduct the sampling.
    ** GRID, by picking points from a grid;
    ** HALTON, from a Halton sequence;
    ** RANDOM, using FORTRAN RANDOM function;
    ** UNIFORM, using a simple uniform RNG;
  * SAMPLE_NUM, the number of sample points.
  * BATCH, the number of sample points to generate at one time.

  The program generates the data, writes it to the file

   cvt_NDIM_N.txt

  where "NDIM" and "N" are the numeric values specified
  by the user, and then asks the user for more input.

  To indicate that no further computations are
  desired, it is enough to input a nonsensical value,
  such as -1.
  *
 *
*  Ready to generate a new dataset:
 *
  *
  Enter NDIM, the spatial dimension:
  (0 or any negative value terminates execution).
  User input NDIM = 2

  Enter N, the number of points to generate:
  (0 or any negative value terminates execution).
  User input N = 15

  Enter SEED, a seed for the random number generator:
  (Any negative value terminates execution).
  User input SEED = 123456789

  INIT is the method of initializing the data:

  file     read data from a file;
  GRID     by picking points from a grid;
  HALTON   from a Halton sequence;
  RANDOM   using C++ RANDOM function;
  UNIFORM  using a simple uniform RNG;

  (A blank value terminates execution).

  Enter INIT:
  User input INIT = "initial11.txt".

  IT_MAX is the maximum number of iterations.

  An iteration carries out the following steps:
  * the Voronoi region associated with each
    generator is estimated by sampling;
  * the centroid of each Voronoi region is estimated.
  * the generator is replaced by the centroid.

  If "enough" sampling points are used,
  and "enough" iterations are taken, this process
  will converge.

  (A negative value terminates execution).

  Enter IT_MAX:
  User input IT_MAX = 40

  IT_TOL is the iteration tolerance.

  Each iteration replaces the generators by the
  centroids.  The L2 norm of the difference between
  these two sets of points is an indirect measure
  of convergence.

  If this L2 norm falls below IT_TOL, the iteration
  is presumed to have converged, and is terminated
  early.

  A zero value is acceptable, and simply means that
  early termination will not occur.

  (A negative value terminates execution).

  Enter IT_TOL:
  User input IT_TOL = 0

  SAMPLE is the method of sampling the region:

  GRID     by picking points from a grid;
  HALTON   from a Halton sequence;
  RANDOM   using C++ RANDOM function;
  UNIFORM  using a simple uniform RNG;

  (A blank value terminates execution).

  Enter SAMPLE:
  User input SAMPLE = "uniform".

  SAMPLE_NUM is the number of sample points.

  The Voronoi regions will be explored by generating
  SAMPLE_NUM points.  For each sample point, the
  nearest generator is found.  Using more points
  gives a better estimate of these regions.

  SAMPLE_NUM should be much larger than N, the
  number of generators.

  (A zero or negative value terminates execution.)

  Enter SAMPLE_NUM:
  User input SAMPLE_NUM = 10000

  BATCH is the number of sample points to create at one time.

  BATCH should be between 1 and SAMPLE_NUM.

  It is FASTER to set BATCH to SAMPLE_NUM;
  setting BATCH to 1 requires the least memory.

  (A zero or negative value terminates execution.)

  Enter BATCH:
  User input BATCH = 1000

  OUTPUT is a file in which to store the data.

  (A blank value terminates execution).

  Enter OUTPUT:
  User input OUTPUT = "cvt11.txt".

  Step  L2-Change

     1        0.682674
     2        0.341341
     3        0.288699
     4        0.214247
     5        0.179436
     6        0.153722
     7        0.115914
     8        0.122529
     9        0.116235
    10         0.11503
    11        0.114192
    12        0.114322
    13       0.0945578
    14       0.0815863
    15       0.0799948
    16         0.07013
    17       0.0822222
    18       0.0860385
    19       0.0540568
    20       0.0592706
    21       0.0713829
    22       0.0608356
    23       0.0770329
    24       0.0650965
    25       0.0622333
    26       0.0646596
    27        0.057146
    28       0.0676428
    29       0.0748537
    30       0.0605896
    31       0.0547824
    32       0.0719961
    33       0.0627877
    34       0.0718352
    35       0.0838971
    36        0.077353
    37       0.0777251
    38       0.0795602
    39       0.0619234
    40       0.0579335

  The data was written to the file "cvt11.txt
  *
 *
*  Ready to generate a new dataset:
 *
  *
  Enter NDIM, the spatial dimension:
  (0 or any negative value terminates execution).
  User input NDIM = -1

CVT_DATASET
  The input value of NDIM = -1
  is interpreted as a request for termination.
  Normal end of execution.

24 August 2004 10:18:40 AM