amu_trj_get_dt

#!/bin/bash
mdo=${1:-mdout}
md=${2:-mdcrd.nc}
unit=${3:-10}

function usage() {
   echo "usage:"
   echo "`basename $0` [mdout] [mdcrd.nc] [unit_in_ps]"
   echo "default unit of output is 10 ps"
}

[ $AMU_HOME ] || { echo  "AMU_HOME not set." ; exit ; }
source $AMU_HOME/ambermd_util.bash


for file in $mdo $md ; do 
if [ ! -f "$file" ] ; then
    echo "`basename ${0}` error: file `readlink -m $file` not found." >&2
    usage
    exit 1
fi
done

interval=`sed -n "s/^.*\<ntwx\>\s\+=\s\+\([1-9][0-9]*\).*$/\1/p" $mdo`
dt=`sed -n "s/^.*\<dt\>\s\+=\s\+\([0-9]\+\.[0-9]*\).*$/\1/p" $mdo`
frame_time_unit=""
newinterval=""
stride=""
if [ -n "$interval" ] ; then
      frame_time_unit=`python3 -c "print( int($interval * $dt / $unit) )"`
      if [ `python3 -c "if $frame_time_unit > 0: print(1)"` ] ; then 
#        frame_time_unit=$(echo "$frame_time_unit" | cut -d'.' -f 1 )
        echo "$frame_time_unit * $unit ps" 
      else
        echo "`basename ${0}` error: dt == 0. Malformed mdout file: `readlink -m $mdo`" >&2
        exit 1
      fi
else
    echo "`basename ${0}` error: interval == 0 or missing. Malformed mdout file: `readlink -m $mdo`" >&2
    exit 1
fi