NLoptr failed to install on Mac: unable to load shared object - r

Question

I'm trying to install the package nloptr on Mac OS High Sierra in order to use many nice packages like lme4, and I'm using RStudio inside Anaconda, with R 3.4.2. I have also installed NLopt (downloaded from the NLopt website, not the development version. I have also installed Xcode command line tool. But I still can't install nloptr, and get this
Error: package or namespace load failed for ‘nloptr’ in dyn.load(file, DLLpath = DLLpath, ...):
unable to load shared object '/Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so':
dlopen(/Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so, 6): Symbol not found: _nlopt_add_equality_mconstraint
Referenced from: /Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so
Expected in: flat namespace
in /Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so
I already searched online for what to do, and did add the path where NLopt was installed to LD_LIBRARY_PATH in the /etc/ldpaths file, but I still get the same error. Yes, I have the same problem as in Trouble installing nloptr package on R 3.3.0, but I didn't find a solution that works there since the person who asked that question resolved it himself and I don't know what he meant when he said "installed as a root". Can anyone help?
Also, I got something like this when installing NLopt with CMake, and this happened to many different functions:
In file included from f77api.c:103:
./f77funcs.h:57:14: warning: 'nlopt_minimize_constrained' is deprecated
[-Wdeprecated-declarations]
*info = nlopt_minimize_constrained((nlopt_algorithm) *algorithm,
^
./nlopt.h:348:35: note: 'nlopt_minimize_constrained' has been explicitly marked
deprecated here
int maxeval, double maxtime) NLOPT_DEPRECATED;
^
./nlopt.h:320:43: note: expanded from macro 'NLOPT_DEPRECATED'
# define NLOPT_DEPRECATED __attribute__((deprecated))
^
Would this be why the library isn't loaded?
BTW, I have installed Rcpp and updated it. Rcpp works on my computer.
Update: I changed the default C and C++ compiler to clang4 downloaded from R project. I tried the installation again, and got a different error:
Error: package or namespace load failed for ‘nloptr’ in dyn.load(file, DLLpath = DLLpath, ...):
unable to load shared object '/Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so':
dlopen(/Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so, 6): Library not loaded: #rpath/libnlopt.0.dylib
Referenced from: /Users/lambda/anaconda3/lib/R/library/nloptr/libs/nloptr.so
Reason: image not found
Error: loading failed
I have tried to tell R where the library is by Sys.geteng(DYLD_LIBRARY_PATH = "/usr/local/lib"), but it didn't work. It actually appears that R does know where the shared library is, according to the messages I got from installation, but it just can't load it. Please help!

Answer 1

Never mind, I reinstalled Anaconda, and installed the standalone R and RStudio (not within Anaconda), and those packages all installed successfully. Maybe it's a bad idea to use the RStudio inside Anaconda.
Edit: For those who run into similar scenarios: I switched to Microsoft R Open (MRO), since I'm dealing a lot with linear algebra recently. Then when I tried to install nloptr in MRO, I got a similar error message that shared library failed to load because image not found. I reinstalled the CRAN R 3.4.3 and nloptr installed totally fine there. So I found where nloptr was installed in CRAN R 3.4.3 by .libPaths(), copied the nloptr folder to where MRO stores packages, and used the utility RSwitch to change the default version of R to MRO. Then I loaded nloptr in MRO, installed packages that depend on it, and used those packages; they worked fine. I don't know what's wrong with MRO that caused the error, but at least this worked.