Description Usage Arguments Details Value Examples
Transcript apply diversity/richness indices.
1 |
text.var |
The text variable. |
grouping.var |
The grouping variables. Default NULL generates one output for all text. Also takes a single grouping variable or a list of 1 or more grouping variables. |
These are the formulas used to calculate the indices:
Shannon index:
H_1(X)=-∑\limits_{i=1}^R{p_i};log;p_i
Shannon, C. E. (1948). A mathematical theory of
communication. Bell System
Simpson index:
D=\frac{∑_{i=1}^R{p_i};n_i(n_i -1)}{N(N-1))}
Simpson, E. H. (1949). Measurement of diversity. Nature
163, p. 688
Collision entropy:
H_2(X)=-log∑_{i=1}^n{p_i}^2
Renyi, A. (1961). On measures of information and entropy.
Proceedings of the 4th Berkeley Symposium on Mathematics,
Statistics and Probability, 1960. pp. 547-5661.
Berger Parker index:
D_{BP}=\frac{N_{max}}{N}
Berger, W. H., & Parker, F. L.(1970). Diversity of
planktonic Foramenifera in deep sea sediments. Science
168, pp. 1345-1347.
Brillouin index:
H_B=\frac{ln(N!)-∑{ln(n_1)!}}{N}
Magurran, A. E. (2004). Measuring biological diversity. Blackwell.
Returns a dataframe of various diversity related indices for Shannon, collision, Berger Parker and Brillouin.
1 2 3 4 |
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.