can anyone explain the folllowing function in ads?

Spectrum=20*log(mag(IF_P-IF_N) +1e-20)
#define new variable as output differnece
IF_d=mix(Spectrum,{-1,1},Mix)
#generate the spectrun output at frequency F2-f1?
IMD_d=mix(Spectrum,{-2,2},Mix)
#generate the spectrun output at frequency 2*F2-2*f1?
V_gain_d=IF_d-Vinput_dB
#gain of circuit at IF frequency(F2-F1)
LOfreq1=indep(mix(LO_P[0,::],{1,0},Mix[0,::]))
what is the above expression? I totally can not understand it
what is LO_P[0,::]?
RFfreq=indep(mix(LO_P[0,::],{0,1},Mix[0,::]))

IFfreq=min(mix(freq[0,::],{-1,1},Mix[0,::]))

Spectrum_zoomed=mix(Spectrum[VinputIndex,::],zoomed_indices,Mix[VinputIndex,::])
what is Spectrum[VinputIndex,::]?
how to explain expression Spectrum_zoomed?
zoomed_indices=[{0,0},{-1,1},{-2,2},{-3,3}]
what does this mean?
vs(Spectrum[VinputIndex,::],freq[VinputIndex,::])
what does this mean too?
thanks a lot