Home
Reference Guides
Reference guides are available for functions and commands supported by OML, Tcl, and Python.
Reference Guide for OpenMatrix Language Functions
The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
Special Functions Commands
besseli
Modified Bessel function of the first kind.

Welcome
What's New
Discover new features and enhancements.
Get Started
Discover Compose, including its language support and system requirements.
Tutorials
The Compose tutorials and associated example model files help introduce you to the basic functionality of the software.
User Guide
Learn about the features and functionality available in Compose.
Reference Guides
Reference guides are available for functions and commands supported by OML, Tcl, and Python.
- Scripting Guide for OpenMatrix Language
  OpenMatrix is a mathematical scripting language.
- Reference Guide for OpenMatrix Language Functions
  The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
  - ABF Commands
  - Altair Integration Commands
  - Audio Commands
  - CAE Commands
  - CAE Reader Commands
  - CAE Reader 3D Commands
  - CAE Writer Commands
  - Calculus Commands
  - Computer Vision Commands
  - Communication Commands
  - Control System Commands
  - Core Minimal Interpreter Commands
  - Data Structure Commands
  - Differential Equations Commands
  - Elementary Math Commands
  - File I/O Commands
  - Geometry Commands
  - GUI Commands
  - HDF5 Reader Commands
  - HDF5 Writer Commands
  - hstpyfit Commands
  - Image Commands
  - JSON Commands
  - Library Manager Commands
  - Linear Algebra Commands
  - Logical Commands
  - Machine Learning Commands
  - Optimization Commands
  - Plotting Commands
  - PSIM Commands
  - Polynomial Math Commands
  - Signal Processing Commands
  - Special Functions Commands
    - besselh
      Bessel functions of the first or second kind.
    - besseli
      Modified Bessel function of the first kind.
    - besselj
      Bessel function of the first kind.
    - besselk
      Modified Bessel function of the second kind.
    - bessely
      Bessel function of the second kind.
  - Statistical Analysis Commands
  - String Operations Commands
  - System Commands
  - Table Commands
  - Tcl Bridge OML Commands
  - Tcl Bridge Tcl Commands
  - Time Commands
  - Trigonometry Commands
  - OML to Python Bridge Commands
  - Python to OML Bridge Commands
- Python in Compose Reference Guide
Appendix
Get help for the optional libraries that are available in the Extension Manager.
Frequently Asked Questions
You've got questions? We've got answers!

besseli

Modified Bessel function of the first kind.

Syntax

[i,ierr] = besseli(alpha, x, opt)

Inputs

alpha: The function order.; Type: double; Dimension: scalar | vector | matrix
x: The function argument.; Type: double | complex; Dimension: scalar | vector | matrix
opt: The scaling option.; If set to 1 or true the result contains a factor of exp(-abs(imag(x))).; Dimension: scalar | vector | matrix

Outputs

i

The Bessel function values.

Dimension: scalar | vector | matrix

ierr

The return status flag.

Dimension: scalar | vector | matrix

info = 0: Successful return.
info = 1: Input error, returned NaN.
info = 2: Overflow condition, returned Inf.
info = 3: Calculation has lost at least half of machine accuracy.
info = 4: Calculation has lost significance, returned NaN.
info = 5: Algorithm failed to converge, returned NaN.

Examples

Unscaled example:

i = besseli(3,[10:12;13:15])

i = [Matrix] 2 x 3
 1758.38072   4757.92757   12832.89304
34537.96038  92820.61916  249218.41965

Scaled example:

i = besseli(3,[10:12;13:15],1)

i = [Matrix] 2 x 3
0.07983  0.07947  0.07885
0.07807  0.07718  0.07624

Comments

If alpha and x have different dimensions, a singleton dimension in either variable is expanded to match the corresponding dimension length of the other variable.