collect.energy: finds a region the under the highest point in a 1-D landscape...
In landmarkacoustics/SoundPoints-R: an R version of the SoundPoints algorithm

Description Usage Arguments Details Value Author(s) See Also Examples

goes to the max of the input vector, then walks out in either direction until the user-specified amplitude sum is achieved

1	collect.energy(spk, desired.sum)

`spk`	a vector that corresponds to a peak trace.
`desired.sum`	the area under the curve that you are looking for

this function assumes all of spk >= 0, and will perform oddly if any values are negative.

a vector with three entries:

`lo`	the index of the beginning of the region (inclusive)
`hi`	the index of the end of the region (inclusive)
`total`	the sum of the heights within the region

Benjamin N. Taft ben.taft@landmarkacoustics.com

spectrum collect.absolute.energy

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (spk, desired.sum) 
{
    ends <- rep(match(max(spk), spk), 2)
    N <- length(spk)
    total <- 0
    current.step <- 1
    while (total < desired.sum) {
        temp.next <- c(ifelse(ends[1] > 1, spk[ends[1] - 1], 
            -Inf), ifelse(ends[2] < N, spk[ends[2] + 1], -Inf))
        now <- 1 + (temp.next[1] < temp.next[2])
        if (is.infinite(temp.next[now])) 
            break
        height <- spk[ends[now]] - temp.next[now]
        width <- ifelse(height > 0, current.step, 1)
        ends[now] <- ends[now] + ifelse(now == 1, -1, 1)
        total <- total + width * height
        current.step <- current.step + 1
    }
    return(c(ends, total))
  }