Hello experts
This question is shared with one of my research team.
We are dealing with an optimization problem in which the algorithm will choose the cross-section of the column (RC structure) between a lower and an upper bound (e.g., LB and UB).
We know that the obtained optimal values for the section can be for example 330mm.
Recently, we came across this phrase in a paper dealing with the same problem where the author stated that 'The column sections are square with dimensions of 250 mm × 250 mm to 1200 mm × 1200 mm, by a step of 50 mm'
Our concern is how to oblige the algorithm to choose 50mm for the next candidate within the design interval.
Anyone knows how to do it, please?
Dear Djedoui Nassim ,
To ensure that the optimization algorithm chooses a step size of 50mm within the design interval, you can incorporate a discretization constraint into the optimization problem. This constraint will restrict the possible values for the cross-section to a finite set of discrete values, with a fixed step size of 50mm.
One way to implement this constraint is to introduce a binary variable for each possible cross-section dimension, where the variable takes the value of 1 if that dimension is selected and 0 otherwise. Then, you can use a set of linear constraints to ensure that only one dimension is selected, and the selected dimension is a multiple of 50mm within the given design interval.
For example, if the design interval is [250mm, 1200mm], you can define the binary variable x_i for each possible dimension d_i within this interval, where d_i = 250mm + 50mm * (i-1) for i = 1, 2, ..., 19. Then, you can add the following set of constraints to the optimization problem:
- Only one dimension can be selected: Sum(x_i) = 1
- The selected dimension is within the design interval: Sum(d_i * x_i) >= LB and Sum(d_i * x_i)
Hi Djedoui Nassim
Did you see my answer to Djaafar's question?
Regards.
Hello
You can simply define your range, e.g. from 1 to ....
And in your code you can say
If: round(var)==1 》Sec C1
Elseif round(var)==2 》Sec C2
.
.
Good luck
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