std exception 'class std::out_of_range' : 'invalid unordered_map<K,T> key' was caught

Hello all,

I use simulink 2020b and when i run my model and it reach the initializing step I get the error " std exception 'class std::out_of_range' : 'invalid unordered_map<K,T> key' was caught ", it doesn't even show where the error is from or which block,

any Idea how to approach this error ?

[Amish]

Can you share the model or exact error message? Some screenshots might help understand the issue better.

[Hamza]

I can't share the model but this is the Error I get after compiling and the start of initializing

Answer 1

[Spruha]

Hi Hamza,

The error "class std::out_of_range": "invalid unordered_map<K,T>key" means that the model is trying to access a key in an unordered_map that does not exist. This issue often occurs in complex models that contain nested subsystems or several data dictionaries. Without the model, I can only suggest potential causes.

Possible causes can be:

• When there is complex interaction between nested subsystems, it may lead to timing issues where one subsystem is trying to access data before it's been generated by another.
• A block might be trying to access data in the unordered_map before the data is inserted, this data dependency can lead to an invalid key error.
• When there is custom S-Functions or Embedded MATLAB Functions with internal unordered_map implementation, there could be logic errors or incorrect interactions with other data structures

You can try these to fix the error:

• Verify your model's subsystem relationships, initialization, and data flow.
• To identify the problem, use displays, scopes, and limited simulation stepping.
• Check for logical problems in the custom blocks.

Hope this helps!