JPH03263221A - Detection of recursive structure - Google Patents

Abstract

PURPOSE:To synthesize programs with a small calculation volume by applying a rule to description between set structures to generate description of relations between divided structures and deciding the conformity between them. CONSTITUTION:A rule which is not applied to a part of a directed graph at the time when the conditional structure is the part of the directed graph is taken out of a structure dividing rule holding part 103 with respect to the directed graph held in a structure description holding part 101, and divided structure description of the rule is merged in a directed graph in a divided structure description holding part 102 to update the directed graph in the holding part 102, and the processing is repeated. When there are no parts to which the rule is applied, it is discriminated whether a part which is not checked for conformity of the directed graph in the holding part 101 exists or not by a structure conformity discriminating means 104; and when it does not exist, detection of a recursive structure is recognized to terminate the processing. Thus, the calculation volume for structure division and struction conformity is reduced, and programs are synthesized with the small calculation quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recursive structure detection method, particularly to a recursion structure detection method used in a system for synthesizing programs.

[Conventional technology] Conventionally, in systems that synthesize programs,
When deriving program text from a program's declarative input/output specifications, detect recursive structures by expressing the input/output specifications as logical formulas and proving the logical formulas with a theorem prover using knowledge of programming and programming languages as axioms. Was.

[Problems to be Solved by the Invention] The conventional recursive structure detection method described above has the disadvantage that it is difficult to put it into practical use because a large amount of calculation is required for proof using a theorem prover.

The purpose of the present invention is to reduce the amount of calculation compared to conventional methods.
The purpose of this invention is to provide a recursive structure detection method that enables program synthesis with a small amount of calculation.

[Means for Solving the Problems 1] The recursive structure detection method of the present invention stores input descriptions of structures and relationships between structures in a structure description holding unit, and applies rules to the descriptions of the structures and relationships between structures. The structure after the division and the description between the structures obtained by applying the application are held in the divided structure description holding unit, and the description of the structure and the relationship between the structures after the division is applied to the input structure and the description of the relationship between the structures. structure matching determination means for storing a plurality of rules that associate each other in a structure division rule holding unit and determining whether or not two descriptions match regarding a given structure and a relationship between the structures; Generating a description from the description in the structure description holding unit to the splitting structure description holding unit using the rules stored in the splitting rule holding unit; and generating a description from the description in the structure description holding unit using the structure matching determination means. and control means for controlling determination of coincidence of descriptions in the divided structure description holding unit.

[For production]

FIG. 1 is a block diagram showing the configuration of the recursive structure detection method of the present invention.

In the present invention, structures and relationships between structures are described using a directed graph in which structures are nodes and relationships are links.

As initial data, the structure description holding unit 101 holds a digraph G that describes structures and relationships between structures, and the divided structure description holding unit 102 holds an empty digraph G0. Further, the structure division rule holding unit 103 stores a plurality of ordered pairs (G'
-0G'', ) (i=1. . . , N). However, the digraph GL, which is a component of the rule, is called a conditional structure, and the digraph G''l is called a division structure.

The condition of the conditional structure means the application condition of the rule, and means that if the directed graph of the conditional structure matches the part of the directed graph in the structure description holding unit, the rule may be applied. The split structure represents a partial digraph in the split structure description holding unit that corresponds to a conditional structure that matches a portion of the directed graph in the structure description holding unit. In this sense, rules indicate the correspondence between partially directed graphs. The word "partition" is used because (in a sense) a digraph with a conditional structure is divided into a digraph with a partitioned structure.

The control means 105 performs the following processing.

(1) For the digraph G held in the structure description holding unit 101, it is determined from the structure division rule holding unit 103 that the conditional structure GL is a part of the digraph G and the rule is not applied to that part. rules (GL3.G”,
).

(2) The digraph resulting from fusing the digraph G''m with the digraph G held in the split structure description holding unit 102 is set to Gma+, and the split structure description holding unit 102 is updated to hold the digraph Gk1.

(3) Directed graph G held in the structure description section 101
If there is a portion to which the rule has not been applied, the process returns to step (1) and repeats the same process; if not, the next step (4) is performed.

(4) Using the structure matching determination means 104, match the entire directed graph held in the structure description holding unit 101;
A partially directed graph in the partitioned structure description holding unit 102 is detected.

Next, the operation of the present invention will be explained using an example.

Assume now that the input/output specifications of the program to be synthesized are "a program that generates, for input list F, an output list H in which each element is the square of each element of list F."

FIG. 2(a) is a directed graph showing input/output specifications, including an input list F201 with a list structure, an output list H2O2 with a list structure, and a relationship 211 showing that each element corresponds to the element of its square. It becomes more. Also, in the structure division rule holding unit 103, Rule 8 "Divide a list into its first element and the remaining list" and Rule B "Divide a series of correspondence relations into the first relation and the remaining relations." There is a rule that says "do." FIG. 2(b) shows that rule A is applied to the partially directed graph (201), and rule A is applied to the partially directed graph (211).
) and rule A for the partially directed graph (202).
It is a directed graph generated as a result of applying the above, and it is understood that the l element 203, the list structure 204, the l element 205, the list structure 206, the square relation 212, and each element corresponds to its square element. The relationship 213 shown in FIG. Therefore, the structure matching determination means 104 determines the
It is detected that the structures of the directed graph (201, 211, 202) in a) and the partially directed graph (204, 213, 206) in FIG. 2(b) match.

From the above, it can be seen that the program with the input/output specifications shown in Figure 2(a) can be synthesized as having a recursive structure, and the partially directed graph (203, 21
2, 205), it becomes possible to synthesize all programs.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIGS. 3(a) and 3(b) are diagrams showing representations of nodes and links of a directed graph held by the structure description holding unit 101 and the divided structure description holding unit 102, respectively, in an embodiment of the recursive structure detection method of the present invention. , FIG. 4 is a diagram showing the expression of the rules stored in the structure division rule holding unit 103 of this embodiment, and FIG. 5 is a flowchart showing the processing of this embodiment.

A directed graph is represented by a set of nodes and links.
FIG. 3(a) is a frame representation of a node, which consists of an identifier slot for identifying the node and a structure type slot for indicating the type of structure. Also, Fig. 3(b)
is a frame representation of a link, with an identifier slot, a relationship type slot indicating the type of relationship, a relationship source node slot that holds the identifier of the source node of the relationship, and a relationship destination that holds the identifier of the destination node of the relationship. Consists of node slots. A structural partitioning rule, which is an ordered pair of directed graphs, is expressed as shown in FIG. 4 using a conditional structure description and a partitioning structure description, each of which is a set of nodes and links. The structure matching determination means 104 includes the structure description holding unit 1
It is detected whether the directed graph in 01 matches the partial directed graph in the partitioned structure description holding unit 102.

Next, the processing by the control means 1( ) 5 of this embodiment will be explained using FIG.

The program is started, and it is checked whether there is a rule in the structure division rule holding unit 103 whose conditional structure description matches a rule-unapplied part of the directed graph stored in the structure description holding unit 101 (step 501). , if the rule exists, it is extracted (step 502); if the rule does not exist, the process advances to step 504.

The division structure description of the rule retrieved in step 502 is merged with the digraph in the division structure description holding unit 102 to update the digraph in the division structure description holding unit 102 (step 503), and the process returns to step 501 to perform the same process. Repeatedly, proceeding to step 504, the structure matching determination means 1
04, the directed graph in the structure description holding unit 101 is checked to see if there is a part that has not been checked for a match. If there is no part, it is assumed that a recursive structure has been detected and the process ends (program synthesis is possible). Step 505 for extracting a partially directed graph; Check whether there is a matching portion from the partitioned structure description holding unit 102 for the extracted portion (Step 506); if found, return to Step 504 and repeat the same process; If no recursive structure is found, processing is terminated (program synthesis is not possible).

Effects of the Invention 1 As explained above, the present invention uses a directed graph to express the description of structures and the relationships between the structures, and applies rules to the description of the set structures and the relationships between the structures. By generating a description of the structure and the relationship between the structures and determining whether they match, the amount of calculation for structure partitioning and structure matching is relatively small compared to methods that use a theorem prover, etc., making it possible to program with less calculation. It has the effect of enabling synthesis.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the recursive structure detection method of the present invention, and Figures 2 (a) and (b) are diagrams showing a directed graph showing input/output specifications and a directed graph generated using rules for this, respectively. , FIGS. 3(a) and 3(b) are diagrams showing representations of nodes and links of a directed graph held by the structure description holding unit 101 and the divided structure description holding unit 102, respectively, in this embodiment, and FIG. A fifth diagram showing the expression of rules stored in the example structure division rule holding unit 103.
The figure is a flowchart showing the processing of this embodiment. DESCRIPTION OF SYMBOLS 101... Structure description holding part, 102... Division structure description holding part, 103... Structure division rule holding part, 104... Structure matching judgment means, 105... Control means, 201... Input List F, 202...Output list H1 203, 205...-Elements, 204 206...List structure, 501-506...Steps.

Claims (1)

[Claims] 1. In a system that performs program synthesis, a description of input structures and relationships between structures is held in a structure description holding unit, and rules are applied to the descriptions of the structures and relationships between structures. The obtained structure after division and descriptions between structures are retained in the division structure description holding unit, and the descriptions of the structures and relationships between structures after division are associated with the input descriptions of structures and relationships between structures. a structure matching determination means that stores a plurality of rules in a structure division rule holding unit and determines whether two descriptions of a given structure and the relationship between the structures match; generation of a description from the description in the structure description holding unit to the divided structure description holding unit using rules stored in the structure description holding unit; and generating a description between the description in the structure description holding unit and the split structure using the structure matching determination means A recursive structure detection method comprising a control means for determining whether a description in a description storage unit matches.