I am looking to add a cost calculator to my website for calculating the cost of shipping items. I need someone that is good with algorithms as what needs to be calculated is as the customer will select an item to ship, the calculator will automatically figure out what size box to ship the item in, then estimate the costs associated to that. As each item is added to be shipped the calculator will figure out how many items can fit in a package to ship and then figure out if multiple packages are required. This has to be done efficiently.
The algorithm that I am looking to use is (X ' X)-1 X ' y - so the programmer should be familiar with this algorithm and have experience in these calculations.