PIES Research Project

PIES: Tool Suite Release 1 IEGenLib Examples

The following Python statements are examples on how to create sets and relations:

        >>> S1 = iegenlib.Set("{[s,i]: 0<=s && s<T && 0<=i && i<N}")
        >>> print S1
        
        >>> R1 = iegenlib.Relation("{[s,i]->[0,s,1,i,0]}")

The following Python statements are examples on how to apply operations (such as Apply, Union, Inverse, and Compose) between sets/relations:

        >>> S2 = R1.Apply(S1)           # Apply operation  #
        
        >>> S3 = iegenlib.Set("{[i,j]: 0<=i and i<n and 5<=j and j<m}")
        
        >>> S4 = iegenlib.Set("{[i,j]: 0<=i and i<n and m+5<=j and j<m+10}")
        
        >>> S4 = S3.Union(S4)           # Union operation #
        
        >>> R2 = iegenlib.Relation("{[i,j]->[ip,jp]: ip=f(i) and jp=2j}")
        
        >>> R3 = iegenlib.Relation("{[q,r]->[i,j]: i=q and j=r}")
        
        >>> R3 = R3.Compose(R2)         # Compose operation #
        
        >>> R2 = R2.Inverse()           # Inverse operation #
        
        >>> print R2                    # to print the resulting set/relation #
            { [ip, jp] -> [i, j] : ip - f(i) = 0 && 2 j - jp = 0 } 
                                        # The output of the print command #

Some examples that use function inverse declarations.

        >>> iegenlib.appendCurrEnv("f() = inverse f_inv()");

        >>> S5 = iegenlib.Set("{[i,j]:i=f(f_inv(j))}")
        >>> print "S5 = ", S5

        >>> R4 = iegenlib.Relation("{[i,j]->[ip,j]: ip=f(i)}")
        >>> print "R4 = ", R4

        >>> S6 = R4.Apply(S5)
        >>> print "S6 = ", S6

The user can obtain dot files for SparseConstraints objects of sets/relations from the IEGenlib Python Interface by using toDotString() methods. Python methods open(filename, mode) and write(item) can be used to open and write to the output file, as in the following examples:

         >>> S3 = iegenlib.Set("[n,m]->{[i,j]: 0<=i and i<n and 5<=j and j<m}")
         
         >>> file = open("S3.dot", 'w')
         
         >>> file.write(S3.toDotString())
         
         >>> file.close()