erXover:

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   Er crossover takes two parents P1,P2 and performs edge recombination
   crossover on permutation strings. 

   Since version 7.
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   Form:
   [c1,c2] = er(p1,p2,bounds,ops)
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   ------
   Inputs
   ------  
   p1              the first parent ( [solution string function value] )
   p2              the second parent ( [solution string function value] )
   bounds          the bounds matrix for the solution space
   ops             Options matrix for simple crossover [gen #SimpXovers].

   -------
   Outputs
   -------
   c1
   c2

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