Generating the corresponding public key of a private key

[Angelos Ching]

Hi,

Can I always expect the following commands, when given the same
private key, to generate the same public key albeit in different format?
# ssh-keygen -y -f id_rsa
# ssh-keygen -e -f id_rsa

Because I'm dealing with one private key that is generating different
public key when the above commands were executed.
The output between the 2 commands are different, but they are
consistent for any number of runs.
Moreover, if I copy id_rsa to, say, id_rsa.priv:
# ssh-keygen -y -f id_rsa.priv
# ssh-keygen -e -f id_rsa.priv
would generate the same public key output.

Running OpenSSL 1.0.0-fips 29 Mar 2010

Best regards,
Angelos