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Transport-for-the-North / caf.distribute

https://cafdistribute.readthedocs.io/en/stable/
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4-D constraint #20

Open isaac-tfn opened 9 months ago

isaac-tfn commented 9 months ago

Add constraints on sector to sector movements on top of zone to zone. This would likely be a relatively simple addition to the furnessing process

nhannguyen2212 commented 9 months ago

Steps:

  1. user defined sectoral constraints (e.g. LADs, county, GOR) where we think we have confidence in the data (based on observed movements, NTS etc.) Obs[I,J] at sector pair [I,J]

  2. within the Furness function- Calculate output matrix from applying the gravity model T[i,j]

    • Compress the matrix T[i,j] to sector Syn[I,J] = SumT[i,j] over [I,J]
    • Calculate sectoral adjustment K[I,J] = Obs[I,J] / Syn[I,J] if there is confidence, else K[I,J] = 1
    • Apply K[I,J] to the Furness function T[i,j] = A[i]B[j]K[I,J]O[i]D[j]*f(C[i,j])

  3. The application of the K[I,J] can be undertaken within the Furness (above) or after the original Furness has finished. The former would take longer to run but hopefully yields better outcome. Need testing two methods to decide which one is better