NEWS

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inflection 1.3.7 (2025-07-17)

1. Fix minor issue of Author in DECRIPTION file

inflection 1.3.6 (2022-06-15)

1. Fix minor issue of item values at help files for OS "-linux-x86_64-debian-clang", "r-devel-linux-x86_64-debian-gcc"

inflection 1.3.5 (2019-06-28)

New functions added for knee point estimation

• check_curve() checks a curve for its convexity type
• uik() finds the UIK estimation for elbow or knee point of a curve
• d2uik() performs UIK method on the approximation of second order derivatives

The Unit Invariant Knee (UIK) estimator is described in article:

• Demetris T. Christopoulos (2016). Introducing Unit Invariant Knee (UIK) As an Objective Choice for Elbow Point in Multivariate Data Analysis Techniques. Available at SSRN: http://dx.doi.org/10.2139/ssrn.3043076

Vignettes added for the package

Install the inflection package and then read vignettes:

• vignette('inflection', package ='inflection') an introductory vignette
• vignette('inflectionDevelopingMethods', package ='inflection') reproduction of results for article:
  • Demetris T. Christopoulos (2014). Developing methods for identifying the inflection point of a convex/concave curve. arXiv:1206.5478v2 [math.NA]. https://arxiv.org/pdf/1206.5478v2
• vignette('inflectionMissionImpossible', package ='inflection') a vignette for ‘impossible’ missions

Minor changes

Remove the option to plot in two separate pdfs ‘ese_iterations.pdf’, ‘ede_iterations.pdf’ from findipiterplot() and open new plot windows instead of saving files.

inflection 1.3 (2017-05-13)

Use of parallel computing under request (doparallel=TRUE) for the functions:

• ese()

• bese()

• findiplist()

• findipiterplot()

Repair of function findipiterplot()

1. Fix bugs in calling the function
2. Remove indirect methods CRESE, CREDE due to their limited functionality
3. Plot in two separate pdfs ‘ese_iterations.pdf’ and ‘ede_iterations.pdf’
4. Check for the existence of sufficient number of results before creating confidence intervals

inflection 1.2 (2016-06-10)

1. The function eixf(x, y, f, i) was removed as not essentially necessary
2. New functions with self declaring names were added:

• ese(x,y,index)
• bese(x,y,index)
• ede(x,y,index)
• edeci(x,y,index)
• bede(x,y,index) All functions require length(x)>=4 in order to create numeric output

1. The function findipiterplot(x,y,index) was improved and became findipiterplot(x, y, index, plots = TRUE, crossrun = FALSE, ci = FALSE)
2. Changes in NAMESPACE
3. Reference to new paper:

Demetris T. Christopoulos (2016). On the efficient identification of an inflection point.International Journal of Mathematics and Scientific Computing, (ISSN: 2231-5330), vol. 6(1). https://demovtu.veltech.edu.in/wp-content/uploads/2016/04/Paper-04-2016.pdf