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) Cell In[3], line 1 ----> 1 shifts = md.nmr.chemical_shifts_spartaplus(trj)  2 shifts[0:10] File ~/checkouts/readthedocs.org/user_builds/mdtraj/envs/latest/lib/python3.13/site-packages/mdtraj/nmr/shift_wrappers.py:303, in chemical_shifts_spartaplus(trj, rename_HN)  301 binary = find_executable(SPARTA_PLUS)  302 if binary is None: --> 303 raise OSError(  304 f"External command not found. Looked for {SPARTA_PLUS} in PATH. "  305 "`chemical_shifts_spartaplus` requires the external program SPARTA+, available at "  306 "http://spin.niddk.nih.gov/bax/software/SPARTA+/",  307 )  309 names = [  310 "resSeq",  311 "resName",  (...) 318 "SIGMA",  319 ]  321 with enter_temp_directory(): 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)