entropy: Standard measures of complexity for strings

In acss: Algorithmic Complexity for Short Strings

Description

Functions to compute different measures of complexity for strings: Entropy, Second-Order Entropy, and Change Complexity

Usage

entropy(string)

entropy2(string)

change_complexity(string)

Arguments

string

character vector containing the to be analyzed strings (can contain multiple strings for the entropy measures).

Details

For users who need advanced functions, a comprehensive package computing various versions of entropy estimators is available entropy. For users who just need first and second-order entropy and which to apply them to short string, the acss package provides two functions: entropy (first-order entropy) and entropy2 second-order entropy.

Change complexity (change_complexity) assesses cognitive complexity or the subjective perception of complexity of a binary string. It has been comprehensively defined by Aksentijevic and Gibson (2012). Although the algorithm will work with any number of symbols up to 10, the rationale of Change Complexity only applies to binary strings.

Value

numeric, the complexity of the string. For entropy and entropy2 of the same length as string. change_complexity currently only works with inputs of length 1.

References

Aksentijevic & Gibson (2012). Complexity equals change. Cognitive Systems Research, 15-17, 1-16.

Examples

strings1 <- c("010011010001", "0010203928837", "0000000000")
strings2 <- c("001011", "01213", "010101010101")

entropy(strings1)
entropy("XYXXYYXYXXXY") # "same" string as strings1[1]
entropy(c("HUHHEGGTE", "EGGHHU"))

entropy2(strings1)
entropy2("XYXXYYXYXXXY")

entropy2(strings2)

change_complexity(strings1)
change_complexity("XYXXYYXYXXXY")

Example output

Loading required package: acss.data
 010011010001 0010203928837    0000000000 
    0.9798688     2.6235166     0.0000000 
XYXXYYXYXXXY 
   0.9798688 
HUHHEGGTE    EGGHHU 
 2.197160  1.918296 
 010011010001 0010203928837    0000000000 
     1.867634      3.584963      0.000000 
XYXXYYXYXXXY 
    1.867634 
      001011        01213 010101010101 
   1.9219281    2.0000000    0.9940302 
 010011010001 0010203928837    0000000000 
     6.447439      6.443398      0.000000 
XYXXYYXYXXXY 
    6.447439 

acss documentation built on May 1, 2019, 7:56 p.m.