Error with derived trajectories

[thepoole]

When using trajectories modified by strip or append, I get errors for later analysis (e.g. dssp, sander, pca) due to some type mismatch. This can be worked around either by using a deep-copy or saving and loading the trajectory to file.

Here is a snippet of code you can use for and example, in this case I have a dictionary of trajectories but this setup should work with any trajectory constructed with append, strip, or selections (i.e., traj["@ca"]):

`

Create an empty trajectory

combine = pytraj.Trajectory()

Parse the dictionary of trajectories

for item in traj_dict:
if(combine.n_atoms < 1):
combine = traj_dict[item].copy()
else:
combine.append(traj_dict[iem])

This is a work-around to some bug, I should forward it to pytraj team with love

combine = combine.copy()

Getting the delicious data

data = pytraj.pca(combine, mask="@ca", n_vecs=2)
`

[hainm]

Thank you @thepoole for your report.