How can I find the peak prominence of a specific set of data points?

Hello,

I am creating a code that takes a large section of data (~10^8 data points), divides the data into sections, and finds the maximum of each section. My result of that is this:

if PosPks =

   15.2751   20.4965   37.7687   44.0004   13.0303   14.1818   19.9465   38.8933   15.9228   46.9948   13.3018   17.3097   42.3216   12.9795   16.8526   43.5099   33.7775

PosIdxTick =

Columns 1 through 14

     4517849     9508124    12045698    19027549    19200001    28629574    33522452    34269688    43200000    44231017    52789827    57577043    59147043    66969600

Columns 15 through 17

    71915940    76776514    76800001

(I have the value and location of the maxima). My next step is to find which of these maxima has a peak prominence of 12.

I know that the function

findpeaks(data,'MinPeakProminence',12)

could be used to find the peaks in my data that have a minimum prominence of 12, but I have ~10^8 data points, and that would take a long time for findpeaks to go over and do its work. I already have the maximum values I want (except it's an over-inclusive set of them), now I just want to extract the ones that have a peak prominence of 12 or higher. The problem is, I don't know how to find the peak prominence of a point. It is necessary to have surrounding data to determine the peak prominence.

So, is there a faster way to find the peak prominence of just these points?

Thank you, George