# 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](matlab). 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.