The Seismic Laboratory for Imaging and Modeling (SLIM) from the department of Earth and Ocean Sciences (EOS) at the University of British Columbia (UBC) is happy to announce the creation of its user folder in RSF. Current contributions are:
sfthr Threshold float/complex inputs given a constant/varying threshold level.
Methods available:
– soft
– hard
– non-negative Garrote (nng)
sfsort Sort in ascending/descending order absolute value entries of a float/complex vector.
More functions that come out of our industry-supported research will be released in the near future.

At the suggestion of Gilles Hennenfent, certain RSF programs now recognize unit1=, unit2=, etc keywords in addition to label1=, label2=, etc. This allows for more control on physical dimensionality.
Here is an example of having some fun with physical units:

1. Create some data.
   bash$ sfspike n1=100 n2=100 > spike.rsf
   bash$ sfin spike.rsf
   spike.rsf:
   in="/var/scratch/spike.rsf@"
   esize=4 type=float form=native
   n1=100         d1=0.004       o1=0          label1="Time" unit1="s"
   n2=100         d2=0.1         o2=0          label2="Distance" unit2="km"
   10000 elements 40000 bytes
   

2. Convert kilometers to feet:
   bash$ sfunits unit2=ft spike.rsf >> spike.rsf
   Converting "km" to "ft" on axis 2
   bash$ sfin spike.rsf
   spike.rsf:
   in="/var/scratch/spike.rsf@"
   esize=4 type=float form=native
   n1=100         d1=0.004       o1=0          label1="Time" unit1="s"
   n2=100         d2=328.084     o2=0          label2="Distance" unit2="ft"
   10000 elements 40000 bytes
   

   sfunits is a new script for unit conversion. It relies on the Unix units utility.

3. Apply 2-D FFT transform.
   bash$ < spike.rsf sffft1 | sffft3 axis=2 > fft.rsf
   sffft3: padded to 200
   bash$ sfin fft.rsf
   fft.rsf:
   in="/var/scratch/fft.rsf@"
   esize=8 type=complex form=native
   n1=55          d1=2.31481     o1=0          label1="Frequency" unit1="1/s"
   n2=200         d2=1.524e-05   o2=-0.001524  label2="Wavenumber" unit2="1/ft"
   11000 elements 88000 bytes
   

4. Transform back.
   bash$ < fft.rsf sffft3 axis=2 inv=y | sffft1 inv=y > back.rsf
   bash$ sfin back.rsf
   back.rsf:
   in="/var/scratch/back.rsf@"
   esize=4 type=float form=native
   n1=100         d1=0.00400001  o1=0          label1="Time" unit1="s"
   n2=100         d2=328.084     o2=0          label2="Distance" unit2="ft"
   10000 elements 40000 bytes
   

Warning: this is a substantial change that affects many programs and examples. Please report any problems.