LMFIT(7)

📦
version 10.0 · 2 versions
, in fedora 44

🎀 LMFIT 🎀

okay bestie, welcome to lmfit, section 7 of the manual (yes, the big-girl section, the library one, not the syscall one). it's giving C library, it's giving curve fitting, it's giving decades of FORTRAN trauma that somehow turned out iconic. let's get into it 💅

✨ NAME ✨

lmfit — Levenberg-Marquardt least-squares minimization

like literally that's the whole thing. that's what she does. 🦋

🌸 DESCRIPTION 🌸

so lmfit is a C library for Levenberg-Marquardt least-squares minimization and curve fitting. and the way that she's mature code?? no cap, she's built on decades-old algorithms straight out of the FORTRAN library MINPACK. vintage. timeless. ate. 👑

here's the vibe check on which function you actually want, because there are several and you will pick the wrong one if you don't read this:

  • wanna fit a data set {(x_i,y_i)|i=0,1,..} with a parametric curve f(x,t)? bestie, that's lmcurve(3) 🫶
  • wanna fit a data set {(x_i,y_i+-dy_i)|i=0,1,..} with a parametric curve f(x,t)? note the error bars, she's fancy — that's lmcurve2(3) ✨
  • need generic minimization of the Eucledian norm of a parametric vector? that's lmmin2(3) for you 💜
  • want the simpler legacy API with no error estimates? okay grandma, that's lmmin(3) 🌸

🧚 the example files, listen closely 🧚

for an example of how to use lmmin, go look at the source files lmcurve.h and lmcurve.c.

⚠️ DO NOT PATCH THESE FILES. i am so serious. do not. instead, copy and modify them to create your own, differently named version of lmcurve_data_struct, lmcurve_evaluate, and lmcurve. that's the whole assignment. that's the homework. 🎀

and for an example of how to use lmmin2 with weighted data, go look at the source files lmcurve2.h and lmcurve2.c.

⚠️ again for the people in the back: DO NOT PATCH THESE FILES EITHER. copy and modify them to make your own differently named version of lmcurve2_data_struct, lmcurve2_evaluate, and lmcurve2. periodt. 💅

💖 COPYING 💖

okay legal moment, but make it cute. copyright belongs to:

  • 1980-1999 University of Chicago
  • 2004-2015 Joachim Wuttke, Forschungszentrum Juelich GmbH

the Software is under the FreeBSD License 🌈 and the Documentation is under Creative Commons Attribution Share Alike 🦋

🌈 SEE ALSO 🌈

and the Homepage: https://jugit.fz-juelich.de/mlz/lmfit — go follow her, she posts. 💫

🐛 BUGS 🐛

found a bug? got a suggestion? do NOT suffer in silence bestie 😭 please send bug reports and suggestions to the author:

<j.wuttke@fz-juelich.de>

he wants to hear from you, fr fr. 📬

and that's the page!! this lil rewrite was served up by perl v5.42.0, dated 2026-01-16, which is when the LMFIT(7) magic got stamped into the universe. mwah, go fit some curves, you absolute main character 💅✨🎀

📦 where this page comes from