Mark, the documentation falsely assumes all computers have 32 bits
integers; yours seems not -- compare the .BigInt with sqrt(2^64). To see
how the point pairs are obtained, look at:
> gstat:::as.data.frame.variogramCloud
function (x, row.names, optional, ...)
{
.BigInt = attr(x, ".BigInt")
x$left = x$np%%.BigInt + 1
x$right = x$np%/%.BigInt + 1
x$np = NULL
class(x) = "data.frame"
x
}
so the .BigInt attribute is the divisor; 1 is added because the arrays
are set up in the C code, starting at 0.
--
Edzer
Mark Connolly wrote:
gstat reference states
If cloud is TRUE: an object of class variogramCloud, with the field np
encoding the numbers of the point pair that contributed to a variogram
cloud estimate, as follows. The first point is found by the integer
division of np by 2^16, the second point by the remainder of that
division.
For
Classes ‘variogramCloud’ and 'data.frame': 3275 obs. of 6 variables:
$ np : num 8.59e+09 8.00 8.59e+09 1.29e+10 1.29e+10 ...
$ dist : num 18.8 79.2 77.8 78.7 100.1 ...
$ gamma : num 0.781 0.845 12.903 5.611 0.344 ...
$ dir.hor: num 0 0 0 0 0 0 0 0 0 0 ...
$ dir.ver: num 0 0 0 0 0 0 0 0 0 0 ...
$ id : Factor w/ 1 level "var1": 1 1 1 1 1 1 1 1 1 1 ...
- attr(*, "direct")='data.frame': 1 obs. of 2 variables:
..$ id : Factor w/ 1 level "var1": 1
..$ is.direct: logi TRUE
- attr(*, ".BigInt")= num 4.29e+09
v[1,] yields:
dist gamma dir.hor dir.ver id left right
1 18.75474 0.78125 0 0 var1 6 3
v$np[1] %/% 2^16 yields:
131072
Which is != 6
Am I misinterpreting the documentation?
--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics [email protected]
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