@tomleslie wrote:

Using "%m" gives output in Maple ".m" format, and it seems(?) to be identical to the results when using save(expr,filename) when 'filename' has a '.m' extension.

As far as I can tell, this use of save with unnamed expressions is undocumented. When E is a named expression, there is a slight difference between

save E, filename;

and

fprintf(filename, "%m", E);

The difference is that with the save, the name E is also stored, so that the saved expression is equivalent to E:= <value of E> rather than just <value of E>.

The only other place I can find a reference to 'dotm' is as an option in the MapleTA[ToString] command.

That command (without the dotm option) looks like a useful way to put an expression into a mostly human-readable but also machine rereadable form.

@acer Oh, how boring and cryptically documented! I thought that this was an exciting new way to write directly to worksheets. But actually it's just a patch to maintain backward compatibility. I see that if

p:= 1+x+x^2:

then

sprintf("%m", p) <> sprintf("%Zm", p).

Do you have any example where one would need to use this? Are expressions in worksheets stored in .m (or .Zm) format?

What you describe is totally normal. Integer linear programming problems are hard. You have a lot of constraints and, more significantly, a huge number of variables. I only looked at your worksheet briefly, but it looks like 18^3 = 5832 variables. Try relaxing the assume= binary constraint to all variables being between 0 and 1. In other words, make it a linear program. You may get an answer that is binary anyway.

You should practice on a smaller version of your problem.

@Milos Bilik If you extract specific columns, as in M[2.., 4], M[2.., 7], then they already are Vectors; no further conversion is needed.

@Markiyan Hirnyk 

The NonIsomorphicGraphs command is much more useful for this purpose than the IsIsomorphic command that I used. Unfortunately, neither of these commands is listed on the help page ?GraphTheory. If they had been, I would've used NonIsomorphicGraphs.

@Milos Bilik 

If M is the Matrix, then do the extraction as M[2.., [4,7]]. That says "rows 2 to the end, columns 4 and 7". Converting dates to floating point is probably more complicated. I'd need to see the date format to see what you mean.

Your graph is very likely a cluster graph. Look up "graph clustering" in Google. You will need to use an algorithm for identifying the clusters. I don't know if there is any algorithm for this already in GraphTheory. Once the clusters are identified, it is easier to draw a meaningful representation of  the graph. Do a Google image search on "cluster graph" to see what I mean.

@aamirkhan 

kernelopts(version);

@LaineTrance 

RationalRoots:= proc(f::And(polynom(integer), satisfies(f-> nops(indets(f,name))=1)))
uses NT= numtheory;
local x:= indets(f,name)[], p, q, r;
     r:= select(
          r-> eval(f, x= r) = 0,      
          {0, seq(seq([p/q, -p/q][], p= NT:-divisors(tcoeff(f))), q= NT:-divisors(lcoeff(f)))}
     );
     if r = {} then printf("No rational roots") end if;
     r
end proc:

I also can run your worksheet without error.

@Doug Meade Maple's dsolve does support the numerical solution of BVPs. For example,

dsolve({diff(y(x),x$2) - y(x) = sin(x), y(0)=0, y(1)=0}, numeric);

     proc(x_bvp) ... end proc

@acer wrote:

Carl, you wrote that the problem was also exhibited when the problematic subsection was not empty. When it was not empty did it have a title?

There probably was at least a moment when it had a body but no title:  When trying to delete the subsection, I probably deleted the title first and then the body. But I've also probably done that many other times without it causing a problem.

What happened to the Answers to this Question? This was important material that I need to refer back to! If you look at the number of Replies in the Active Conversations list, it says that there are 10.

@John Fredsted Thank you. It works.

@AndreMenezes 

I think that I see where you're going with this. Maple's ability to convert between formal products and formal sums is very limited. You're better off just defining the log-likelihood function straight away.

Download Likelihood.mw