# ICL

Improved Chung and Lee's method

References:

1. [10.1002/nme.6574](https://doi.org/10.1002/nme.6574)
2. [10.1002/nme.6054](https://doi.org/10.1002/nme.6054)
3. [10.1002/nme.1620372303](https://doi.org/10.1002/nme.1620372303)

## Syntax

```
integrator ICL (1) [2]
# (1) int, unique integrator tag
# [2] double, spectral radius, \rho_b, default: 0.5
```

## Remarks

The following constraint applies.

$$
0.5\leq\rho_b\leq1.0.
$$

If the model is linear elastic, it is possible to indicate using

```
set linear_system true
```

to speed up the computation.

## Accuracy Analysis

![icl-0.5](https://4006314410-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ5rMqEBbzA9NgGETGX%2Fuploads%2Fgit-blob-3055a99bca0eef5f84f1803255e77e127d17db34%2Ficl-0.5.svg?alt=media) ![icl-1.0](https://4006314410-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MQ5rMqEBbzA9NgGETGX%2Fuploads%2Fgit-blob-9d7974ce711cab6785a50c4c1a798a0eb2ff39f3%2Ficl-1.0.svg?alt=media)
