No Embedding Found Error on Structural Frustration example
I am going through the Structural Imbalance demo, here, and I wanted to know how big of a problem could be solved simply by increasing the size of the graph. In the example, we start with a 4-node fully connected graph. Increasing the graph size up to 65 nodes, takes less than 5 seconds to solve,
However, the script runs into a "No Embedding Found" error when I reach 66 nodes,
Why is that? My first guess is that a fully connected, 66-node graph contains too many parameters to be implemented onto the 2000 qubits chip, and there exists no embedding that can map this problem onto the chip. But I am not sure if this is correct, and having the correct explanation would be very much welcome.
Comments
You are correct! The theoretical maximum number of fully connected qubits on the D-Wave 2000Q is 65 qubits. Here's a link that discusses embedding fully connected graphs:
https://docs.dwavesys.com/docs/latest/handbook_embedding.html#embedding-complete-graphs
The following post has a lot of detailed information about embedding large QUBO problems onto the QPU.
https://support.dwavesys.com/hc/en-us/community/posts/360029426154-Solving-a-large-QUBO-problem-
I hope that's helpful. Please reach out if you have any more questions.
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