producing items, BP2 made random decision
as to candidate rules in the grammar and the position of each derivation.
These decisions may also be controlled in "step computation" (see §12).
of random number
are predetermined in computers. This means that each time you run BP2 you get
the same sequence. If you run an improvisation immediately after starting BP2
you get the same "random" performance... Of course, if the "Autorandomize" butto
is checked on the upper "Settings" dialo
every piece is likely to differ from tyhe preceding one, but this may not still
not be the way you expect a machine to "improvise"!
are two ways of avoiding this. First, you may want to instruct BP2 to produce
anything you've never heard before. For this the random-sequence generato
should be reseeded with an arbitrary number, for instance a number computed
from the date/time information available inside the computer. Select "Randomiz
in the "Misc" menu. You get the little "Randomize" dialog as shown Fig.23.
The current random seed numbe
is always 1 when you start BP2, therefore default random sequences are identical.
random seed is saved in the "-se" setting file automatically loaded with each
"Reset" will restart the random generator with the current seed number, thus
producing again the same sequence of random numbers. Clicking "New see
will take an arbitrary number as a new seed and recalculate the sequence
accordingly. Now you get something really unpredictable.
way of playing with randomness is to type a seed and click "Reset". In this
way you select manually one among more than 65,000 sequences (because the seed
may be any number between 0 and 65535). If you get a remarkable result with a
given value of the seed number, you should note it down carefully or save it
along with the current settings (see the "File" menu).
is no certitude that every future version of Macintosh® will produce the
same random sequence starting from a given seed number. In addition, you must
keep in mind that if you make changes in the grammar (modifying or moving
rules) the sequence is likely to change. If you need more control on
productions, either modify the grammar (see for instance "Programmed grammars",
§11 infra, or control procedures, reference manual §8.1) or make
decisions by hand as shown §12 infra.