Matlab coder cannot find knnSearch function

Hello,

I am trying to convert a Matlab function to C code. Part of this function uses the built-in pcregisterloam() function; it runs successfully in Matlab. However, when I try to compile it, I recieve an error related to the pcregisterloam() function stating:

"Undefined function or variable 'knnSearch'. " (see attached for a screenshot).

If I open the function knnSearch, I'm directed to the file knnsearch.m (note the lowercase "s"), so I assume the link to the proper function is broken somehow.

At the matlab terminal, running

help knnSearch

gives:

--- knnSearch not found. Showing help for knnsearch instead. --

However, running

which knnSearch

yields:

knnSearch is a built-in method % vision.internal.Kdtree method

How can I direct the coder to the proper function? Thanks in advance!

Answer 1

[Udit06]

Hi Michael,

I was facing a similar issue in MATLAB R2023a. However, I was able to generate the C code in MATLAB R2024a. So, you can consider updating to a latest version of MATLAB to resolve the issue.

Running "which" command with an inbuild function appears to be case insensitive. I tried running the following command to verify that the results corresponds to case insensitive search:

which PLOT

/MATLAB/toolbox/matlab/bigdata/@tall/plot.m  % tall method

So, in your case, there is no method with the name "knnSearch". The correct method name is "knnsearch".

I hope this helps.