Fri, 1 Jan 1999 22:46:18 -0700 (MST)
I've been celebrating the holidays by (finally) getting to the port of our
S+ NetCDF routines to R, which I'm trying to make into a library. At the
moment, there are two issues I'd appreciate advice on:
1. Is support for mode "single" data planned anytime soon in R? A lot of
our NetCDF files contain "single" data and having to coerce into "double"
will increase the use of R memory drastically (and slow things down).
2. Is there support for "pointer to pointer" arguments to .C? NetCDF files
contain the data attributes, which aren't known until the files are read.
Our S+ code defines a dummy variable for the data dimensions, which are
redefined (calling "S_alloc") and set within the C code once they are known.
The appended example works in S+ using the pointers= argument in .C.
Is there a way to do this in R?
int *ncid_p, /* NetCDF file id. File is left open */
int *var_id_p, /* variable id */
long **varlen, /* Length of variable, along each dimension */
long *ndims_r, /* number of dimensions in variable */
/* This argument is created automatically by S+'s
.C for pointers=T variables */
char **vartype) /* character string describing S object type */
*varlen = dimval = (long *)S_alloc(ndims,sizeof(long));
vardims <- integer(0) # Length of each dimension
vartype <- "" # "integer","single","double" etc
# get info about variable
cdf <- .C("inquire_varid",
cdfid = cdfid,
varid = varid,
vardims = vardims,
vartype = vartype,pointers=c(F,F,T,F))
P.S. I'm using R 0.64 under Redhat Linux 5.2.
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