Search found 7 matches

by suprafluid
3 weeks ago
Forum: Modeling
Topic: Change of solution without changing code
Replies: 1
Views: 80

Change of solution without changing code

Hi everyone, The attached model determines a maximum power demand depending on velocities of cars. The quicker they drive, the longer must the distance be between them. The cars cannot exceed speed that would make the needed distance between cars larger than the overall track length. I calculate the...
by suprafluid
1 month ago
Forum: Syntax
Topic: Endogenous function in lag operation
Replies: 0
Views: 58

Endogenous function in lag operation

Hi everyone,

I want to use a lag operation in an equation which is dependent on another variable. I am not allowed to do that. Do you know of any workaround?

Code: Select all

[...] .. c(i,lc,t) =l= c(i,lc++step(i,t),t+1)
Many thanks,
supra
by suprafluid
1 month ago
Forum: Syntax
Topic: bounds on sum for looping through sets
Replies: 4
Views: 167

Re: bounds on sum for looping through sets

UPDATE 2: Found a working but not satisfying solution by hardcoding the number of lags that represent a minimum that I have to determine in advance. So I get sth like this: minDistance(lc,t) .. sum(i, c(i,lc-dMinlc,t) + c(i,lc-(dMinlc-1),t) + ... + c(i,lc,t) + ... + c(i,lc+dMinlc,t)) =l= 1 So I am s...
by suprafluid
1 month ago
Forum: Syntax
Topic: Summation with variable lower and upper bound
Replies: 4
Views: 214

Re: Summation with variable lower and upper bound

Hi Moritz,

could you find any solution to your question that you'd like to share? It feels like you have a similar problem to solve as I do as specified in my post "bounds on sum for looping through sets".

Best regards
supra
by suprafluid
1 month ago
Forum: Syntax
Topic: bounds on sum for looping through sets
Replies: 4
Views: 167

Re: bounds on sum for looping through sets

UPDATE: I tried further coming up with the following, still not working code (Error 125: Set is under control already): minDistance(lc,t) .. sum(i,sum(lc $ (ord(lc) ge ord(lc-dMinlc) and ord(lc) le ord(lc+dMinlc)),c(i,lc,t))) =l= 1 I replaced set l by set lc, just beacuse it is easier to distinguish...
by suprafluid
1 month ago
Forum: Syntax
Topic: bounds on sum for looping through sets
Replies: 4
Views: 167

bounds on sum for looping through sets

Hello everyone, it is me again, I have a second issue when modeling my application for the purpose of finding out the maximum power needed. My objects i are moving in a circle and need to keep a minimum distance dMin between each other at all timesteps t. I store if an object i is at a location l at...
by suprafluid
1 month ago
Forum: Syntax
Topic: Maximizing a maximum
Replies: 0
Views: 73

Maximizing a maximum

Hello everyone, I am developing a model for the purpose of finding out the maximum power needed for an application. The power p needed per timestep t depends on eight different objects i, hence p(i,t). I want to maximize the objective function P, which should be a single instance maximum of all powe...