Calculating NMR observables with mdtraj.nmr()

An error occurred while executing the following cell: ------------------ shifts = md.nmr.chemical_shifts_spartaplus(trj) shifts[0:10] ------------------ --------------------------------------------------------------------------- OSError Traceback (most recent call last)  in  ----> 1 shifts = md.nmr.chemical_shifts_spartaplus(trj)  2 shifts[0:10] /d/nyc/mcgibbon-0/garden/CentOS7/prefixes/mdtraj/1.9.4-01c7/lib/python3.7/site-packages/mdtraj/nmr/shift_wrappers.py in chemical_shifts_spartaplus(trj, rename_HN)  274 binary = find_executable(SPARTA_PLUS)  275 if binary is None: --> 276 raise OSError('External command not found. Looked for %s in PATH. `chemical_shifts_spartaplus` requires the external program SPARTA+, available at http://spin.niddk.nih.gov/bax/software/SPARTA+/' % ', '.join(SPARTA_PLUS))  277   278 names = ["resSeq", "resName", "name", "SS_SHIFT", "SHIFT", "RC_SHIFT", "HM_SHIFT", "EF_SHIFT", "SIGMA"] OSError: External command not found. Looked for sparta+, SPARTA+, SPARTA+.linux in PATH. `chemical_shifts_spartaplus` requires the external program SPARTA+, available at http://spin.niddk.nih.gov/bax/software/SPARTA+/ OSError: External command not found. Looked for sparta+, SPARTA+, SPARTA+.linux in PATH. `chemical_shifts_spartaplus` requires the external program SPARTA+, available at http://spin.niddk.nih.gov/bax/software/SPARTA+/

(nmr.ipynb; nmr_eval.ipynb; nmr.py)