# Problem with summary.nlsList()

Nathan Pace (nlpace@bigpace.med.utah.edu)
Tue, 06 Jan 1998 18:40:24 -0600

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This message is particularly addressed to those doing modeling with
nlsList(), nlme.nlsList(), and nlme() functions. Any insights would be
appreciated

I have created a list of nlsList objects using the nlsList() function.
I am using a 1 compartment, 1st order PK model equation for plasma drug
concentrations during and after a constant (zero order) drug infusion.

I have a data frame with 1992 observations on 65 individuals
(clusters). I create a parametrized version of the data frame to
include the start values.

The call to nlsList() finishes with convergence for 58 individuals and
no convergence for 7 individuals.

print(remi.nlsList.1)
\$"1":
Residual sum of squares : 1775.557
parameters:
Vd alpha
6.806844 0.5903246
formula: concentration ~ remi.func.1(infusion.rate, time, infusion.time,

Vd, al
47 observations

.
.
.

\$"61":
NULL

.
.
.

\$"65":
Residual sum of squares : 2394.812
parameters:
Vd alpha
7.201714 0.3836954
formula: concentration ~ remi.func.1(infusion.rate, time, infusion.time,

Vd, al
21 observations

attr(, "class"):
[1] "nlsList" "lmList"
attr(, "call"):
nlsList(formula = concentration ~ remi.func.1(infusion.rate, time,
infusion.time, Vd, alpha), data = remi.par.1, cluster = ~
subjectid,
control = list(maxiter = 100, minscale = 1e-05))

The call to summary.nlsList() fails with several lines of errors and
warnings.

> summary.nlsList(remi.nlsList.1)
Error in summary.nlsList: Missing value where logical needed:
if(all(unlist(lap)
. . .
1: Replacement length not a multiple of number of elements to replace
in: data[
1:ll] <- old
2: Replacement length not a multiple of number of elements to replace
in: data[
1:ll] <- old
3: Replacement length not a multiple of number of elements to replace
in: data[
1:ll] <- old
4: 42 missing values generated coercing from character to logical in:
all(unl\
ist(lapply(form.lst, function(form, first.form) ....
Dumped

```--
Nathan Leon Pace, M.D., Professor of Anesthesiology
University of Utah, Salt Lake City, Utah 84132
W: 801-581-6393                H: 801-467-2925
W: 801-581-4367 (FAX)          H: 801-467-0555 (FAX)
W: nlpace@bigpace.med.utah.edu H: nlpaces@sisna.com

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