https://github.com/cran/fields
Tip revision: 219a7ad8ff302820e945ed6e9f8bef52f7fcbf36 authored by Douglas Nychka on 13 October 2019, 16:20:02 UTC
version 9.9
version 9.9
Tip revision: 219a7ad
compactToMatC.c
/*
c**** # fields is a package for analysis of spatial data written for
c**** # the R software environment .
c**** # Copyright (C) 2017
c**** # University Corporation for Atmospheric Research (UCAR)
c**** # Contact: Douglas Nychka, nychka@ucar.edu,
c**** # National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307-3000
c**** #
c**** # This program is free software; you can redistribute it and/or modify
c**** # it under the terms of the GNU General Public License as published by
c**** # the Free Software Foundation; either version 2 of the License, or
c**** # (at your option) any later version.
c**** # This program is distributed in the hope that it will be useful,
c**** # but WITHOUT ANY WARRANTY; without even the implied warranty of
c**** # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
c**** # GNU General Public License for more details.
*/
#include <R.h>
#include <Rinternals.h>
#include <R_ext/Arith.h>
#include <Rmath.h>
#include <float.h>
SEXP compactToMatC(SEXP compactMat, SEXP len, SEXP n, SEXP diagVal, SEXP lowerTri, SEXP upperTri)
{
int In, lTri, uTri, i, j, index;
double dVal;
double *cMat, *cans;
//cast R variables to C variables
In = INTEGER(n)[0];
lTri = INTEGER(lowerTri)[0];
uTri = INTEGER(upperTri)[0];
dVal = REAL(diagVal)[0];
cMat = REAL(compactMat);
SEXP ans = PROTECT(allocMatrix(REALSXP, In, In));
cans = REAL(ans);
//intialize entire array to zero DWN May-1-2016
for(i = 0; i < (In*In); i++) {
cans[i]= 0.0;
}
//set upper or lower triangle of output matrix
index = 0;
if(lTri) {
for(i = 0; i < In; i++) {
for(j=i+1; j < In; j++) {
cans[i*In+j] = cMat[index];
index++;
}
}
}
index = 0;
if(uTri) {
for(i = 0; i < In; i++) {
for(j=i+1; j < In; j++) {
cans[j*In+i] = cMat[index];
index++;
}
}
}
//set diagonal values of output matrix
for(i = 0; i < In; i++) {
cans[i*In + i] = dVal;
}
UNPROTECT(1);
return ans;
}