Inversion parameters (INVPAR namelist)

Switches (usually 0 = off, 1 = on)

invr -  calculate  partial  derivatives  of  the  selected  model  
   parameters and write these to the file i.out (default: 0)

Other inversion parameters

ivray - an  array of  non-zero integers  corresponding to the  ray 
   groups listed in the  array ray used  to identify the  type of 
   arrival in the file tx.out if itxout=2 or 3 and to allow for the 
   appropriate comparison with the  observed travel times  in the 
   file tx.in if invr=1 or i2pt>0

ximax - the maximum allowable distance (km) between the nearest ray
   end point and an observed seismogram location for one of the rays
   used to interpolate the partial derivatives and travel time at
   that observed seismogram location (default: (xmax-xmin)/20)

ttunc - uncertainty of the calculated travel times  (s) written to 
   the file tx.out if itxout>0 (default: 0.01)

bndunc, velunc -  estimated uncertainty of  the depth  of boundary 
   nodes (km)  and velocities  (km/s) written  to the  file i.out  
   (defaults: 0.1, 0.1)