Divide N floats into M groups so that the sum of each group is as equal as possible?












0












$begingroup$


Given a list of N non-negative real numbers:



t = [2.99, 7.9, 24.58, ..., 3.1415, 40.4]



I want to partition the elements of $t$ into $M$ groups, $g_1$, $g_2$, ..., $g_M$, so that the sum of each group is as close as possible to $sum(t)/M$, i.e. minimizing the root mean square error:



Minimize: $sqrt{Sigma_i^M (sum(g_i) - sum(t)/M)^2 }$.



Do anyone know a close-to-optimal algorithm of doing this generally? Or do anyone know the name of this problem? (My google-fu failed me).



Background: $t$ represents time in seconds to run $N$ different tasks, and I want to schedule the $N$ tasks on $M$ different computers in such a way that all computers finish their tasks at the same time (or as close as possible).










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$endgroup$








  • 1




    $begingroup$
    Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
    $endgroup$
    – Hagen von Eitzen
    Dec 9 '18 at 17:53










  • $begingroup$
    This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
    $endgroup$
    – Ross Millikan
    Dec 9 '18 at 17:57










  • $begingroup$
    Can you confirm that $M$ is imposed ?
    $endgroup$
    – Jean Marie
    Dec 9 '18 at 18:07










  • $begingroup$
    @JeanMarie Yes, M is fix, for example "5", and not subject to change.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01










  • $begingroup$
    @HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01
















0












$begingroup$


Given a list of N non-negative real numbers:



t = [2.99, 7.9, 24.58, ..., 3.1415, 40.4]



I want to partition the elements of $t$ into $M$ groups, $g_1$, $g_2$, ..., $g_M$, so that the sum of each group is as close as possible to $sum(t)/M$, i.e. minimizing the root mean square error:



Minimize: $sqrt{Sigma_i^M (sum(g_i) - sum(t)/M)^2 }$.



Do anyone know a close-to-optimal algorithm of doing this generally? Or do anyone know the name of this problem? (My google-fu failed me).



Background: $t$ represents time in seconds to run $N$ different tasks, and I want to schedule the $N$ tasks on $M$ different computers in such a way that all computers finish their tasks at the same time (or as close as possible).










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
    $endgroup$
    – Hagen von Eitzen
    Dec 9 '18 at 17:53










  • $begingroup$
    This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
    $endgroup$
    – Ross Millikan
    Dec 9 '18 at 17:57










  • $begingroup$
    Can you confirm that $M$ is imposed ?
    $endgroup$
    – Jean Marie
    Dec 9 '18 at 18:07










  • $begingroup$
    @JeanMarie Yes, M is fix, for example "5", and not subject to change.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01










  • $begingroup$
    @HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01














0












0








0





$begingroup$


Given a list of N non-negative real numbers:



t = [2.99, 7.9, 24.58, ..., 3.1415, 40.4]



I want to partition the elements of $t$ into $M$ groups, $g_1$, $g_2$, ..., $g_M$, so that the sum of each group is as close as possible to $sum(t)/M$, i.e. minimizing the root mean square error:



Minimize: $sqrt{Sigma_i^M (sum(g_i) - sum(t)/M)^2 }$.



Do anyone know a close-to-optimal algorithm of doing this generally? Or do anyone know the name of this problem? (My google-fu failed me).



Background: $t$ represents time in seconds to run $N$ different tasks, and I want to schedule the $N$ tasks on $M$ different computers in such a way that all computers finish their tasks at the same time (or as close as possible).










share|cite|improve this question









$endgroup$




Given a list of N non-negative real numbers:



t = [2.99, 7.9, 24.58, ..., 3.1415, 40.4]



I want to partition the elements of $t$ into $M$ groups, $g_1$, $g_2$, ..., $g_M$, so that the sum of each group is as close as possible to $sum(t)/M$, i.e. minimizing the root mean square error:



Minimize: $sqrt{Sigma_i^M (sum(g_i) - sum(t)/M)^2 }$.



Do anyone know a close-to-optimal algorithm of doing this generally? Or do anyone know the name of this problem? (My google-fu failed me).



Background: $t$ represents time in seconds to run $N$ different tasks, and I want to schedule the $N$ tasks on $M$ different computers in such a way that all computers finish their tasks at the same time (or as close as possible).







optimization






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asked Dec 9 '18 at 17:43









PenlectPenlect

334




334








  • 1




    $begingroup$
    Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
    $endgroup$
    – Hagen von Eitzen
    Dec 9 '18 at 17:53










  • $begingroup$
    This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
    $endgroup$
    – Ross Millikan
    Dec 9 '18 at 17:57










  • $begingroup$
    Can you confirm that $M$ is imposed ?
    $endgroup$
    – Jean Marie
    Dec 9 '18 at 18:07










  • $begingroup$
    @JeanMarie Yes, M is fix, for example "5", and not subject to change.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01










  • $begingroup$
    @HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01














  • 1




    $begingroup$
    Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
    $endgroup$
    – Hagen von Eitzen
    Dec 9 '18 at 17:53










  • $begingroup$
    This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
    $endgroup$
    – Ross Millikan
    Dec 9 '18 at 17:57










  • $begingroup$
    Can you confirm that $M$ is imposed ?
    $endgroup$
    – Jean Marie
    Dec 9 '18 at 18:07










  • $begingroup$
    @JeanMarie Yes, M is fix, for example "5", and not subject to change.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01










  • $begingroup$
    @HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
    $endgroup$
    – Penlect
    Dec 9 '18 at 21:01








1




1




$begingroup$
Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
$endgroup$
– Hagen von Eitzen
Dec 9 '18 at 17:53




$begingroup$
Wouldn't your intended application suggest to minimize $max_isum(g_i)$ instead?
$endgroup$
– Hagen von Eitzen
Dec 9 '18 at 17:53












$begingroup$
This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
$endgroup$
– Ross Millikan
Dec 9 '18 at 17:57




$begingroup$
This looks like a variant on the bin packing problem to me. It is known to be NP-hard in the general case, but there are approaches that are pretty good.
$endgroup$
– Ross Millikan
Dec 9 '18 at 17:57












$begingroup$
Can you confirm that $M$ is imposed ?
$endgroup$
– Jean Marie
Dec 9 '18 at 18:07




$begingroup$
Can you confirm that $M$ is imposed ?
$endgroup$
– Jean Marie
Dec 9 '18 at 18:07












$begingroup$
@JeanMarie Yes, M is fix, for example "5", and not subject to change.
$endgroup$
– Penlect
Dec 9 '18 at 21:01




$begingroup$
@JeanMarie Yes, M is fix, for example "5", and not subject to change.
$endgroup$
– Penlect
Dec 9 '18 at 21:01












$begingroup$
@HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
$endgroup$
– Penlect
Dec 9 '18 at 21:01




$begingroup$
@HagenvonEitzen Good point, yes, minimizing your expression is also interesting. And now I'm curious if the optimal solution to that will automatically also be the optimal solution for the RMSE.
$endgroup$
– Penlect
Dec 9 '18 at 21:01










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