Description Usage Arguments Details Value Examples
Computate a neighbourhood matrix using spatial coordinates.
1 2 3 4 5 6 7 8 9 10 | ## S4 method for signature 'data.frame'
calcW(object, range, method = "euclidean", upper = NULL,
format = "dgCMatrix", row.norm = FALSE, spatial_res = rep(1,ncol(object)),
calcBlockW = FALSE)
## S4 method for signature 'MRIaggr'
calcW(object, range, spatial_res = c(1,1,1), num = NULL,
hemisphere = "both", subset = NULL, upper = TRUE, format = "dgCMatrix",
row.norm = FALSE, calcBlockW = FALSE,
verbose = optionsMRIaggr("verbose"), update.object = FALSE, overwrite = FALSE)
|
object |
a data.frame containing the coordinates of the observations or an |
range |
only distances smaller than |
method |
the distance measure to be used. character. This must be one of |
spatial_res |
a dilatation factor for the coordinates. positive numeric vector of size 3. |
num |
the slices to use. numeric vector or |
hemisphere |
the hemisphere to use. character. |
subset |
the subset of observations to use. positive integer vector or |
upper |
should the entire matrix ( |
format |
the format of the output. Could be |
row.norm |
should the resulting matrix be row-normalized ? |
calcBlockW |
should the partition into disjoint spatial blocks of sites be computed ? logical. |
verbose |
should the execution of the function be traced ? logical. |
update.object |
should the resulting neighbourhood matrix be stored in |
overwrite |
if a neighbourhood matrix is already stored in |
These functions require to have installed the Matrix and the spam package to work.
ARGUMENTS:
Information about the num
argument can be found in the details section of initNum
.
The range
argument cooresponds to the delta
argument of the nearest.dist
function from the spam package.
Information about the hemisphere
argument can be found in the details section of selectContrast
.
The row.norm
argument is ignored if format
is set to "spam"
.
FUNCTION:
This function relies on the nearest.dist
function of the spam package.
Each of the num
, hemisphere
and subset
argument define a subset of the total set of observations.
It is the intersection of all these three subsets that is extracted.
Invisible. A list containing :
[[W]]
: a spam or dgCMatrix object.
[[block]]
: the output of the calcBlockW
function if calcBlockW
is set to TRUE
, NULL
otherwise.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | ## load a MRIaggr object
data("MRIaggr.Pat1_red", package = "MRIaggr")
#### 1- data.frame method ####
coords <- selectCoords(MRIaggr.Pat1_red, num = 1:3, hemisphere = "lesion")
## full W
W <- calcW(object = coords, range = sqrt(2))$W
W[1:10,1:10]
table(spam::rowSums(W))
## full W normalized by row
W <- calcW(object = coords, range = sqrt(2), row.norm = TRUE)$W
W[1:10,1:10]
table(spam::rowSums(W))
## upper W
W <- calcW(object = coords, range = sqrt(2), upper = TRUE)$W
W[1:10,1:10]
#### 2- MRIaggr method ####
## compute W (regular lattice)
W <- calcW(MRIaggr.Pat1_red, range = sqrt(2), upper = NULL, num = 1:3, hemisphere = "lesion")$W
table(spam::rowSums(W > 0))
## compute W (irregular lattice)
W <- calcW(MRIaggr.Pat1_red, range = sqrt(2 * 1.875^2), upper = NULL, num = 1:3,
hemisphere = "lesion", spatial_res=c(1.875, 1.875, 6))$W
table(spam::rowSums(W > 0))
|
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