Zohar Levi

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Activity overview

Latest activity by Zohar Levi

  • Zohar Levi commented,

    1. Community
    2. Algorithms
    3. Limit solutions for an LP

    It works, thanks.

  • Zohar Levi commented,

    1. Community
    2. Other
    3. cookie for a day

    It's already on, it fills the user/pass for me, and I need to press the button. But again, I prefer not to go through an extra login page each time: - get to the thread page, press sign in - wait f...

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    • Zohar Levi
    • Edited
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  • Zohar Levi commented,

    1. Community
    2. Programming
    3. linprog in c++

    The C interface supports CSC sparse rep, which should do the trick (c/c++ are all the same).  About a working example. I have a 3M X 30M matrix, with ~10 nnz in a row. If you use the addTerms in a ...

  • Zohar Levi commented,

    1. Community
    2. Other
    3. cookie for a day

    I tried both chrome and firefox. When I enter the thread url, it doesn't recognize me in both. If I want to leave a comment, then it suggests that I log in. I click the login: firefox: it refreshes...

  • Zohar Levi commented,

    1. Community
    2. Programming
    3. linprog in c++

    Using addTerms instead of += to add one term at the time cut the time by half, but not in an order of magnitude (e.g. from 2sec to 1sec, instead of 0.02sec). addTerms of all eq terms didn't make mu...

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    • Zohar Levi
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  • Zohar Levi commented,

    1. Community
    2. Algorithms
    3. LP with only equality constraints

    I naively thought that it's just a matter of solving a linear system of equalities, which usually takes under a second rather than a minute (using packages such mldivide, pardiso, umfpack). However...

  • Zohar Levi created a post,

    LP with only equality constraints

    Answered
    1. Community
    2. Algorithms

    How do I optimize it efficiently? Gurobi treats it as a standard LP (runs barrier/simplex). Update: I'm not sure about my expectation anymore. The problem is min c'x s.t. Ax=b. The KKT system is un...

    • Zohar Levi
    • Edited
    • 2 followers
    • 2 comments
    • 0 votes

  • Zohar Levi created a post,

    cookie for a day

    Answered
    1. Community
    2. Other

    It seems that the site remembers my login only for a day and requests it afterwards. Said login go smoothly when I reply to a message, and I need to do it a couple of times until it "gets me." The ...

    • Zohar Levi
    • 3 followers
    • 4 comments
    • 0 votes

  • Zohar Levi commented,

    1. Community
    2. Programming
    3. warm start LP solver in matlab

    I missed that, thanks.

  • Zohar Levi commented,

    1. Community
    2. Programming
    3. linprog in c++

    The mechanism for adding constraints is incredibly slow. Summing the matrix coeff takes 0.02sec. Gurobi adding constraints takes 7sec.  Gurobi optimizing the model takes 5sec. GRBEnv genv;GRBModel ...

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    • Zohar Levi
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