Function PGAIntegerAlternatingEdgeCrossover

Function Documentation

void PGAIntegerAlternatingEdgeCrossover(PGAContext *ctx, int p1, int p2, int pop1, int c1, int c2, int pop2)

Perform Alternating Edge Crossover on two parent strings producing two children via side-effect.

Description

Note that this function is set in PGASetUp() as the crossover user function for the integer datatype when selecting partially mapped crossover.

The operation produces permutations of the integer genes of both parents. The result is a permutation again for both children.

Note that the original paper [GGRG85] mandates that the search starts with a random position. We start with a random position but keep the absolute position in the child (and don’t copy from the middle of the parent to the start of the child). This may make the crossover work for other problems than just TSP. From the paper it is unclear if edge reversals are possible, we allow them but prefer non-reversed egdes.

Example

Performs crossover on the two parent strings m and d, producing children s and b.

PGAContext *ctx;
int m, d, s, b;

...
PGAIntegerAlternatingEdgeCrossover
    (ctx, m, d, PGA_OLDPOP, s, b, PGA_NEWPOP);

Parameters:

  • ctx – context variable

  • p1 – the first parent string

  • p2 – the second parent string

  • pop1 – symbolic constant of the population containing string p1 and p2

  • c1 – the first child string

  • c2 – the second child string

  • pop2 – symbolic constant of the population to contain string c1 and c2

Returns:

c1 and c2 in population pop2 are modified by side-effect.