If a pw_job nmr_shift entry is encountered, paratec computes the local diamagnetic susceptibility. The variable
nmr_q 0.001
sets the 
(in cartesian coordinates), which determines the
periodicity of the applied external field.
Default: nmr_q 0.01
Set the output flag nmrshift to get a plot of the susceptibility (section 13).
If a line
checkpoint nmr
is entered, the code will checkpoint the NMR shift calculation after each kpoint. You can recover from a crash by giving an input_flags of chkptchi.
IMPORTANT: Right now, the NMR shift can only be computed for INSULATORS. You have to set number_bands to contain only the VALENCE BANDS, or else the result will be wrong.