Paul Bernal
2023-Aug-19 19:37 UTC
[R] Determining Starting Values for Model Parameters in Nonlinear Regression
Dear friends,
Hope you are all doing well and having a great weekend. I have data that
was collected on specific gravity and spectrophotometer analysis for 26
mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2 -
nitrodiphenylamine).
In the dataset, x1 = %NG, x2 = %TA, and x3 = %2 NDPA.
The response variable is the specific gravity, and the rest of the
variables are the predictors.
This is the dataset:
dput(mod14data_random)
structure(list(Mixture = c(17, 14, 5, 1, 11, 2, 16, 7, 19, 23,
20, 6, 13, 21, 3, 18, 15, 26, 8, 22), x1 = c(69.98, 72.5, 77.6,
79.98, 74.98, 80.06, 69.98, 77.34, 69.99, 67.49, 67.51, 77.63,
72.5, 67.5, 80.1, 69.99, 72.49, 64.99, 75.02, 67.48), x2 = c(29,
25.48, 21.38, 19.85, 22, 18.91, 29.99, 19.65, 26.99, 29.49, 32.47,
20.35, 26.48, 31.47, 16.87, 27.99, 24.49, 31.99, 24.96, 30.5),
x3 = c(1, 2, 1, 0, 3, 1, 0, 2.99, 3, 3, 0, 2, 1, 1, 3, 2,
3, 3, 0, 2), y = c(1.4287, 1.4426, 1.4677, 1.4774, 1.4565,
1.4807, 1.4279, 1.4684, 1.4301, 1.4188, 1.4157, 1.4686, 1.4414,
1.4172, 1.4829, 1.4291, 1.4438, 1.4068, 1.4524, 1.4183)), row.names c(NA,
-20L), class = "data.frame")
I need to determine starting (initial) values for the model parameters for
this nonlinear regression model, any ideas on how to accomplish this using
R?
Any help and/or guidance will be greatly appreciated.
Thanks, beforehand, for your valuable and kindness.
Best regards,
Paul
[[alternative HTML version deleted]]
Bert Gunter
2023-Aug-19 19:56 UTC
[R] Determining Starting Values for Model Parameters in Nonlinear Regression
" need to determine starting (initial) values for the model parameters for this nonlinear regression model," ... what nonlinear regression model? Did html get stripped? -- Bert On Sat, Aug 19, 2023 at 12:38?PM Paul Bernal <paulbernal07 at gmail.com> wrote:> Dear friends, > > Hope you are all doing well and having a great weekend. I have data that > was collected on specific gravity and spectrophotometer analysis for 26 > mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2 - > nitrodiphenylamine). > > In the dataset, x1 = %NG, x2 = %TA, and x3 = %2 NDPA. > > The response variable is the specific gravity, and the rest of the > variables are the predictors. > > This is the dataset: > dput(mod14data_random) > structure(list(Mixture = c(17, 14, 5, 1, 11, 2, 16, 7, 19, 23, > 20, 6, 13, 21, 3, 18, 15, 26, 8, 22), x1 = c(69.98, 72.5, 77.6, > 79.98, 74.98, 80.06, 69.98, 77.34, 69.99, 67.49, 67.51, 77.63, > 72.5, 67.5, 80.1, 69.99, 72.49, 64.99, 75.02, 67.48), x2 = c(29, > 25.48, 21.38, 19.85, 22, 18.91, 29.99, 19.65, 26.99, 29.49, 32.47, > 20.35, 26.48, 31.47, 16.87, 27.99, 24.49, 31.99, 24.96, 30.5), > x3 = c(1, 2, 1, 0, 3, 1, 0, 2.99, 3, 3, 0, 2, 1, 1, 3, 2, > 3, 3, 0, 2), y = c(1.4287, 1.4426, 1.4677, 1.4774, 1.4565, > 1.4807, 1.4279, 1.4684, 1.4301, 1.4188, 1.4157, 1.4686, 1.4414, > 1.4172, 1.4829, 1.4291, 1.4438, 1.4068, 1.4524, 1.4183)), row.names > c(NA, > -20L), class = "data.frame") > > I need to determine starting (initial) values for the model parameters for > this nonlinear regression model, any ideas on how to accomplish this using > R? > > Any help and/or guidance will be greatly appreciated. > > Thanks, beforehand, for your valuable and kindness. > > Best regards, > Paul > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]