2017-11-14 22:50:54 -0500 received badge ● Student (source) 2017-11-14 11:55:42 -0500 commented question CoxeterGroup / coxeter3 trouble actually, yeah, that did work! That said, there's STILL no mention of Coxeter3 in dir(sage.libs), but suddenly everything works. I did not know the incantation "sage -b". Thanks so much! 2017-11-08 11:57:40 -0500 received badge ● Editor (source) 2017-11-06 15:34:09 -0500 commented question CoxeterGroup / coxeter3 trouble aha! you are right, coxeter3 is NOT in dir(sage.libs)! I've done something wrong in the installation process, then. Thank you! Do you know whether there is a clear set of instructions, somewhere, for how to install an optional spkg? I had a lot of difficulty looking this up in the manual. 2017-11-04 10:16:49 -0500 asked a question CoxeterGroup / coxeter3 trouble I'm having some trouble using the optional coxeter3 package - can somebody see what I'm doing wrong? I just built a clean version of sage 8.0, freshly cloned from github, on my ubuntu machine. Then I ran sage -i coxeter3  as one does; it installed with no errors. It seems to have worked: installed_packages(), for instance, has the line  'coxeter3': '1.1',  and there's a sage.libs.coxeter3 module in the namespace. But, for instance, when I try to use coxeter3 as per the instructions on the Coxeter Groups page in the sage documentation (can't provide a link as karma is too low), I get a RuntimeError:  sage: W = CoxeterGroup(["A",2], implementation='coxeter3') --------------------------------------------------------------------------- RuntimeError Traceback (most recent call last) in () ----> 1 W = CoxeterGroup(["A",Integer(2)], implementation='coxeter3') /home/bjy/build/sage/local/lib/python2.7/site-packages/sage/combinat/root_system/coxeter_group.pyc in CoxeterGroup(data, implementation, base_ring, index_set) 142 from sage.libs.coxeter3.coxeter_group import CoxeterGroup 143 except ImportError: --> 144 raise RuntimeError("coxeter3 must be installed") 145 else: 146 return CoxeterGroup(cartan_type) RuntimeError: coxeter3 must be installed  Any help is appreciated! I don't know enough even to start troubleshooting, though I tried the usual kinds of google searches and such. =============== Updates: 'coxeter3' ISN'T in dir(sage.libs) for me, so it looks like the package didn't "fully install", or something. It's entirely possible that I didn't install the package correctly; I still haven't managed to find a clear set of intallation instructions. I did try doing "make build" after 'sage -i coxeter3" as per FrédéricC's comment; my computer churned away for a while, but ultimately it didn't change anything. Maybe I can more precisely target my question. Where can I find a clear set of instructions for how to install the optional Coxeter3 spkg in a current sage build? ================ Update 2: So, apparently the ting to do is to say sage -f Coxeter3 sage -b  whereupon everything works - except that dir(sage.libs) still has no mention of Coxeter3, so I'm not sure what's up with that. For those following along at home: as far as I can see, the first command causes Coxeter3 to be forcefully reinstalled, regardless of what I did beforehand to mess things up; presumably the "-b" in the second command is "build" in some capacity. Thanks folks!