converts (Q,E) values to Q values for diffraction instrument
   
    
    
    
    
  Syntax
Qm = sw_econtract(Q,Name,Value)
Description
Qm = sw_econtract(Q,Name,Value) converts  values in the phase
space into  values as it would appear when measuring it with via
neutron diffraction.
Input Arguments
Q- Input values in reciprocal space in the scattering plane in Å units, dimensions are .
 
Name-Value Pair Arguments
'E'- Energy transfer value in meV, default value is zero.
 'lambda'- Wavelength of the incident neutron beam in Å.
 'ki'- Momentum of the incidend neutron beam in Å, alternative
input to 
lambda. 'sense'- Scattering sense:
    
1detectors are on the right hand side from the incident beam direction, default.-1detectors are on the left hand side from the incident beam direction.