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Published byCamilla Fletcher Modified over 9 years ago
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Amber 10 Tutorial Minimization in Sander
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Minimization It is important to do a quick read of pg. 21 and the start of pg 22 of Amber10 Manual.pdf. These 2 pages show the syntax of how to run the sander command function. All page numbers here will refer to the “Amber10 Manual.pdf”
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minimization.sh The code below is the code to run a minimization in sander. It will be described in detail in the next few slides. #Running minimization for lys w/ H20 cat min.in #5000 steps of minimization &cntrl maxcyc=5000,imin=1,ntx=1,ntwx=0,ntwv=0,ntwe=1, ncyc=20,ntmin=1,drms=1.0E-4,ntb=1,cut=12.0, igb=0, / EOF echo 'begin bnr minimization' >> timer.dat date >> timer.dat bnra=/home/saguaro/Quickgo/amber10tutorial sander -i min.in -o min.out -p $bnra/bnrwh2o.top -c $bnra/bnrwh2o.crd -r min.rst -e min.ene date >> timer.dat echo 'end bnr minimization' >> timer.da t
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Min.in maxcyc = 5000pg 27 – maximum number of cycles the minimizations will run before it stops – like NSTEP in saguaro imin = 1pg 23 – 1 means do minimization and no molecular dynamics – same as imin in saguaro except an analysis option, imin = 5 ntx = 1pg 24 – reads in formatted (i.e. not binary) coordinates without velocites – similar to iCRD in saguaro, but NOT the same. ntwx,ntwv,ntwe = #pg 25,26 – these denote the number (#) of steps between writing the positions (x), velocities (v), or energies (e) of the run. – minimization doesn’t write any of these out.
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Min.in ntmin = 1pg 27 – applies the stepest descent algorithm to the minimization run for ncyc then switches to the conjugate gradient. ncyc = 20pg 27 – 20 steps before the run switches to conjugate gradient. drms = 1.0E-4pg 27 – the run will stop when the root-mean-square of the coordinates of the gradient is less than this value. Units are in kcal/(mol-angstrom) ntb = 1pg 35 – this is periodic boundary conditions (constant volume) – this is the same as iPBC in saguaro cut = 12.0pg 35 – non-bonded cutoff in angstroms. I should have used 8 here because this is explicit water. igb = 0pg 36 & 54 – 0 turns off generalized born. Unlike saguaro there are a lot of gb types to choose from
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Minimization An example run of this can be found on saguaro@dnaseq in the directory ~/Quickgo/amber10tutorial/bnrMD/minimize/
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