I want to do some research about dark matter halos evolution between Illustris-1 and TNG-100. However dark matter particle IDs are different in two simulations, so I can't match DM particles between two simulations. I want to know if there was some way to transform TNG-100's particleIDs to Illustirs-1's particleIDs(or on the contrary), so I can match halos by matching their particles' ID. Thanks to all the answers.
Yes there is a mapping between the two, there is some code for this I can try to find.
Actually easiest, I think, would be to use the ICs of both simulations. They should be in the same order (I think), so the lists of PartType1/ParticleIDs in both files gives the mapping.
For instance, the first ID in the Illustris-1 IC is 1317624619938222478 and in TNG100-1 it is 101. At z=0 I found these two DM particles at [ 7895.32591742, 71965.96257959, 952.11971636] and [ 8049.388247 , 71862.37857107, 931.39879926], respectively, so pretty close. You should verify a bit more that the mapping implied by assuming the two ICs are in the same particle-order makes sense.
[ 7895.32591742, 71965.96257959, 952.11971636]
[ 8049.388247 , 71862.37857107, 931.39879926]