QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: esp on January 16, 2012, 21:22

Title: Angstrom vs Ang
Post by: esp on January 16, 2012, 21:22

Maybe I am just not familiar with the unit "Ang", but when I try to modify values that are in Angstroms the program keeps giving me errors that I am not using Ang units ... How do we know when to use "Ang" and when to use "Angstrom"?   I tested 1*Ang == 1*Angstrom and it returned true, so ... are they the same or not?

Title: Re: Angstrom vs Ang
Post by: Nordland on January 16, 2012, 22:40

They are so much the same that they share address.  ;D

Try running:

Code: python

print id(Ang)
print id(Angstrom)

This will show that both point to the same point in memory. So there is no difference in any respect if you use Angstrom or Ang.
It is just a convenience if you want to be more or less explicit with your units. There is a long list of dual names. Like Rydberg/Ry and Ha/Hartree.