i have used a composition tool called compose, programmed in lisp, to make all my compositions
since 2003.
this text outline the organization of this composition tool.

the formal compositional work take place in something i call a proportional space.

the proportional space is a serie of units.

all units have a length of one.

the proportional space can be divided into smaller spaces called fields.

a field has a length of at least one unit.

the total number of units that constitute a proportional space is called the resolution of the proportional space.

every field in a proportional space correspond to a sound or a silence in the score.

the sound or silence objects in a score is are represented by one or more score symboles.

the score symbols are either notes or rests.

the notes and pauses does not correspond to the fields in the proportional space.

a field can be represented in a score by several notes, and even in advanced cases by complex structures made of combinations of notes and pauses.
but it remains a single sound or silence.

there is no correspondence between the number of units in a field and the number of notes in the corresponding sound or silence in the score.

the score structure is made of sections, partial sections, measures and partial measures.

a partial measure correspond to a conductor beat.

every measure have a measure time signature.

every partial measure has a partial measure time signature.

every measure has at least one partial measure.
example: a 6/8 measure beaten on every dotted quaver is then a measure with a measure time signature of 6/8, made of two partial measures with a partial measure time signature of 3/8.

there can be several partial measure time signatures in one measure.

to be able to work in the proportional space i first need to know its resolution.

to know the resolution of a proportional space i have to construct that resolution.
this is done by making a nominal score.

a nominal score is an empty score where i have decided how many nominal objects it can be in every partial measure.

the nominal objects in a partial measure are of the same length.

the number of nominal objects determine the nominal resolution of that partial measure.

a nominal object correspond to one unit in the proportional space.

if i count all the nominal objects in a nominal score i will have the total number of units of the proportional space.

thus, the total number of nominal objects in the nominal score corresponds to the resolution of the proportional space.

once I have the resolution of the proportional space i can start the formal compositional work.

the temporal aspect of the formal compositional work is to divide the proportional space into nested fields.

once these divisions are made the proportional space is now organized in a hierarchical content (that correspond closely to the "contenu formel" of G. G. Granger:
formes opérations objets).

the bottom field in a hierarchical content at a given position is the active field.

an active field can be either a sound or a silence.

once i have the hierarchical content I can ask for its active fields.

once i have the active fields i can now lay out them on the nominal score.

i now have the raw score of the composition.

once i have the raw score the rhythmical structure is subject to a extended series of transformations in order to have the final rhythmical structure.

these transformations now take place on the score structure and is no longer related to the proportional space method.
i am thus changing to another set of rules.

when i have the final rhythmical structure I have the final raw score.
this is how far the composition tool take the structures of the composition.

all transformations made in the score after the production of the final raw score is made by hand.
paris, le 3 mars 2012
