I am (again) trying to get Maple to do some parallel work; using the Threads package.

My actual problem involves a vector function with 6 elements, acting on 6-vectors. Each element of the output vector is calculated as a high-order polynomial of all 6 input elements. The whole thing is a map that I want to iterate. I plan to evaluate each of the 6 functions in a separate thread (the input vector of course is the same for all six) and then put the results together in a Vector, to be used as input for the next iteration.

Facing difficulty I finally wrote myself a little toy program to check out the basic mechanism. Here it is:

restart;
                "Maple Initialization loaded..."
with(Threads):
f:=x -> 1+x^2;
                                       2
                        f := x -> 1 + x
x:=0:
tt:=time[real]():

for i from 1 to 10 do
  id:=Create(f(x),y):
  Wait(id):
  x:=y:
  y:='y':
end do:

time[real]()-tt;
                             0.018
i;
                               11
So far so good; even the output (not shown) makes sense. BUT: as I increase the number of iterations in the for...do loop, the memory allocation goes up fast, and I hit a point at about 40 iterations where the whole process locks up and the program never ends, cannot even be stopped (at least for 100 iterations), forcing me to abort the whole thing. I have evidence that Maple allocates vast amounts of memory which finally chokes the whole thing (on a 16 GB-RAM machine).

Anyone have any idea what I am doing wrong? I realize the above example does not provide benefits; in the real example there will be 6 Creates and the loop will Wait for all of these to finish.

I'd really like to get this to work as each function can take quite some time and I do expect at least some speed-up from parallelizing this (even after overhead).

This is on Maple 2015 on Mac OS X 10.10.5 with 16 GB of RAM. I should mention that I set UseHardwareFlots:=true in my .mapleinit file.

Thanks,

M.D.

I am trying to use Compiler:-Compile with a generated function having a Vector as an argument. My function is (in a simplified form)

Mapt:=proc (pv) options operator, arrow; rtable(1 .. 6, {1 = .998026692438229*pv[1]-.605526643146912*pv[2]+0.154549004943741e-1*pv[6]+0.140818440886566e-5*pv[5], 2 = 0.651134546344795e-2*pv[1]+.998026692438228*pv[2]-0.510903331894809e-1*pv[6]+0.229399145141077e-8*pv[5], 3 = -.500000000000002*pv[3]-5.95856898901206*pv[4], 4 = .125869147673385*pv[3]-.499999999999996*pv[4], 5 = 0.510903331894806e-1*pv[1]-0.154549004943901e-1*pv[2]-40.6778361021594*pv[6]+.999998210424947*pv[5], 6 = .999998210424947*pv[6]-0.229399145141220e-8*pv[1]-0.140818440886565e-5*pv[2]+0.897571581395136e-7*pv[5]}, datatype = anything, subtype = Vector[column], storage = rectangular, order = Fortran_order) end proc;

Since this returns a Vector it cannot be compiled as is. So I split off the first output element (with the idea to later on do this with the others as well):

xpr:=eval(Mapt(<pv[1],pv[2],pv[3],pv[4],pv[5],pv[6]>))[1];
f1:=unapply(xpr,pv);
f1(<0.001,0.001,0,0,0,0>); # test f1: works
          0.000392500049291317

sf1:=Compiler:-Compile(f1); # this works, too

sf1(<0.001,0.001,0,0,0,0>); # but this fails
Error, (in sf1) invalid input: expecting a hardware float[8] rtable, but received 1


The examples in the Helpfile run so I think my installation is ok (my old Maple 15 won't even run the examples, but that is a different story). I have been banging my head against the wall here, trying many different ways, but none of them successfull. Worse, I do not understand the error message at all. Test program attached.

Mac OS X 10.10.5

Thanks for any hint,

M.D.

Compiler.mw

I want to solve the following equation for E[k]:

fr = 1.64*10^6*E[k]^2*exp(-8.5/E[k]);

Maple 17 gives

solve(fr = 1640000.00*E[k]^2*exp(-8.5/E[k]), E[k]);

          4.25000000000000             4.25000000000000     
    ----------------------------, --------------------------
            /  5442.65560181792\          /5442.65560181792\
    LambertW|- ----------------|  LambertW|----------------|
            |        (1/2)     |          |      (1/2)     |
            \      fr          /          \    fr          /

Maple 2015 gives:

solve(fr = 1.64*10^6*E[k]^2*exp(-8.5/E[k]),E[k]);
Error, (in solve) invalid input: `evalf/LambertW` uses a 2nd argument, zz, which is missing

This is Maple 2015.2 on OS X 10.10 Yosemite.

I can copy-paste Maple 17's solution into Maple2015 and it evaluates correctly (for a given value of fr).

Is this a bug or am I missing something? Help on LambertW looks identical for both versions of Maple.

M.D.

I have the following equation:

Diff(W(t), t) = -q*V*(sin(Phi)-sin(Psi[s]))/(2*h*Pi);

I solve it for rhs() = 0:

soln := solve([rhs((2)) = 0, Phi < 2*Pi], [Phi], allsolutions = true,explicit);

This works and I get this result:

Now I want to get the first zeros, which occur for _Z1 and _Z2 equal to 0. So I substitute:

subs(_Z2=0,(3));

and get

In other words, the substitution did not work.

The original problem is embedded in a larger sheet created with Maple 15 and there it does work. It fails on Maple 2015.2. I then pulled out the relevant pieces to make this example demonstrating the problem (see the attached sheet, which has some of my other (unsuccessful) attempts to diagnose what is going on). It seems like the created variables _Z1 and _Z2 are somehow not recognized at all.

The only way I can get the _Z2 terms out is to substitute 2=0. This is really too icky to seriously consider, though.

Anyone has seen this before?

FWIW: Maple 2015.2 on Mac OS X 10.10.5.

Thanks,

Mac Dude

Assumptions_test.mw

I have run into a problem with a file I am preparing for a class. The file is in Document mode with one large section and a number of subsections. Input is 2-d input.

The first subsection behaves normally, input is there, output is there and so on.

The second section does not display the input. The input is still there, somewhere, as the sheet recalculates properly and I can also see there is input when looking at the file with an editor. But no show in Maple.

The third subsection does not show input either.

The fourth subsection is normal again and shows input.

Each of these sections is several screens long. The file actually is an older one where I am adding subsections. The first one (that works normal) is a new one. The original file (before I edited it to add a subsection) works fine still.

So I assume I inadvertently did something that causes this, even though the old subsections are not being edited. I do load Physics[Vectors] but cannot believe that does it. The original file also loads it.

The file was created in Maple 15 and that is where I edited this one. I opened it in Maple 2015 on a different computer, but the behaviour is identical.

Again, the input is there somewhere; the sheet recalculates corrrectly, but I cannot edit the input in the sections that do not show it (I guess that is not a surprise, but it excludes things like a white font color on a white background as there is nothing to select).

Does anyone have a hint how to unhide the input? I tried many things (menu, contextual menu, prefs,...) but no help. It is actually kind-of annoying.

FWIW, this is on Mac OS X, 10.10.5 Yosemite for Maple 2015.1. And 10.5.8 for Maple 15.

Thanks,

M.D.