ourMELONS/PITFALLS.md

Known pitfalls

The following behavioral differences have been detected between the Matlab functions and their R counterparts. In order to save time, these differences will not be addressed, since they could require extensive reworking of a function. However, such differences may very well cause unexpected problems in some situations, which is why compiling this list is so important. The tables below might provide a good starting point for identifying and fixing bugs.

As general remarks, one should keep in mind that:

• For compliance with IEC 60559, the round in base R rounds .5 to the nearest even integer, whereas the homonym function in Matlab rounds up (or down, if negative).
• Some clobal variables have been added as a new (last) argument to the function they appear in.
• When a function is defined on Matlab with multiple outputs, as in [y1, y2] = f(x), it will output only y1 if called without assignment, as in f(3), or if called with a one-length assignment, as in a = f(3). In order to receive the full output, one must assign two variables to the left side of the assignment operator, as in [a, b] = f(3). rBAPS Functions that might be affected by this behavior include etsiParas.

Some functional differences in rBAPS functions

Function	Argument	Value	Matlab output	R output
ownNum2Str	number	NaN	'NAN'	error
ownNum2Str	number	<vector>	'<vector elements>'	'<vector elements>' + warning
repmat	length(n)	> 2	> 2D matrix	2D matrix

Some functional differences in base Matlab functions

Function	Matlab output	R output
max	Can handle complex numbers	Cannot handle complex numbers

Wanna help debugging?

If you find an error, one of the first things to try is to compare the R code with its MATLAB equivalent, which you can find here. Some common causes are:

1. Using () to subset an object in R. R uses [] for that, whereas Matlab uses () for both function calling and object subsetting. Therefore, often objects will be mistakenly interpreted as functions by R due to improper translation.