f it produces an error: singular gradient matrix at initial parameter estimates.

You are watching: Singular gradient matrix at initial parameter estimates

The result is roughly a = 1.1466, b = 0.6415, so there shouldn"t be a problem with intial parameter estimates as I have defined them as a=1, b=0.5.

I have read in other topics that it is convenient to modify the curve. I was thinking about something like log y=log a *(b^x), but I don"t know how to deal with function specification. Any idea?


r curve-fitting nls
Share
Improve this question
Follow
edited Feb 17 "14 at 0:44
Vochmelka
asked Feb 16 "14 at 18:44
*

VochmelkaVochmelka
19911 silver badge88 bronze badges
2
Add a comment |

1 Answer 1


Active Oldest Votes
7
I will expand my comment into an answer.

If I use the following:

y or

(m I obtain:

As for automatically generating starting values, I am not familiar with a procedure to do that. One method I have read about is to simulate curves and use starting values that generate a curve that appears to approximate your data.

Here is the plot generated using the above parameter estimates using the following code. I admit that maybe the lower right portion of the line could fit a little better:

setwd("c:/users/mmiller21/simple R programs/")jpeg(filename = "nlr.plot.jpeg")plot(x,y) curve(1.0934^(0.7242^x), from=0, to=11, add=TRUE)dev.off()

*


Share
Improve this answer
Follow
edited Feb 17 "14 at 1:29
answered Feb 17 "14 at 0:59
*

Mark MillerMark Miller
11.5k2121 gold badges7070 silver badges123123 bronze badges
Add a comment |

Your Answer


Thanks for contributing an answer to Stack Overflow!

Please be sure to answer the question. Provide details and share your research!

But avoid

Asking for help, clarification, or responding to other answers.Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.

See more: Read Diary Of An Oxygen Thief Read Online Free, Diary Of An Oxygen Thief By Anonymous


Draft saved
Draft discarded

Sign up or log in


Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Submit

Post as a guest


Name
Email Required, but never shown


Post as a guest


Name
Email

Required, but never shown


Post Your Answer Discard

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy


Not the answer you're looking for? Browse other questions tagged r curve-fitting nls or ask your own question.


The Overflow Blog
Featured on Meta
Linked
-3
facing error with "nlsLM" in R?
1
Nonlinear total least squares/Deming regression
Related
0
another: "singular gradient matrix at initial parameter estimates"
1
wrapnls: Error: singular gradient matrix at initial parameter estimates
3
R and NLS: singular gradient matrix at initial parameter
1
nls singular gradient matrix at initial parameter estimates
0
R: nls() error. "singular gradient matrix at initial parameter estimates"
0
R nlsModel singular gradient matrix at initial parameter estimates error initial parameter estimation problem
1
R - Singular gradient matrix at initial parameter estimates
Hot Network Questions more hot questions

Question feed
Subscribe to RSS
Question feed To subscribe to this RSS feed, copy and paste this URL into your RSS reader.


*

lang-r
Stack Overflow
Products
Company
Stack Exchange Network
site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. rev2021.11.11.40730


Stack Overflow works best with JavaScript enabled
*

Your privacy

By clicking “Accept all cookies”, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.