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 Purpose: Calculates the time evolution of an expectation value.
 Usage  : oppsi [-op -f -i -o -t -n -skip -dp -pt -w -ver -h -?] [operator].


Options : 
 -op FILE : The operator is read from file FILE rather than from ./oper

 -f FILE : The wavefunction is read from file FILE rather than from ./psi
           The string FILE may be a relative or a full path-name.
 -o FILE : The output is written to file FILE.pl rather than to ./expect.pl
           The string FILE may be a relative or a full path-name.
           If FILE=no, i.e. "-o no", no output file will be opened,
           and the output is directed to screen.
 -i DIR : data is stored in directory DIR

 -t tfin : The expectation values are computed only up to time=tfin.
 -n step : Compute the property only every step-th output.
 -skip nskip : Skip the first nskip wavefunctions.
 -dp : Wavefunction saved double precision
 -w      : An existing property file is overwritten.
 -DB PATH : Sets path to DD DB relative to current location. Default ..
 -ver    : Version information about the program.
 -h      : Print this help text. 
 -?      : Print this help text. 

 The argument operator is the name of the operator, as specified in an
 HAMILTONIAN-SECTION_xxx, for which the expectation value is required.
 If no argument is given, the user is prompted for the missing argument.
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