UPDATE NOTICE - THESE INSTRUCTIONS ARE NOT CURRENTLY CORRECT FOR THE MAINLINE OF THIS REPOSITORY
CURRENTLY THIS REPO IS NOT FULLY OPERATIONAL
To install Troll on your computer, you first need to install Moscow ML. There are instructions for this on the Moscow ML homepage (http://www.itu.dk/people/sestoft/mosml.html). When this accomplished, go to the Troll webpage (http://www.diku.dk/~torbenm/Troll/) and download the Troll.zip file. You have probably already done so if you are reading this file.
Unpack the zip-file in the directory where you want to install Troll and run one of the compile scripts: compile.sh for Linux/Unix and compile.bat for Windows. This will create a binary program called troll (Unixes) or troll.exe (Windows). The compiler will issue a warning about a non-standard feature used in the parser. This can safely be ignored.
When you have Troll installed, you can run it from a command line. You need to have a terminal or shell window open to do this.
Troll is invoked by the command troll. If run without arguments, it reads a Trollprogram from the terminal window (standard input) and prints a single random sample of the roll described by the Troll program. Example:
shell> troll 2d6 1 6 shell>
where is what you need to type to end terminal input on your system. For Unixes, this is ctrl-D and on Windows it is ctrl-Z.
Multisets are shown as sorted lists of numbers separated by spaces.
You can add a number to the troll command to get several samples:
shell> troll 5 2d6 1 4 5 5 2 6 2 5 4 6 shell>
Each sample is shown on a separate line. If you specify 0 as the number to the troll command, you get a probability distribution:
shell> troll 0
2d6
Value % = % >=
1 1 : 2.77777777778 100.0
1 2 : 5.55555555556 97.2222222222
1 3 : 5.55555555556 91.6666666667
1 4 : 5.55555555556 86.1111111111
1 5 : 5.55555555556 80.5555555556
1 6 : 5.55555555556 75.0
2 2 : 2.77777777778 69.4444444444
2 3 : 5.55555555556 66.6666666667
2 4 : 5.55555555556 61.1111111111
2 5 : 5.55555555556 55.5555555556
2 6 : 5.55555555556 50.0
3 3 : 2.77777777778 44.4444444444
3 4 : 5.55555555556 41.6666666667
3 5 : 5.55555555556 36.1111111111
3 6 : 5.55555555556 30.5555555556
4 4 : 2.77777777778 25.0
4 5 : 5.55555555556 22.2222222222
4 6 : 5.55555555556 16.6666666667
5 5 : 2.77777777778 11.1111111111
5 6 : 5.55555555556 8.33333333333
6 6 : 2.77777777778 2.77777777778
shell>
The probabilities are shown both for the result being equal to a value and for the result being at least a value. Lexicographic ordering of the multisets (as sorted lists) is used. By default, the probabilities are shown in percent, but if you add the -p option to the troll command, you get the probabilities as numbers between 0 and 1.
If the roll uses the accumulate loop or recursive functions, you can limit the iteration/recursion depth by specifying a negative number to the troll command. If you specify, for example, -5, you limit iterations and call depth to 5:
shell> troll -5
sum accumulate x:=d2 until x=2
Value % = % >=
2 : 50.0 96.875
3 : 25.0 46.875
4 : 12.5 21.875
5 : 6.25 9.375
6 : 3.125 3.125
Average = 2.75 Spread = 1.17260393996 Mean deviation = 0.8359375 shell>
Note that average, spread and mean deviation are calculated as all possible values are single numbers. The default limit is 12, so troll 0 and troll -12 are equivalent:
shell> troll 0
sum accumulate x:=d2 until x=2
Value % = % >=
2 : 50.0 99.9755859375
3 : 25.0 49.9755859375
4 : 12.5 24.9755859375
5 : 6.25 12.4755859375
6 : 3.125 6.2255859375
7 : 1.5625 3.1005859375
8 : 0.78125 1.5380859375
9 : 0.390625 0.7568359375
10 : 0.1953125 0.3662109375
11 : 0.09765625 0.1708984375
12 : 0.048828125 0.0732421875
13 : 0.0244140625 0.0244140625
Average = 2.99633789062 Spread = 1.40233352785 Mean deviation = 0.99706941843 shell>
You can also show the probability distribution as a histogram (in ASCII graphics) by using the -g option, where is the number of characters per percent in the histogram:
shell> troll 0 -g4
sum largest 3 4d6
Value 4.0 bars per %
3 :
4 : |
5 : |||
6 : ||||||
7 : ||||||||||||
8 : |||||||||||||||||||
9 : ||||||||||||||||||||||||||||
10 : ||||||||||||||||||||||||||||||||||||||
11 : ||||||||||||||||||||||||||||||||||||||||||||||
12 : ||||||||||||||||||||||||||||||||||||||||||||||||||||
13 : |||||||||||||||||||||||||||||||||||||||||||||||||||||
14 : |||||||||||||||||||||||||||||||||||||||||||||||||
15 : ||||||||||||||||||||||||||||||||||||||||
16 : |||||||||||||||||||||||||||||
17 : |||||||||||||||||
18 : ||||||
Average = 12.2445987654 Spread = 2.84684444531 Mean deviation = 2.31853947569 shell>
You can also take the Troll program from a file by specifying a file name on the command line. If the file d20stat.t contains the Troll program sum largest 3 4d6, the command line
troll 0 -g4 d20stat.t
will produce the same output as above. File names can not start with digits nor contain the = character.
You can also specify the value of a variable from the command line. If, for example, the file Nd6.t contains the Troll program sum N d6, the command
troll 0 Nd6.t N=5
will set N to 5 in the program, so you get the probability distribution for sum 5 d6.
See manual.pdf for a more detailed description of how to use Troll.