Persian Ney is one of the oldest musical instruments still in use. For more information read this website and this Wikipedia article.
This instrument is extremely simple, having a pipe-like structure. Traditionally, the constructors of this instrument look for natural canes in a canebrake that has certain length, given the frequency range they need to obtain from it. Larger instruments--sound pipes--produce lower frequencies and smaller ones producer higher ones.
The length of the pipe is not the only factor to make a Ney useful. Certain relationships must exist between its nodes, according to Masters of this instrument--more importantly Mr Kianinejad. The length of the nodes must decrease in an orderly fashion. That is, starting from top, subsequent nodes must keep decreasing in length. Further, it is better for the nodes to keep decreasing in diameter, too. Which would make the final pipe a cone.
While there a lot of quality instrumens produced, instruments that have all these properties are rare. That is in part due to the random growing nature of the plant. In a canebrake, probably a few branches would exibit these desirable properties naturally.
Given that after cutting the promising branches, they need to be stored for a couple of months, at least, for drainage, the construction becomes a risky business. Due to exposure to wind in the canebrake, branches become curvy, prompting the constructor to straighten them before finalizing the instrument. The shape of the final instrument must be a straight pipe. Unfortunately, at this stage, many of them get broken in the lack of enough care and experience. These problems have led to scarcity of quality instruments.
One solution is not using natural canes and instead using other materials, such as wood. This idea has led to successful alternative construction methods. However, among the community of Ney players and masters, Neys constructed via natural canes are more favorable.
It is unknown whether this is a subjective resistance towards materials other than natural cane or there are indeed differences in sound (e.g. timbre etc). No research has addressed this question so far.
The solution that is proposed in this study consist of using natural canes and reconfiguring the nodes. That is, instead of limiting oneself to the limited imperfect variety offered by the nature, a constructor can take any number of branches, cut their nodes, and reconfigure them to build perfect structures. The nodes can be connected again using proper stick, which is out of the scope of this paper.
This project develops a CSP-solver that acts as a design-aid tool hepling with the mix-and-match part, which turns out to be a combinatorial search problem, suitable for modeling as a Constraint Satisfaction Problem.
The desirable relationships between nodes mentioned above have been incorporated into several unary, binary, and higher level constraints in the CSP model.
Based on the nature of constraints, efficient procedures have been developed to establish binary and n-ary consistency. Hence, the solver conducts the search by maintaining the domains consistent, reducing the search space significantly. In fact, if solutions exists, the may search never backtrack, generating at most as many nodes as variables.
Some domains are defined as ranges of integer values and some are defined as a set of values. Furthermore, the solver adops conflict-directed backjumping.
Note: the entry point is main.py.