Hi Neal,
Thanks for your reply. I've attached below how I installed the arrow
R package on my system - first downloading and installing the C/C++
code, then installing the R package contained in this [arrow.git]
download.
refs/points:
1) https://github.com/apache/arrow/tree/master/r
2) https://arrow.apache.org/docs/developers/cpp/building.html
3) requires R version 3.6 or higher.
[1]:
git clone https://github.com/apache/arrow.git
cd arrow/cpp
mkdir release
cd release
[2]:
sudo cmake ../ -DARROW_COMPUTE=ON -DARROW_CSV=ON -DARROW_DATASET=ON
-DARROW_FILESYSTEM=ON -DARROW_JEMALLOC=ON -DARROW_JSON=ON
-DARROW_PARQUET=ON -DARROW_BUILD_TYPE=release -DARROW_WITH_BROTLI=ON
-DARROW_WITH_BZ2=ON -DARROW_WITH_LZ4=ON -DARROW_WITH_ZLIB=ON
-DARROW_WITH_ZSTD=ON -DARROW_EXTRA_ERROR_CONTEXT=ON -DARROW_PLASMA=ON
[3]:
sudo make install
[4]:
#then run this to pick-up the new libs in /usr/local/lib
sudo ldconfig
[5]:
# and make sure LD_LIBRARY_PATH and R_LD_LIBRARY_PATH contains /usr/local/lib
echo $LD_LIBRARY_PATH
echo $R_LD_LIBRARY_PATH
[6]:
#then try installing the R arrow package
cd ../../r
R -e 'install.packages(c("devtools", "roxygen2", "pkgdown", "covr"));
devtools::install_dev_deps()'
R CMD INSTALL .
#------------------------
I believe the code I wrote works... in the sense that the
value/address of the pointer passed is printed to screen - I also
tested this by modifying the code to include the libraries suggested
in your last email:
## compile c++ code
Sys.setenv("PKG_CXXFLAGS" = "-larrow_bundled_dependencies
-larrow_dataset -lparquet -larrow")
Running the R code, 'arrowTest.R', then generates:
> source('arrowTest.R')
Attaching package: ‘arrow’
The following object is masked from ‘package:utils’:
timestamp
in test
0x5652319be670
I guess my question was is what I'm doing correct? By this I mean from
the code i have written, is (or how is) it possible to print the
values of the arrow::Array, called 'aAPtr', that i've passed to
function 'test' - and similarity write values to aAptr?
Thanks for your time to read my email, and for your reply.
All the Best,
Colin Mclean.
Quoting Neal Richardson <neal.p.richard...@gmail.com> on Mon, 12 Oct
2020 08:09:44 -0700:
Hi Colin,
Does the code you shared run? If not, how does it fail?
One guess is that you're probably getting undefined symbols errors because
you need more than just -larrow. See
https://github.com/apache/arrow/blob/master/r/configure#L35 for others you
need, and depending on how you installed arrow, you likely also need
-larrow_bundled_dependencies.
Neal
On Mon, Oct 12, 2020 at 1:49 AM Colin McLean <cmcle...@staffmail.ed.ac.uk>
wrote:
Dear Arrow users,
I was wondering if anyone can help me understand how I can create an
arrow::Array object in R, then pass this into C++ (using the Rcpp
library) for both reading and writing too? Similar what is done using
the R bigmemory
(https://privefl.github.io/blog/Tip-Optimize-your-Rcpp-loops/) or
bigstatsr packages.
Kindest Regards,
Colin Mclean.
R script:
library(Rcpp)
library(arrow)
## compile c++ code
Sys.setenv("PKG_CXXFLAGS" = "-larrow")
sourceCpp("utils.cpp")
N = 10
X = arrow::Array$create(rep(0,N*N))
test( X$pointer() )
utils.cpp:
// define headers
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::depends(arrow)]]
#include <arrow/api.h>
#include <arrow/array.h>
#include <arrow/array/array_base.h>
#include <Rcpp.h>
#include <stdio.h>
#include <iostream>
#include <string>
using namespace Rcpp;
using namespace std;
// [[Rcpp::export]]
void test( XPtr<arrow::Array> aAPtr ){
cout << "read & write arrow::Array in test " << endl;
cout << aAPtr << endl;
}
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Scotland, with registration number SC005336.
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
