Factoring

1. Use the Dwave Ocean tools to (A) try their factorization example under a simulator and then (B) on the Dwave 2000Q system.
   • PART A: Install the Ocean tools. For me, it's simple:

     	pip install --user dwave-ocean-sdk
           

   • Download the factoring example:

     	git clone https://github.com/dwavesystems/factoring-demo.git
           

   • Consult the following files:

     	factoring-demo/demo.py
     	factoring-demo/factoring/interfaces.py
     	https://github.com/dwavesystems/dwavebinarycsp/blob/master/dwavebinarycsp/factories/csp/circuits.py
           

     and read the factoring paper, which explains how to express factoring as a binary CSP.
   • Modify demo.py and interfaces.py to run it in simulation mode to factor the number 42: python demo.py
   • Verify that your results are correct.
   • Hints:
     • Look at Constrained Scheduling and change interfaces.py to "solve classically".
     • use an ExactSolver() instead of DWaveSampler()
     • You will neither need embeddings nor kwargs (for sampling), nor any unembedding, nor client.close operations
   • PART B: Sign up for a Dwave leap account.
   • Once you have it, take a look at the factoring example and check out "More Information" for each page, but don't run it in the final step.
   • Modify interfaces.py to run it on the Dwave hardware, use 4 bits for each factor and 8 bits for the product. Then factor the number 26.
   • Modify demo.py and interfaces.py to run it in hardware mode.
   • Verify that your results are correct.
   • Hints:
     • Look at Constrained Scheduling and change interfaces.py to solve "on a D-Wave System".
     • obtain the API token from your Dashboard
     • use DWaveSampler(endpoint='https://cloud.dwavesys.com/sapi', token='your-Token-here', solver = 'DW_2000Q_6') #used to be DW_2000Q_2
     • Change the number of reads to 500 (more than 50 samples needed)
     • Change the output to be 8 bits (p0..p7) and inputs to be 4 bits (a0..a3, b0..b3).
     • Change the multiplication_circuit to operate on 4 bits.
     • Modify demo.py to invoke factor with a 2nd parameter of False to indicate that no prior embedding exists.

   As part of this exercise, you should create the following files: interface-sim.py, demo-sim.py, output-sim.txt, interface-hw.py, demo-hw.py, output-hw.txt