this page describes
Lavache is a composition generator for methods with a single hunt bell and for which inside bells do all the work.
The user selects a part end pattern, the number or number range of changes, and the intended calls. Up to four different calls (bob, single, ...) may be used and at indicated leads; calls will be admitted only where the coursing order of the back bells is preserved (but see Interludes below). If a three part on 456 is sought the program will accept either 645 or 564 as the first part end, and likewise for other patterns.
Where there is a degree of falsity, the user may try to steer the composition by preselecting certain leads. This has the effect of graying out leads false against these (see Feste) and so enhancing the prospect that the leads sought will be selected.
Chosen leads may be excluded. In Minor, the default action of the program is to ignore any callings with 65s at back stroke. (As with Feste the program is, strictly speaking, undefined for Minor. It does work, however.)
The user may specify an initial portion of the composition; the program will then attempt completion.
Counts can be kept of particular musical sequences, retaining only those compositions that meet some criterion of acceptability. Compositions may be sent to a file so that the machine may be left running indefinitely.
A powerful feature of the algorithm is the admissibility of 'Interludes'. An interlude is a section of the composition where the back bells are out of course. Up to nine types of interlude may be defined, the only condition being that the back bells must be back in course by the end of the interlude. These callings will then come within the scope of the search algorithm. A simple example would be 'in and 5ths' for Major.
Half lead calls may be allowed for by defining the containing lead to constitute an interlude - whether or not the back bells become parted. In the latter case, the interlude will be just one lead long.
The more calls and interludes allowed the slower the search will proceed. An indication is given of the proportion of the search completed.
This is a program of fair complexity; familiarity with TouchStone and Feste is recommended.
The material to be downloaded is in zip format. Click on the icon to initiate unzipping. You will be asked where to place the unzipped material; most simply, prepare a folder
for this purpose. There is a single folder lavatch, and a ReadMe text file. Click here to download Lavache. The suggested BRF donation is £15.