Help implementing a weird model notation

回答済み

Lorenz Wagner

2023年12月03日 08:48

• 
• 
• 

Hey guys, I recently came across this model notation and I am having a hard time understanding and implementing it in Gurobi. [\\sum_{i,t:i.GG=1\wedge i.O=b}^{}x_{jit}\ge5 \forall j,b\] How do I "understand" the sum? Do the equations have to be fulfilled for both inidzes or only for t? My try looks like this: for j in J: for b in B: model.addConstr(gp.quicksum(x[j,i,t] for t in T if GG[i] == 1 and O[i] == b for i in I if GG[I] == 1 and O[I] == b) <= 5)

関連

• Python

0

• 正式なコメント

  

  Simranjit Kaur

  • Gurobi Staff

  2026年11月13日 01:33

  This post is more than two years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support.
• 

  Simranjit Kaur

  • Gurobi Staff

  2023年12月04日 02:15 編集済み

  Hi Lorenz,

  The logical operator \(\wedge\) represents conjunction, i.e., the and condition. So, the expression \(\sum_{i,t:i.GG=1\wedge i.O=b}\) means summing over i,t such that i.CG=1 and i.O=b. There are no checks for the index t in this condition.

  The constraint \[\sum_{i,t:i.GG=1\wedge i.O=b}x_{jit} \geq 5 \quad \forall j,b \] can be modelled as

  m.addConstrs((gp.quicksum(x[j,i,t] for i in I for t in T if GG[i] == 1 and O[i] == b) >= 5 for j in J for b in B), name="test")

  Best regards,
  Simran

  0

投稿コメントは受け付けていません。