MATLAB: Mystery Error; same code runs fine the 2nd time, but not the 1st!

array allocationMATLAB

The 1st run produces this error: "Unable to perform assignment because the left and right sides have a different number of elements." The same exact identical code, works fine the 2nd time around. What gives? Installation issues? Cache problems?
MATLAB Version: (R2019a) Update 1

Best Answer

  • Without seeing the relevant part of the code, answering is based on guessing.
    I guess, that your code is a script and not a function. Inside the script some variables are defined at the first run such that the second run can use them.
    Neither "installation issues" nor "cache problems" are standing to reason. Most likely this is a simple programming error. You can use the debugger to test this. Another approach is to convert the script into a function, and check, if the problem occurs every time. Then you know that the data shared with previous runs is the source of the different behaviour.