treekin − Calculate a macrostate dynamics of biopolymers
treekin [options] < foo.bar
computes a reduced dynamics of biopolymer folding by means
of numeric integration of a Markov process that generally
operates at the level of macrostates, i.e. basins of
attraction of the underlying energy landscape.
treekin expects a .bar file via stdin, and optionally a rates file in the current working directory. Both the .bar file and the rates file (default name is rates.out) can be obtained from barriers. In case of -m I option (default) the program needs just the rate file provided as standard input.
Print help and exit
Print version and exit
Make a state absorbing
Select method to build transition matrix: A ==> Arrhenius−like kinetics F ==> Full process kinetics (whole subopt) I ==> use input as a rate matrix (possible values="A", "F", "I" default=‘I’)
Method how to deal wih numerical errors in probability: I ==> Ignore H ==> Halt the program R ==> Rescale the probability (possible values="I", "H", "R" default=‘H’)
Start time (default=‘0.1’)
Stop time (default=‘1E12’)
Temperature in Celsius (default=‘37.0’)
Read only first <int> states (assume quasi−stationary distribution (derivation of others is = 0))
Set initial population of state <int> to <double> Can be given multiple times (NOTE: sum of <double> must equal 1) (example: "−−p0 2=1.0" − state 2 has initial population 100 percent)
Time scaling factor (for log time−scale) (default=‘1.02’)
Consider degeneracy in transition rates (default=off)
Use matrix−expontent routines, NO diagonalization (default=off)
Dump transition matrix U to a file mx.txt (and to binary mx.bin − not fixed yet) (default=off)
Dump transition matrix U to Mathematica−readable file mxMat.txt (default=off)
Assume binary rates input (default=off)
Calculate first passage times "all" − calculate all fpt’s(slow) <num> − calculate fpt’s to state <num> from all states
Recover from pre−calculated Eigenvalues and Eigenvectors (default=off)
Write recovery file containing Eigenvalues and Eigenvectors (default=off)
Show settings (default=off)
Name of the textfile containing the (barriers) rate matrix (NOTE: the rate matrix must have been print out with ’%10.4g’ per entry otherwise treekin will calculate crap) In case of −m I option (default), this is read from the standard input.
Verbose output (default=off)
Be silent (do not print out the output) (default=off)
File where to write first passage times (meaningfull only with −t option)
Filename where to print a visualization of rate graph (without file subscript, two files will be generated: .dot and .eps with text and visual representation of graph)
Do not diagonalize and iterate, just shorten input (meaningfull only with −n X option or −fpt option or −−visualize option) (default=off)
Maximal decrease in dimension in one step (default=‘1000000’)
Machine precision used by LAPACK routines (and matrix aritmetic) −− if set to negative number, the lapack suggested value is used (2*DLAMCH("S") ) (default=‘1E−15’)
Use old treekin computation where we add identity matrix to transition matrix. Sometimes less precise (maybe sometimes also more precise), in normal case it should not affect results at all. (default=off)
Rescale all rates to be higher than the minimal rate using formula "rate −> rate^(ln(desired_minimal_rate)/ln(minimal_rate))", where desired_minimal_rate is from input, minimal_rate is the lowest from all rates in rate matrix.
Rescale all rates by a hard exponent (usually 0.0<HR<1.0). Formula: "rate −> rate^(hard−rescale)". Overrides −−minimal−rate argument.
Write equilibrium distribution into a file.
Multiply rates with a constant number.
Turn all the warnings about underflow on. (default=off)
Typically, computation of a reduced dynamics based on the analysis of folding landscapes requires two steps: Elucidation of the landscape (topology) and − based on that − calculation of the reduced dynamics.
The first step involves computing the relevant properties of an energy landscape by barriers (see barriers(1) for details). The resulting .bar−file contains information on local minima, basins, saddle points as well as thermodynamic properties of the energy landscape. Additionally, the −−rates option in the below example triggers barriers to generate another output file (rates.out) containing the transition rates between all pairs of macrostates (ie. basins of attraction), calculated by summing over the corresponding microscopic rates.
barriers −−saddle −−bsize −−rates < foo.sub > foo.bar
In a second step, treekin is called with options to calculate the macrostate dynamics on the previously generated landscape by means of applying microscopic transition rates (option −m I):
treekin −−p0 2=1 < rates.out
In this example, the simulation starts with 100% of the initial population in macrostate 2, i.e. the second lowest minimum in the barrier tree (option −−p0 2=1). The transition matrix is computed from a set of microscopic rates, read from a rates file (as computed by barriers).
Generally, calculation of the macrostate dynamics by means of microscopic rates (option −m I) is consiberably more accurate than the simplified Arrhenius−like dynamics (option −m A).
Looking at the default output produced by treekin, there are two sections: Overall status information on the computation (marked by hash signs at the beginning of the line) are printed at the top. Below, the actual data is printed for each time step in (n+1) space−separated columns, where n is the number of investigated (macro)states. The first column lists the current time, whereas all remaining columns correspond to the population probabilities of individual (macro)states.
If you use this program in your work you might want to cite the following original papers:
W.A. Svrcek−Seiler, Ch. Flamm, I.L. Hofacker, P.F.
Efficient computation of RNA folding dynamics
J.Phys.A: Math.Gen. 37: 4731−4741 (2004)
Ch. Flamm, Ch. Heine, M.T. Wolfinger, G. Scheuermann, P.F.
BarMap: RNA folding on dynamic energy landscapes
RNA: 2010 16: 1308−1316 (2010)
Wolfinger, Marcel Kucharik, Ivo Hofacker, Christoph Flamm,
Andreas Svrcek−Sailer, Peter Stadler.
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