Crank is designed to create a dihedral grid, and fill in optimized geometries and energies into the grid, by running wavefront propagations of constrained optimizations.

• Numpy

• geomeTRIC molecule.py, also to enable the geometric-optimize command

• cctools.work_queue [Optional] (to enable the distributed computing feature)

python setup.py install

crank-launch <InputFile> <Dihedrals.txt> --init_coords <init_coords.xyz> -g <grid_spacing> -e <Engine> (--native_opt) (--wq_port XXX) (-v) > scan.log

crank-api current_state.pickle

<InputFile>: An Psi4, QChem or Terachem input file, servering as a template for constrained optimizations.

<Dihedrals.txt>: A txt file containing the definition of dihedral angles, each as 4 atom indices in one line. The number of dihedrals determines the dimension of the scanned grid.

--init_coords <init_coords.xyz>: File contains a trajectory of initial coordinates. Will be mapped to the closest grid point at beginning, replacing the geometry in <InputFile>.

-g <grid_spacing>: Integer number, divisor of 360, angle in degree between each grid point.

-e <Engine>: One of psi4, qchem, terachem

--native_opt: Flag, use quantum software's internal optimizer instead of geomeTRIC optimizer.

--wq_port XXX: Flag, use cctools.work_queue tool to distribute the calculations.

-v: Flag, turn on verbose printing, including the colorful status map :)

The DihedralScanner Class works together with the QMEngine Class, both can be imported and incorporated into other python scripts, to enable more features, and automated scanning for multiple molecules.