Table of Contents

The default is to search for local 3 point extrema. Using
**edge=** one can force it away from the edge, and using **pmin=** one can increase

the minimum number of points that need to be in the extreme

**in=**- Input file name [???]
**xcol=**- X-Column [1]
**ycol=**- Y-column [2]
**clip=**- Only consider points above this [0]
**delta=**- If a positive value is used, single peaks larger than this value on either side of this peak are reported. [0]
**pmin=**- [EXPERIMENTAL] Require the peak to
contain at least
**pmin**points. By default, only 3 are required, in which case a polynomial is fit (though this is an exact fit). By setting this higher, more points are required to be part of a peak which is then required to be monotonously decreasing.**edge=**Number of points near the edge to skip for a peak finder. For the simplest 3-point peak finder this should be at least 1. [1] **valley=t|f**- Also fit valleys, in which case the signal has to be below -clip. [Default: f]
**mean=t|f**- Use intensity weighted mean ? [Default: f]
**npeak=**- extract the Nth peak (N>0). If npeak=0, no extraction done. Other keywords will be ignored if a peak is ectracted for further analysis. [Default: 0]
**epeak=**- expand around the N-th peak extracted by npeak>0 by this factor. By default the segment around a peak is defined until the first point away from the peak will increase again. [Default: 1]
**nmax=**- max size if a pipe
[100000]

$ nemoinp 1:3 | tabmath - - ’-(2.2-%1)**2+10’ | tabpeak - 2.200000 10.000000Here is a pipeline extracting the first peak, fitting a gaussian to it, and plotting the data and residuals (in the PGPLOT driver the data will be in red, the residuals in green, and the fit in blue):

$ tabpeak spec.tab | tabnllsqfit - fit=gauss1d out=- | tee fit.log | tabcomment - | tabplot - 1 2,3,4 color=2,3,4 line=1,1 $ cat fit.log

Finding single peaks by setting an appropriate delta (related to a robust dispersion of the differences of the data):

$ tabtrend L1157-B1_109989__1.bstats.tab 2 | tabhist - robust=t ... Robust Mean Disp : 1.52724e-05 0.00640417 $ tabpeak L1157-B1_109989__1.bstats.tab delta=0.05 # X Y Ypeak Delta Delta 166.000000 1.591776 0.083979 0.087718 0.080239 286.000000 26.544859 25.062155 25.063228 25.061082 452.000000 1.838022 0.324911 0.324182 0.325639 ... 3524.000000 1.520718 0.229133 0.229248 0.229019 3810.000000 0.427400 -0.871551 0.870384 0.872717

28-May-2013V0.1 CreatedPJT 30-may-2013V0.2 added valley=PJT 23-mar-2022V0.4 added pmin=PJT 25-mar-2022V0.5 added edge=PJT 23-jan-2023V0.7 added npeak, epeak=PJT 25-may-20230.8 added delta=PJT