Decision Optimization

Decision Optimization

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  • 1.  cplex piecewise nonline function constraint

    Posted Wed November 30, 2022 11:08 AM
    Hi,

    I'm new to use CPLEX. I got a question about how to add a piecewise nonline constraintto my model. For example, I have 3 overlapped circles c1 to c3, I picked each some parts of each circle, i.e. arc, to form a convex region. Please see the figure below as an example:
    I want to constraint the x and y constrainted within the red shadow region. Any help will be appreciated! Thank you!

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    Qiuchen Qian
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    #DecisionOptimization


  • 2.  RE: cplex piecewise nonline function constraint

    Posted Wed November 30, 2022 12:14 PM
    Constraining points to be on or below the blue piecewise linear function is possible. Your shaded region seems to have boundaries composed of circular arcs, though, which cannot be modeled by piecewise linear functions. If that is not what you intended, perhaps you could provide a more detailed explanation or a more detailed diagram.

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    Paul Rubin
    Professor Emeritus
    Michigan State University
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  • 3.  RE: cplex piecewise nonline function constraint

    Posted Wed November 30, 2022 12:48 PM
    Edited by System Admin Fri January 20, 2023 04:31 PM
    Thanks for the reply, sorry I didn't make it clear. What I want is a nonlinear constraint that describes the red shade, which is formed with 3 arcs. The vertices of the convex region are marked as the red '+' sign. The blue point shows a feasible point (or solution) under this scenairo. Mathcatically, I have:
    (x - x1)2 + (y - y1)2 <= r12
    (x - x2)2 + (y - y2)2 <= r22
    (x - x3)2 + (y - y3)2 <= r32

    subject to the polar angles of corresponding arcs. Please see the figure below:
    Maybe it is a piecewise quadratic function when we put the feasible point on the arcs. 


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    Qiuchen Qian
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  • 4.  RE: cplex piecewise nonline function constraint

    Posted Wed November 30, 2022 02:04 PM
    If you want to limit solutions to the intersection of the three disks (the interiors of the three circles), just add all three quadratic inequalities as constraints.

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    Paul Rubin
    Professor Emeritus
    Michigan State University
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  • 5.  RE: cplex piecewise nonline function constraint

    Posted Wed November 30, 2022 02:49 PM
    I see, thank you!

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    Qiuchen Qian
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