Wednesday, November 3, 2021

Sahara

  It's an optimization problem: computer has to place the

three hospitals so that the cost (number of steps getting every household

 to the hospital) is at its lowest.


The simplest algorithm - hill-climbing - solves it in 11 steps.



Yet the algorithm might just find a local minimum. In a more complex situation ie given a

larger 'state-space' with more houses, , one might want to do better...


So begins the CS50 AI optimization lecture. Very timely, to my mind. I had just 

finished watching a video on plans to build solar farms in the Sahara.


https://youtu.be/62ASvupr8Zg


                                                         *     *     *

This is the gig: the computer moves a hospital up, down, sideways

and if one of these is more cost-effective, that one becomes the new

start position. When there are no more better choices, the program stops.

The difficulty is that one can get bottlenecked in a local minimum.



There are variations on the hill-climbing algorithm:




The example below is from a random restart(with maximum at 20). What came 

back was between 36 and 54.






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