Default setting for 'mutationRangeStep '

[lukknapen]

• Does the default setting

   <module name="timeAllocationMutator" >
      <!-- Mutation Range Step, default = 1 second -->
      <param name="mutationRangeStep" value="1.0" />
   </module>

make sense ? In org/matsim/core/population/algorithms/PlanMutateTimeAllocation.java
and org/matsim/core/population/algorithms/PlanMutateTimeAllocationSimplified.java the second term in

double t = time.seconds() + (int)((this.random.nextDouble() * 2.0 - 1.0) * this.mutationRange);

always equals zero for the default setting due to the 'double to int' type casting.
Hence, the default value does not induce timeMutation.

This is because (int)(someDoubleValue) uses the 'rounding to zero method';
see https://docs.oracle.com/javase/specs/jls/se17/html/jls-5.html#jls-5.1.3

• Was this default value chosen on purpose ? If so, it is useful to extend the comment for this setting in the logFile.log It now just says <!-- Mutation Range Step, default = 1 second --> which is correct but may be insufficient.

[jfbischoff]

Hi Luk,
I have worked a bit on the TimeAllocationMutator during the last code sprint, there is only one TimeMutator now left:
https://github.com/matsim-org/matsim-libs/blob/fb982e55294034d1afe44084b7b0322bcd9d17a0/matsim/src/main/java/org/matsim/core/population/algorithms/MutateActivityTimeAllocation.java

There is now a mutationRangeStep and a mutationRange. The step is indeed set by default to 1 second, whereas the mutationRange is 1800 seconds.
The step can be set to e.g., 60 seconds or 5 minutes to achieve more relevant time mutations.

[lukknapen]

hello Joshka, - i am using 5 minutes in my simulations (after discovering the strange default value) thanks for your help luk

…

On Mon, Jan 13, 2025 at 4:01 PM Joschka Bischoff ***@***.***> wrote: Hi Luk, I have worked a bit on the TimeAllocationMutator during the last code sprint, there is only one TimeMutator now left: https://github.com/matsim-org/matsim-libs/blob/fb982e55294034d1afe44084b7b0322bcd9d17a0/matsim/src/main/java/org/matsim/core/population/algorithms/MutateActivityTimeAllocation.java There is now a mutationRangeStep and a mutationRange. The step is indeed set by default to 1 second, whereas the mutationRange is 1800 seconds. The step can be set to e.g., 60 seconds or 5 minutes to achieve more relevant time mutations. — Reply to this email directly, view it on GitHub <#3647 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHKFB4E45Q3EKQ737PFD4D2KPIN5AVCNFSM6AAAAABUIR5WY2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKOBXGM2DGMBSGU> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[lukknapen]

• my comment was that the default value (which disables timeMutation) should be documented at least in the notes that come in the logFile
• the default value 'an sich' is not a problem but the MATSim guide advises to start from the default settings and as far as i can see there is no warning that this disables time mutation. I only discovered it by code reading.