12.3.1.4.4. grw

Time of flight and mobility from the graph random walk: mean hitting times of the sink region from a sparse linear solve (no sampling), Chen, van der Hoorn, Baumeier, arXiv:2405.15836 The following table contains the defaults input options for the calculator, The default OPTIONAL means this option is switched off, if no input is given. REQUIRED arguments have to be specified, otherwise an error is thrown.

Property Name	Default Value	Description	Valid Input
carriertype	electron	Carrier type	electron hole singlet triplet
temperature	300	Temperature	float+
field	0.0 0.0 0.0	External electric field; for detailed balance (symmetric solver) it must be along the transport normal
tof.axis	a	Box vector across which the periodicity is cut; transport runs along the normal of the face spanned by the other two box vectors, from fractional coordinate 0 (source side) to 1 (sink side)	a b c
tof.source.thickness	1.0	Thickness of the source slab at the face with fractional coordinate 0, measured along the normal (0: no slab criterion)	float+
tof.source.pattern		Segment type wildcard, e.g. ‘Alq3*’ (empty: no pattern criterion)
tof.sink.thickness	1.0	Thickness of the sink slab at the face with fractional coordinate 1, measured along the normal (0: no slab criterion)	float+
tof.sink.pattern		Segment type wildcard (empty: no pattern criterion)
tof.ignoretypes		Segment types (wildcards, separated by commas or spaces) that take no part in transport: no hops to or from them
numberofcarriers	1	Number of carriers with site exclusion; the state space has n^N/N! states, so 1 or 2	1 2
observable	first	Two carriers: first = time until the first carrier reaches the sink (as in arXiv:2405.15836); transit = mean transit time per carrier, carriers removed at the sink (ToF transient). Identical for one carrier	first transit
maxstates	50000000	Two carriers: largest number of pair states (memory guard)	int+
solver	auto	Linear solver. auto: with detailed balance Cholesky (up to directlimit unknowns) or conjugate gradients on the symmetrized generator, otherwise LU or BiCGSTAB	auto cholesky lu cg bicgstab
directlimit	5000	auto: largest number of unknowns for the direct solvers	int+
tolerance	1e-14	Relative residual of the iterative solvers; must be tight because trap modes dominate the hitting times	float+
maxiterations	100000	Iteration limit of the iterative solvers	int+
sourcefile	grw_sources.dat	Output: mean hitting time and its standard deviation per source segment (empty: none)
resultfile	grw_results.dat	Output: main results as ‘key value unit’ lines (empty: none)
occupationfile	grw_occupation.dat	Output: expected time spent on each segment (where the time of flight is spent; empty: none)

Note

An xml file containing the defaults for the grw calculator can be created via -p grw -o FILENAME command line options `