min z under these constrains












0












$begingroup$


$$min_{x,z} { z : z geq x^TA_{i}x ; (i=1,ldots,k), ; x^Tx=1}$$
$x$ is a vector and $A_{i}, i=1,2,...k $ are given matrixes










share|cite|improve this question











$endgroup$












  • $begingroup$
    Thank you for considering this problem. I am curious about the reason about the hardness. THX
    $endgroup$
    – Vida
    Jan 7 at 1:31










  • $begingroup$
    $x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
    $endgroup$
    – LinAlg
    Jan 7 at 1:50










  • $begingroup$
    Thank you so much for the valuable information. I really need to reconsider the problem.
    $endgroup$
    – Vida
    Jan 7 at 3:00
















0












$begingroup$


$$min_{x,z} { z : z geq x^TA_{i}x ; (i=1,ldots,k), ; x^Tx=1}$$
$x$ is a vector and $A_{i}, i=1,2,...k $ are given matrixes










share|cite|improve this question











$endgroup$












  • $begingroup$
    Thank you for considering this problem. I am curious about the reason about the hardness. THX
    $endgroup$
    – Vida
    Jan 7 at 1:31










  • $begingroup$
    $x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
    $endgroup$
    – LinAlg
    Jan 7 at 1:50










  • $begingroup$
    Thank you so much for the valuable information. I really need to reconsider the problem.
    $endgroup$
    – Vida
    Jan 7 at 3:00














0












0








0





$begingroup$


$$min_{x,z} { z : z geq x^TA_{i}x ; (i=1,ldots,k), ; x^Tx=1}$$
$x$ is a vector and $A_{i}, i=1,2,...k $ are given matrixes










share|cite|improve this question











$endgroup$




$$min_{x,z} { z : z geq x^TA_{i}x ; (i=1,ldots,k), ; x^Tx=1}$$
$x$ is a vector and $A_{i}, i=1,2,...k $ are given matrixes







linear-algebra optimization






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 7 at 1:47









LinAlg

9,0111521




9,0111521










asked Jan 6 at 18:37









VidaVida

12




12












  • $begingroup$
    Thank you for considering this problem. I am curious about the reason about the hardness. THX
    $endgroup$
    – Vida
    Jan 7 at 1:31










  • $begingroup$
    $x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
    $endgroup$
    – LinAlg
    Jan 7 at 1:50










  • $begingroup$
    Thank you so much for the valuable information. I really need to reconsider the problem.
    $endgroup$
    – Vida
    Jan 7 at 3:00


















  • $begingroup$
    Thank you for considering this problem. I am curious about the reason about the hardness. THX
    $endgroup$
    – Vida
    Jan 7 at 1:31










  • $begingroup$
    $x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
    $endgroup$
    – LinAlg
    Jan 7 at 1:50










  • $begingroup$
    Thank you so much for the valuable information. I really need to reconsider the problem.
    $endgroup$
    – Vida
    Jan 7 at 3:00
















$begingroup$
Thank you for considering this problem. I am curious about the reason about the hardness. THX
$endgroup$
– Vida
Jan 7 at 1:31




$begingroup$
Thank you for considering this problem. I am curious about the reason about the hardness. THX
$endgroup$
– Vida
Jan 7 at 1:31












$begingroup$
$x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
$endgroup$
– LinAlg
Jan 7 at 1:50




$begingroup$
$x^Tx=1$ is a nonconvex constraint, and very little information is given about $A_i$. The case $k=1$ is easy via the S-lemma. If $A_i$ are positive semidefinite you can write it as $max{x^Tx : x^TA_ixleq t}$ and solve it for different values of $t$ until the optimal objective value is $1$. CPLEX and Gurobi can now optimize nonconvex quadratic objectives over a convex quadratic domain.
$endgroup$
– LinAlg
Jan 7 at 1:50












$begingroup$
Thank you so much for the valuable information. I really need to reconsider the problem.
$endgroup$
– Vida
Jan 7 at 3:00




$begingroup$
Thank you so much for the valuable information. I really need to reconsider the problem.
$endgroup$
– Vida
Jan 7 at 3:00










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