The TIS section¶
The TIS
section defines settings for (PP)TIS and (PP)RETIS simulations.
TIS settings
------------
aimless = True
allowmaxlength = False
freq = 0.5
high_accept = True
interface_sour = None
maxlength = 20000
n_jumps = 8
rgen = rgen
rescale_energy = False
seed = 1
shooting_moves = ['sh']
sigma_v = -1
zero_momentum = False
Keywords for the TIS section¶
The following keywords can be set for the TIS section:
Keyword | Description |
---|---|
aimless | Specify if the shooting is aimless or not. |
allowmaxlength | Specify if the maximum length should be determined randomly. |
freq | Define how often time reversal moves are performed. |
interface_sour | Sets the position of SOUR for Web Throwing. |
high_accept | Set the Stone Skipping version to use. |
maxlength | Set the maximum length of the paths generated. |
n_jumps | Set the number of jumps for SS, WT and WF moves. |
rgen | Set the random number generator to use. |
seed | Set a seed for the random number generator. |
rescale_energy | Selects re-scaling of velocities. |
shooting_moves | Set the MC shooting moves in each ensemble. |
interface_cap | Set the cap value for subpaths generated by the WF move. |
sigma_v | Set standard deviations for the random velocity generation |
zero_momentum | Specify is momentum should be set to zero when shooting. |
Keyword aimless¶
Determines if we are to do aimless shooting or not. If this is set to
False
, then standard deviations for velocity generation can be set
by the keyword sigma_v.
- Default
- The default is
aimless = True
.
Keyword allowmaxlength¶
If True
, the maximum length for all paths are set to
the value given by the keyword maxlength
. If False
,
the maximum length is determined at random based on the length
of the current path we are shooting from.
- Default
- The default is
allowmaxlength = False
.
Keyword freq¶
This defines how often time reversal moves are performed:
E.g. if freq = 0.4
then 40% of the TIS moves
are time reversal. Note that if you are running a RETIS simulation,
then the percentage of TIS moves will be modified by the percentage
of swapping moves, e.g. the percentage of shooting moves will then
be given by .
- Default
- No default, this keyword must be specified.
Keyword interface_sour¶
This defines the position of the SOUR interface for Web Throwing. It HAS to be smaller then the interface defining the ensemble where WT is used. Note that an improper selection of interface_sour will hinder the sampling efficiency.
- Default
- No default, this keyword must be specified if WT is used.
Keyword high_accept¶
This select the version of Stone Skipping that is going to be used. Potential High Accept should always been choosen since it is more efficient. Note that the current implementation, due to detailed balance, DOES NOT ALLOW to have multiple shooting methods in the same ensemble.
- Default
- The default is
high_accept = True
.
Keyword maxlength¶
This determines the maximum length of the paths generated. Ideally, no paths should be longer than this value. A value too ristrictive can invalidate detailed balance.
- Default
- No default, this keyword must be specified.
Keyword n_jumps¶
The number of jumps for Stone Skipping, Wire Fencing and of web for Web Throwing.
- Default
- No default, this keyword must be specified if Stone Skipping, Wire Fencing or Web Throwing are going to be used.
Keyword rgen¶
Selection of the random number generator to use. The option allows the use of bias random number generator (mock) or an easy implementation of more advanced random number generators.
- Default
- The default is
rgen = rgen
.
Keyword rescale_energy¶
If this keyword is set to a number, then
the velocities are re-scaled so that the total energy is equal
to the given number. This is useful for performing NVE simulations.
If the keyword is set to False
, then the energies will not be
re-scaled.
- Default
- The default value is
rescale_energy = False
.
Keyword seed¶
This integer is a seed for the random number generator used in the TIS algorithm (e.g. when selecting a shooting point).
- Default
- The default is
seed = 0
.
Keyword shooting_moves¶
This list contains the flags that determines the shooting move to be used for each ensemble. Usable moves are ‘sh’ for shooting, ‘ss’ for Stone Skipping, ‘wt’ for Web Throwing and ‘wf’ for Wire Fencing.
- Default
- The default value is
[]
.
Keyword interface_cap¶
This defines the position of the cap interface for Wire Fencing. It HAS to be larger than the interface defining the ensemble where WF is used. Note that an inproper selection of interface_cap can hinder the sampling efficiency.
- Default
- No default.
Keyword sigma_v¶
This keyword can be used to set standard deviations for the
random velocity generation if the
keyword aimless is set to False
.
- Default
- The default value is
sigma_v = -1
.
Keyword zero_momentum¶
If this keyword is set to True
, then
the momentum of the system is set to zero after creating random
velocities for shooting. If False
, this is not done.
- Default
- The default is
zero_momentum = False
.