optim - setting a common contraint for multiple parameters












1















I a looking to set a common constraint to a subset of my parameters:



c2 <- 2
nFeatures = 6
W2 <- rep(1,nFeatures)
w2 <- W2/sum(W2)
fguess2 <- 0.3
startParms2 <- c(c2,fguess2,w2)
names(startParms2) <- c("c2", "fguess",
"w21","w22","w23","w24","w25","w26")


xout2 <- optim(par=startParms2, fn=rmsd,
data1=mydata2, method = "L-BFGS-B",
lower = rep(0,8),
upper = c(Inf,1,1,1,1,1,1,1))
print(xout2)


Currently, all 6 parameters belonging to the vector w2 are constrained to a individual maximum of 1.
What I would like to do is to constrain the sum of these 6 parameters to 1 (while the remaining 2 parameters keep their current constraints).










share|improve this question

























  • You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

    – Florian
    Nov 24 '18 at 18:15











  • in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

    – Ben Bolker
    Nov 26 '18 at 22:44


















1















I a looking to set a common constraint to a subset of my parameters:



c2 <- 2
nFeatures = 6
W2 <- rep(1,nFeatures)
w2 <- W2/sum(W2)
fguess2 <- 0.3
startParms2 <- c(c2,fguess2,w2)
names(startParms2) <- c("c2", "fguess",
"w21","w22","w23","w24","w25","w26")


xout2 <- optim(par=startParms2, fn=rmsd,
data1=mydata2, method = "L-BFGS-B",
lower = rep(0,8),
upper = c(Inf,1,1,1,1,1,1,1))
print(xout2)


Currently, all 6 parameters belonging to the vector w2 are constrained to a individual maximum of 1.
What I would like to do is to constrain the sum of these 6 parameters to 1 (while the remaining 2 parameters keep their current constraints).










share|improve this question

























  • You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

    – Florian
    Nov 24 '18 at 18:15











  • in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

    – Ben Bolker
    Nov 26 '18 at 22:44
















1












1








1








I a looking to set a common constraint to a subset of my parameters:



c2 <- 2
nFeatures = 6
W2 <- rep(1,nFeatures)
w2 <- W2/sum(W2)
fguess2 <- 0.3
startParms2 <- c(c2,fguess2,w2)
names(startParms2) <- c("c2", "fguess",
"w21","w22","w23","w24","w25","w26")


xout2 <- optim(par=startParms2, fn=rmsd,
data1=mydata2, method = "L-BFGS-B",
lower = rep(0,8),
upper = c(Inf,1,1,1,1,1,1,1))
print(xout2)


Currently, all 6 parameters belonging to the vector w2 are constrained to a individual maximum of 1.
What I would like to do is to constrain the sum of these 6 parameters to 1 (while the remaining 2 parameters keep their current constraints).










share|improve this question
















I a looking to set a common constraint to a subset of my parameters:



c2 <- 2
nFeatures = 6
W2 <- rep(1,nFeatures)
w2 <- W2/sum(W2)
fguess2 <- 0.3
startParms2 <- c(c2,fguess2,w2)
names(startParms2) <- c("c2", "fguess",
"w21","w22","w23","w24","w25","w26")


xout2 <- optim(par=startParms2, fn=rmsd,
data1=mydata2, method = "L-BFGS-B",
lower = rep(0,8),
upper = c(Inf,1,1,1,1,1,1,1))
print(xout2)


Currently, all 6 parameters belonging to the vector w2 are constrained to a individual maximum of 1.
What I would like to do is to constrain the sum of these 6 parameters to 1 (while the remaining 2 parameters keep their current constraints).







r optimization constraints






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 24 '18 at 18:18









Ben Bolker

133k11223311




133k11223311










asked Nov 24 '18 at 16:54









Moritz TruningerMoritz Truninger

91




91













  • You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

    – Florian
    Nov 24 '18 at 18:15











  • in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

    – Ben Bolker
    Nov 26 '18 at 22:44





















  • You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

    – Florian
    Nov 24 '18 at 18:15











  • in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

    – Ben Bolker
    Nov 26 '18 at 22:44



















You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

– Florian
Nov 24 '18 at 18:15





You can encode the constrain into the objective function. Then you will have to optimize only 5 parameters... - However, without a MCVE it is difficult to say more stackoverflow.com/help/mcve

– Florian
Nov 24 '18 at 18:15













in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

– Ben Bolker
Nov 26 '18 at 22:44







in principle you can use constrOptim(), but I suspect you really are trying to fit a composition parameter (all parameters bound in 0<p<1 and sum(p)==1), in which case you will be better off working with a softmax/Aitchison transformation

– Ben Bolker
Nov 26 '18 at 22:44














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