Operation solver

Main > Reference Manual > Solver algorithm > Implementation details > Operation solver

Fixed time operation

Operation is asked for a quantity Q at the date D
Create an operation plan
If lead time constraints are enabled and the operation plan is planned in the past

Calculate the earliest date the operation can be completed
Return a promise with quantity 0 and the next ask date computed above

If capacity constraints are enabled

Loop until no capacity overloads are found
Loop over all loadplans
Ask the resource solver to check for overloads
If a capacity constraint is found, the resource solver will move the operation plan to an earlier date or resize it.
We then restart the loop over the loadplans
If the operation plan is found to be capacity infeasible
Return a promise with quantity 0

For each consuming flowplans

Ask the buffer for the planned quantity on the requested date.
If material constraints are enabled we update Qremaining and Dupdated.

Return the accumulated promise quantity

Time-per operation

The steps are very similar to the fixed_time operations, with the difference that the calculations for the feasible quantity is more complex.

Alternate operation

Operation is asked for a quantity Q at the date D
Remaining quantity = Q
Next ask date = infinite future
Loop through all alternate sub operations

If the alternate is not effective on the ask date, skip this alternate
Create top operation plan descriptor
Call Operation->ask(Remaining quantity, D)
If some quantity could be planned along the alternate
Check for material and capacity constraints on the top operation plan
Reduce the remaining quantity
Break out of the loop if the requested quantity is completely planned
Else
If the next ask date of the alternate is less than the current minimum, update the next ask date

If the total quantity planned over all alternates is less than the requested quantity

Repeat the loop over all alternate sub operations, but evaluate only alternates whose effectivity ends before the ask date

Return the planned quantity and the next ask date

Routing operation

Operation is asked for a quantity Q at the date D
Create the top operation plan
Check the flowplans and loadplans of the top operation plan
Initialize Q2 to Q and D2 to D
For all steps of the routing

Call operation->ask(Q2,D2)
Update Q2 if planned quantity < Q2
Update D2 with the operation time