Erratum

Open Access

Erratum

Open Access

- Marshall Abrams
^{1}Email author

Complex Adaptive Systems Modeling2014**2**:1

**DOI: **10.1186/2194-3206-2-1

© Abrams; licensee Springer. 2014

**Received: **3 December 2013

**Accepted: **3 December 2013

**Published: **6 January 2014

After publication of (Abrams 2013), I discovered errors in two formulas in the **settle-nets** paragraphs of the **POPCO main loop** section in **Methods** (page 13 in the PDF file). I correct these errors here. In the definition of the weighted sum *n*_{
i
} of input activations *a*_{
j
} from nodes *j* to node *i* across links with weights *w*_{
ij
}, the direction of the inequality was reversed. The definition of *n*_{
i
} should read:

${n}_{i}=\sum _{j}{w}_{\mathit{\text{ij}}}max(0,{a}_{j})\phantom{\rule{2.77626pt}{0ex}}\phantom{\rule{2.77626pt}{0ex}}\phantom{\rule{2.77626pt}{0ex}}\text{for}\phantom{\rule{2.77626pt}{0ex}}{w}_{\mathit{\text{ij}}}<0\phantom{\rule{0.3em}{0ex}}.$

There were also errors in the definition of *s*_{
i
}, the weighted sum of a node’s current activation *a*_{
i
} and its summed inputs *p*_{
i
} and *n*_{
i
} across positively and negatively weighted links, respectively. The definition of *s*_{
i
} should read as follows:

${s}_{i}=(1-.1)\phantom{\rule{0.3em}{0ex}}{a}_{i}+(.99-{a}_{i})\phantom{\rule{0.3em}{0ex}}{p}_{i}+({a}_{i}-(-.99\left)\right)\phantom{\rule{0.3em}{0ex}}{n}_{i}$

I regret these errors and hope that they do not cause confusion. Full source code for the version of POPCO used in Abrams (2013) can be found at https://github.com/mars0i/popco.

(1)

Department of Philosophy, University of Alabama at Birmingham

- Abrams M: A moderate role for cognitive models in agent-based modeling of cultural change.
*Complex Adaptive Syst Model*2013, 1(16):1–33.MathSciNetGoogle Scholar

© Abrams; licensee Springer. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.