- Written by: Thomas Weise
Today, we published the first version of a new R package at github.com/thomasWeise/dataTransformeR for normalizing and transforming numerical data.
When we fit models to data, we often do not want to use the raw data as-is. Instead, we usually want to fit models to normalized or log-scaled versions of the data. If all data elements are in [0,1], this makes it easier to pick initial parameter values for models. If there are exponential relationships present in data sets, we may want to get rid of them by log-scaling the data. This means that, after the models have been fitted, we need to transform the model back by applying the inverse of the data transformation to the model.
This package uses our functionComposeR package to construct and apply such bijective transformations. The core of this package are the Transformation and TransformedData S4 classes and the routines to construct instances of them.
Read more: dataTransformeR: An R Package for Normalizing and Transforming Numerical Data
- Written by: Thomas Weise
Today, we published the first version of a new R package at github.com/thomasWeise/functionComposeR for composing and canonicalizing functions. When we combine functions in R in the form of g(f(x)), we have the problem that the result is rarely human readable. This results from two problems. The first problem is that variables inside the function are evaluated in the environment of the function and even if they are constants, they will remain as variables. Thus, when printing a function f(x), I may sometimes something like a k*x inside, but may not know the value of k, even though it may be perfectly known in the function's environment and a constant. The second problem is that this also applies to nested functions, so there may be something like f=function(x) x+g(x) where g is a well-defined function, but printing f will not reveal the nature of g. Both of these issues also make evaluating the functions slower, as we could resolve the variables to constants and inline the nested functions' bodies, but instead evaluate them as variables and function calls, respectively. With our new package, we try to solve all of these issues at once. We provide a tool for combining functions and one for canonicalizing functions, i.e., for resolving all resolve-able components of a function.
Read more: functionComposeR: An R Package for Composing Functions
- Written by: Thomas Weise
Today is the last day of the year of the Rooster, tomorrow will be the year of the Dog.
The pary secretary of our university, Prof. Dr. Jingmin CAI [蔡敬民党委书记] therefore visited the quarters of foreign exchange students and foreign staff to wish everyone a Happy New Year. We wholeheartedly join Prof. Cai in his wishes and hope that all our university's members and their families will have a happy, healthy, and successful new year!
Happy New Year!
- Written by: Thomas Weise
Today, I attended a Spring Festival Get-Together [合肥市春节团拜会] held by the Hefei Municipal Government. After short welcome speeches by the representatives of the city government, an array of great singers, dancers, and comedians delivered absolute astonishing and impressing performances. I am very happy and thankful for being invited to such a nice event.
Read more: Prof. Weise attends the Hefei City Spring Festival Get-Together [春节团拜会]
- Written by: Thomas Weise
On Friday, February 2nd, I attended the Hefei City Chinese-Foreign Friendship Spring Festival Celebration [合肥市举办2018年华人华侨友好人士新春联谊会] held by the Hefei Municipal Government and the Hefei Overseas Chinese Affairs Office [侨务处]. The event was really nice, at a very beautiful venue, and well-attended with over 60 delegates. A welcome speech was given by the Hefei City Vice-Mayor Qingen Peng [彭庆恩], followed by discussion contributions by several international delegates.
I had the honor to also give a short speech, which I used to thank the Hefei Administration and Hefei University for the excellent support they provide for international experts. The nice environment that they have created allows us foreigners to feel at home in Hefei. During my eight years working full-time in Hefei, I have witnessed an incredible growth and development. I am therefore convinced that this city has a great future and I used this opportunity to express these feelings. Unfortunately, I had a very bad cold on that day and therefore had to leave early.