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12 | 12 | # utesch@aut.tu-freiberg.de * Freiberg, Germany * |
13 | 13 | #*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= |
14 | 14 |
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15 | | -# this file should be '$PGDATA/pg_geqo', but it doesn't have |
16 | | -# to exist |
| 15 | +# To make this file do something, copy it to '$PGDATA/pg_geqo' |
| 16 | +# and edit parameters to taste. |
| 17 | +# If '$PGDATA/pg_geqo' doesn't exist, the system will use default parameters. |
| 18 | +# The file is re-read for every GEQO optimization, if it does exist. |
17 | 19 |
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18 | 20 | # comment character is '#' |
19 | 21 | # |
20 | 22 | # separator between recognized tag and possible value |
21 | 23 | # must be white space |
22 | 24 |
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23 | | -# qs: means query size, which is the number of relations |
| 25 | +# QS: means query size, which is the number of relations |
24 | 26 | # contained in a query |
25 | 27 |
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26 | 28 | #=================+===================+=============================+ |
27 | 29 | # RECOGNIZED TAGS | POSSIBLE VALUES | DEFAULTS | |
28 | 30 | #=================+===================+=============================+ |
29 | | -# 'Pool_Size' | positive int | 2^(qs+1) | |
| 31 | +# 'Pool_Size' | positive int | 2^(QS+1), but not less than | |
| 32 | +# | | 128 nor more than 1024. | |
30 | 33 | #-----------------+-------------------+-----------------------------+ |
31 | 34 | # 'Effort' | [low,medium,high] | medium | |
32 | 35 | #-----------------+-------------------+-----------------------------+ |
33 | | -# 'Generations' | positive int | 'Effort' * log2('Pool_Size')| |
| 36 | +# 'Generations' | positive int | Effort * log2(Pool_Size) | |
34 | 37 | #-----------------+-------------------+-----------------------------+ |
35 | | -# 'Selection_Bias'| [1.50; 2.00] | 2.0 | |
| 38 | +# 'Selection_Bias'| [1.50 .. 2.00] | 2.0 | |
36 | 39 | #-----------------+-------------------+-----------------------------+ |
37 | 40 | # 'Random_Seed' | positive long | time(NULL) | |
38 | 41 | #=================+===================+=============================+ |
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41 | 44 | # It gives us the number of individuals within one population. |
42 | 45 | # |
43 | 46 | # 'Effort' 'low' means integer value of 1, 'medium' 40, and 'high' 80. |
| 47 | +# Note: Effort is *only* used to derive a default value for Generations |
| 48 | +# --- if you specify Generations then Effort does not matter. |
44 | 49 | # |
45 | | -# 'Generations' gives us the stopping criterion for the number |
46 | | -# of iterations within the genetic algorithm. |
| 50 | +# 'Generations' specifies the number of iterations in the genetic algorithm. |
| 51 | +# |
| 52 | +# GEQO runtime is roughly proportional to Pool_Size + Generations. |
47 | 53 | # |
48 | 54 | # 'Selection_Bias' gives us the selective pressure within the |
49 | 55 | # population. |
50 | 56 | # |
51 | 57 | # 'Random_Seed' is the random seed for the random() function. |
52 | | -# You don't have to set it. |
| 58 | +# You don't have to set it. If you do set it, then successive GEQO |
| 59 | +# runs will produce repeatable results, whereas if you don't set it |
| 60 | +# there will be some randomness in the results... |
53 | 61 |
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54 | 62 | # All parameters will be computed within the GEQO module when they |
55 | 63 | # are not set in the pg_geqo file. |
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