GA to solve N Queens

The puzzle - to put n Queens on an n*n chessboard so that none is in check. Normally this is solved using back tracking, but here a Genetic Algorithm is used.

You select the size of board and can see members of the population of possible solutions. The possible solution is the row of the queen in each column : shown as numbers below the board. The fitness of each solution is based on the number of non attacking pairs of Queens - the higher the better : also listed. If fitness is n*n-1 then there is a perfect solution.

If no solution, press Mutate or Crossover, and a new 'chld' is bred from one or two parents selected using a weighted roulette wheel (also shown). The random number used and the parent selected are shown on the wheel. The column used for CrossOver / Mutation is also shown.

If child is acceptable press Install and this child replaces the poorest member of the population.

Hint, Install if the fitness is better, and generally better to not install an existing solution.

User override is of the form Cabc meaning do Crossover of parents a and b at point c; Mabc where Mutate parent a moving queen in column b by c rows; or Ppabcd(etc) meaning parent p has queens in rows a,b,c,d,(etc). Enter then press DoIt.