# read the SDSS-I Stripe 82 Variable Source Catalog
# read_catalog all varStripe82.dat
read_catalog 2
   #  $1 = subscript for data
   #  $2 = file name
 
   da $2
   lines 0 0

   define L "ra_$1 1 dec_$1 2 rExt_$1 3"
   define i 4
   foreach band <u g r i z> {
      foreach vec <Nobs med mu sig rms chi2 max runmax min runmin skew skewErr kurt kurtErr> {
         define L <$L $vec""$band""_$1 $i>
         define i $($i+1)
      }
   }
  
   read <$L>

   set uC = <6.27336 -1.60114 0.153714 -0.00656245 0.000105148>
   set gC = <2.13439 -0.540752 0.0517104 -0.00219396 3.48404e-05>
   set rC = <2.48331 -0.631346 0.0605023 -0.002575 4.10636e-05>
   set iC = <3.60719 -0.940377 0.0919942 -0.00398576 6.4533e-05>
   set zC = <8.06484 -2.16079 0.217055 -0.00967042 0.000161274>

   ## generate ugiz extinction from r extinction by using coefficients from SFD98
   set uExt_$1 = 1.87 * rExt_$1
   set gExt_$1 = 1.38 * rExt_$1
   set iExt_$1 = 0.76 * rExt_$1
   set zExt_$1 = 0.54 * rExt_$1

   # reddening correction
   set u_$1 = medu_$1 - uExt_$1
   set g_$1 = medg_$1 - gExt_$1
   set r_$1 = medr_$1 - rExt_$1
   set i_$1 = medi_$1 - iExt_$1
   set z_$1 = medz_$1 - zExt_$1

   # and colors
   set ug_$1 = u_$1 - g_$1
   set gr_$1 = g_$1 - r_$1
   set ri_$1 = r_$1 - i_$1
   set iz_$1 = i_$1 - z_$1

   unset uExt_$1 unset gExt_$1
   unset iExt_$1 unset zExt_$1
   unset fExt_$1 unset nExt_$1
   foreach band <u g r i z> {
      set xC = $band""_$1
      # mean photometric error fit
      set yC = $band""C[0]+$band""C[1]*xC+$band""C[2]*xC**2+$band""C[3]*xC**3+$band""C[4]*xC**4
      set rmsold$band""_$1 = rms$band""_$1
      # intrinsic variability
      set rms$band""_$1 = (rms$band""_$1**2 >= yC**2)?sqrt(rms$band""_$1**2 - yC**2):-99.99
      unset xC unset yC
   }