Options Settings

Description

Allow the user to set and examine a variety of options which affect the way in which R computes and displays sparse matrix results.

Usage

spam.options(...)

spam.getOption(x)

Arguments

Details

Invoking spam.options() with no arguments returns a list with the current values of the options. To access the value of a single option, one should use spam.getOption("eps"), e.g., rather than spam.options("eps") which is a list of length one.

Internally, the options are kept in the list .Spam.

Value

For spam.getOption, the current value set for option x, or NULL if the option is unset.
For spam.options(), a list of all set options sorted by category. For spam.options(name), a list of length one containing the set value, or NULL if it is unset. For uses setting one or more options, a list with the previous values of the options changed (returned invisibly).

Options used

A short description with the default values follows.

eps=.Machine$double.eps:

values smaller than this are considered as zero. This is only used when creating spam objects.

drop=FALSE:

default parameter for drop when subsetting

printsize=100:

the max number of elements of a matrix which we display as regular matrix.

imagesize=10000:

the max number of elements of a matrix we display as regular matrix with image or display. Larger matrices are represented as dots only.

trivalues=FALSE:

a flag whether to return the structure (FALSE) or the values themselves (TRUE) when returning the upper and lower triangular part of a matrix.

cex=1200:

default dot size for image or display.

dopivoting=TRUE:

default parameter for "solve" routines. FALSE would solve the system without using the permutation.

safemode=c(TRUE,TRUE,TRUE):

The logicals are determine (1) verify double and integer formats when constructing spam objects (2) quick sanity check when constructing sparse matrices (3) testing for NAs in Fortan calls. TRUEs are safer but slightly slower. The most relevant speedup is the second flag.

cholsymmetrycheck=TRUE:

for the Cholesky factorization, verify if the matrix is symmetric.

cholpivotcheck=TRUE:

for the Cholesky factorization, when passing a permutation, should a minimum set of checks be performed?

cholupdatesingular="warning":

for a Cholesky update, what happens if the matrix is singular: "warning" only and returning the not updated factor, "error" or return simply "NULL".

cholincreasefactor=c(1.25,1.25):

If not enought memory could be allocated, these are the steps to increase it.

nnznearestdistnnz=c(400^2,400):

Memory allocation parameters for nearest.dist.

nearestdistincreasefactor=1.25:

If not enought memory could be allocated, this is the step to increase it.

Author(s)

spam.options is essentially identical to sm.options.

See Also

print, display, image, upper.tri, chol, nearest.dist, etc.

Examples

op <- spam.options()

# two ways of representing the options nicely.
utils::str(op)
noquote(unlist(format(op)) )

smat <- diag.spam( 1:8)
smat
spam.options( printsize=49)
smat

# Reset to default values:
spam.options( eps=.Machine$double.eps, drop=FALSE,             
   printsize=100,  imagesize=10000,   cex=1200, 
   trivalues=FALSE,   safemode=c(TRUE,TRUE,TRUE), 
   dopivoting=TRUE,       cholsymmetrycheck=TRUE,  
   cholpivotcheck=TRUE, cholupdatesingular="warning",
   cholincreasefactor=c(1.25,1.25),
   nearestdistincreasefactor=1.25,
   nearestdistnnz=c(400^2,400)     )