Remove unnecessary functions in ImuFactorsExample.cpp

[Taeyoung96]

@varunagrawal
This is a simple PR to improve code readability.

In ImuFactorsExample.cpp, when optimizing using isam2, the isam2->update(); function does not affect the results.
I think it's better to remove this function to avoid confusion.

If this PR helps, I'd appreciate it if you merge. 😄
Thanks,

[varunagrawal]

@Taeyoung96 thanks for the PR! We always appreciate help from wonderful community members like yourself. 🙂

So just a quick clarifying question: the second isam->update method runs another optimization step, so you can think of it as running gradient descent for 2 timesteps instead of 1. Does removing the 2nd update call significantly affect the final results?

I would love to see some plots of the before and after and ensure they both look the same (along with the numerical values) since we don't have unit tests for this thing. If they are indeed the same, I will gladly approve and merge this PR.

[Taeyoung96]

@varunagrawal Thanks for your quick reply!

After checking the results, the update() function did not affect the overall results.
The result of the .csv file has the same numerical values. 😃
(I performed it about 5 times, and I was able to get the same result.)

Here are my result .csv files below.
imuFactorExampleResults(withUpdate).csv
imuFactorExampleResults(withoutUpdate).csv

And the result of the plotting is as follows.

[varunagrawal]

Amazing! Thanks @Taeyoung96

[varunagrawal]

LGTM