MultiComponent

• MC FAQ

• MC Release Notes

• MC instructions (will be obsolete once online help is finished)

• MC Online Help  (under construction)

• MC Benchmarks

• Parallelization and Caching (<--- have a look at the new algorithms!)

A detailed article about MultiComponent is available:

Analyzing CW EPR Spectra of Nitroxide Labeled Macromolecules 

by Christian Altenbach and David Budil.

As part of the Springer Nature Content Sharing Initiative, a shareable full-text access to a view-only version of the paper is also available via a  SharedIt link, where readers  are able to use Enhanced PDF features such as annotation tools, one-click supplements, citation file exports and article metrics.

This article is open access thanks to the UCLA library and is part of a special collection of Applied Magnetic Resonance.

 Special Issue: Wayne Hubbell - on the Occasion of His 80th Birthday 

This special issue is devoted to Professor Wayne Hubbell on the occasion of his 80th birthday. It aims to recognize the many contributions of Wayne Hubbell to Electron Spin/Paramagnetic Resonance (ESR/EPR) spectroscopy. Topics covered include but are not limited to: Advanced experimental/theoretical techniques in ESR/EPR spectroscopy; Applications of ESR/EPR spectroscopy in biophysics and protein science; Spin chemistry and spin labeling techniques; high-pressure ESR/EPR technique and applications in biophysics; Structure and dynamics of transmembrane protein studies. 

A LabVIEW program for fitting of multicomponent CW EPR spectra.

MultiComponent is a general purpose simulation and fitting platform for Nitroxide CW EPR spectral lineshapes. All UI and fitting procedures are written in LabVIEW and allow great flexibility in fitting parameter and fitting algorithm selection.

The core model to calculate an EPR spectrum as a function of input parameters is implemented as DLL based on the Budil/Freed MOMD program, adapted by Thomas Risse and compiled in Intel FORTRAN. (All limitations of the fortran code are retained). The LabVIEW code is designed to calculate spectra in parallel on multicore hardware (up to 256 cores are supported). It also uses extensive caching to avoid unnecessary DLL calls.

Important Note:

Versions 742 and higher offer a major performance gain and everybody running older versions is strongly encouraged to upgrade.

New features are:

• Full multicore utilization, even for single component spectra. Up to 256 CPU cores supported (details).

• Vastly improved fitting algorithms (e.g. Adjustable lambda settings for Levenberg Marquardt, a parallel Monte Carlo version).

• 3D visualization of ordering potentials.

• Many other enhancements! 

Some Features:

• • Up to four spectral components. Each component is the full Freed/Budil model, including MOMD.

  • Flexible parameter assignment. Any parameter can be held fixed or be fittable.

  • Parameters (fixed or fittable) can be shared by multiple components if desired.

  • Frequency input.

  • Choice of fitting algorithm (Levenberg-Marquardt, Nelder-Mead Downhill Simplex, Monte Carlo, etc.).

  • All fitting algorithms are tunable. Default tuning parameters are optimized out of the box.

  • Spectral weighting to emphasize or disregard spectral regions.

  • Real-time display of fitting progress (graph, chisquare, fitting parameter values)

  • Fitting can be interrupted at any time.

  • Full multiprocessor support for faster computations.

  • Reads ASCII, ELEXSYS, EMX data files.

  • Writes multicolum ASCII (field, data, spectrum, weight, spectral components)

• • Phase is a fittable parameter. (Important for spectra recorded with a loop-gap resonator).

  • Several options for weighting spectral areas differently.

• • Significant performance gains due to parallelization and caching, algorithm tuning and many other algorithm improvements.

  • 3D visualization of ordering potentials

• Calculation of order parameters from potentials

• Support for arbitrary spectrum size (within reason!).

• See release notes for details.