Dear all，

Something confused me about the “velocity” command. I used the command “velocity all create 300.0 492845 rot yes dist gaussian” to distribute velocity to all the molecular. According to my understanding , the velocity should be distributed randomly obeying gaussian distribution. Namely if i do the same simulation twice, the result should be different because the velocity of molecular should be different. But according to my result, i find that if the calculation is made in the same computer using the same cores, the result is the same. So that confused me a lot, how can the “velocity” command distribute the velocity? and can it remain unchanged in the same input?

Yours sincerely

David bootman.

Dear all，

Something confused me about the “velocity” command. I used the

command "velocity all create 300.0 492845 rot yes dist gaussian" to

distribute velocity to all the molecular. According to my understanding ,

the velocity should be distributed randomly obeying gaussian distribution.

Namely if i do the same simulation twice, the result should be different

because the velocity of molecular should be different.

this is where you go wrong. if you use the *exact* same input and the same

number of CPU cores, the result should be the same. to get a different set

of (pseudo!) random numbers, you have to use a different seed value.

axel.

But according to my result, i find that if the calculation is made in the

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