hist.ab {sjemea} | R Documentation

## Histogram routines to help compute the cross-correlation between a pair of spike trains.

### Description

For a pair of spike trains, TA (train a) and TB, these related routines return the count of the number of spikes in B that occur within some time window [-tmax,tmax] of a spike in A. For histbi.ab, we return a histogram of dt values from [-tmax,tmax]. For hist.ab, we ignore the sign of each dt and just return a histogram in the range [0,tmax]. Finally, for count.nab, we just return the number of dt values found in the range [-tmax,tmax], rather than binning dt into a histogram.

### Usage

    hist.ab(ta, tb, tmax, nbins)
    histbi.ab(ta, tb, tmax, nbins)
    count.nab(ta, tb, tmax)

### Arguments

`ta` | Vector of spike times, sorted such that lowest is first.
`tb` | Vector of spike times, sorted such that lowest is first.
`tmax` | maximum time (in seconds) to bin
`nbins` | Number of bins in the histogram. For histbi.ab, each bin is of width (2*tmax)/nbins. For hist.ab, each bin is (tmax)/nbins wide.

### Value

`hist.ab` returns a histogram of counts ignoring sign. `histbi.ab` returns a histogram of counts respecting sign. `count.nab` returns the number of dt values.

### METHOD

For the histogram routines, each bin is of the form [low, high), with the exception of the last bin (for +tmax), which is of the form [tmax-binwid, tmax]. By assuming the spikes are ordered lowest first, the number of spike comparisons is greatly reduced, rather than comparing each spike with A with each spike in B.

### References

No references here.

### See Also

Nothing else yet...

### Examples

    stopifnot(isTRUE(all.equal.numeric(
      histbi.ab(c(0), c(-2, -2, 0, 0, 1, 1,1, 1.8,2), tmax=2, nbins=4),
      c(2,0,2,5),
      check.attributes=FALSE)))
    stopifnot(identical(TRUE, all.equal.numeric(
      hist.ab(c(0), c(-2, -2, 0, 0, 1, 1,1, 1.8,  2), tmax=2, nbins=4),
      c(2,0,3,4),
      check.attributes=FALSE)))

    test.hist.ab()

    ## Not run:
    test.histograms.versus.r()
    test.count.hist.nab()
    test.count.hist.nab(s)
    test.count.hist2.nab(s)
    ## End(Not run)

[Package sjemea version 0.20 Index]