R TUTORIAL, Part I: Derivatives

R is a statistical analyzation language, and that means it is very good at data manipulation and data analyzation. One key way to analyze data is through plotting, and R excels in this field.

\[ y' = f(x,y), \qquad y(x_0 ) = y_0 . \]

Logical operators

As well as numerical vectors, R allows manipulation of logical quantities. The elements of a logical vector can have the values TRUE, FALSE, and NA (for “not available”). The first two are often abbreviated as T and F, respectively. Note however that code>T and F are just variables that are set to TRUE and FALSE by default, but are not reserved words and hence can be overwritten by the user. Hence, you should always use TRUE and FALSE. Logical vectors are generated by conditions. For example,

sets temp as a vector of the same length as x with values FALSE corresponding to elements of x where the condition is not met and TRUE where it is. 
     [,1] [,2] [,3]
[1,]    1    2    3
[2,]    4    5    6
[3,]    7    8    9

 

  1. Schiesser, W.E., An Introductory Comparison of Matlab and R, Lehigh University, Bethlehem, USA.
  2. Soetaert, K, Cash, J., Mazzia, F., Solving Differential Equations in R, 2012, Springer, Heidelberg New York Dordrecht London