I am faced by the problem where I used Grid:-Seq()---locally---to do some long time computation and I am faced by the exhaustion of memory problem. I think the problem itself is related to the memory management in maple.

So the problematic function is

# Procedure: ComputeEventsCTypeGrid
#   Compute events such that three quadrics intersects in a point.
#
# Parameters:
#   Q          - a set of quadrics
#
# Output:
#   Indexes of quadrics which intersect in a point.
# TODO:
#  - Memory
#  - Cleanups
ComputeEventsCTypeGrid := proc( Q )
  local s, cType, i, j, k, rootNb, univ, sys;
  s := proc (i, j, k)
    sys := [ Q[i], Q[j], Q[k] ];
    univ := PolynomialIdeals[UnivariatePolynomial]( indets( sys )[1], sys );
    if not type( univ, constant ) then
      rootNb := nops(select(proc(x)op(x)[2]>0;end proc,RootFinding:-Isolate( univ, [ op( indets(univ ) ) ] )) ):
      if rootNb > 0 then
        return [ univ, rootNb, sys ];
      end if:
    end if:
  end proc;
  cType := [Grid:-Seq(seq(seq(s(i,j,k),k=j+1..nops(Q)),j=i+1..nops(Q)),i=1..nops(Q))];
  return cType;
end proc:

A dump from top after calling ComputeEventsCTypeGrid for some data(total amount of memory on this machine is 251G + 48G swap)

VIRT    RES    SHR S  %CPU %MEM     TIME+

33.007g 0.031t   3676 S   0.0 12.5   2606:20
31.137g 0.029t   3436 S   0.0 11.7   2274:34
8645756 4.984g   2840 S   0.0  2.0  32:06.40
28.798g 0.026t   1968 S   0.0 10.7   1821:16
26.650g 0.024t   1968 S   0.0  9.8   1520:54
25.346g 0.023t   1968 S   0.0  9.2   1236:44
23.296g 0.021t   1968 S   0.0  8.4   1004:52
20.498g 0.018t   1968 S   0.0  7.4 790:30.81
16.799g 0.014t   1968 S   0.0  5.9 625:28.12
15.011g 0.013t   1968 S   0.0  5.2 469:36.27
7678444 4.149g   1968 S   0.0  1.6 104:34.22
6734804 623904   1968 S   0.0  0.2  73:13.13
4327420 132516   1968 S   0.0  0.1  24:11.51
3420712 111336   1968 S   0.0  0.0  11:26.16
13.671g 0.011t   1964 S   0.0  4.6 380:15.13
11.771g 9.831g   1964 S   0.0  3.9 274:25.59
9936056 7.769g   1964 S   0.0  3.1 201:13.94
8805512 3.394g   1964 S   0.0  1.3 148:09.53
5077056 1.500g   1964 S   0.0  0.6  42:19.29
2384784  82040   1832 S   0.0  0.0   3:56.57

Size of output data calculated with

> length(sprintf("%m", eval(cType)));

> 326260610

Also, I called gc() at the end of the computations but memory allocated by instances of mserver were not released. Does it mean gc() should be called from each instance separately? My final point is that I have to run some other calculations for different and bigger dataset (It will probably take 2 days to finish -- Q has around 700 polynomials of degree 2) and for this moment I cannot do this because I've gotten an error about not enough amount of memory.

I have 2 questions.

1) The help pages discuss the use of functions described by piecewise when using dsolve. The examples are clear enough but nothing is said about using the numeric option and piecewise. I get an error message for a very simple example: y' +R(t) y^2 = 0. Are I correct in assuming that dsllve numeric cannot deal with piecwise continuous functions?

2) I tried to solve a system of 2 second order constant coefficient linear ODEs using dsolve. After a very long wait (over an hour) I gave up. I tried again using "method=laplace" and got an instant answer. I did not bother to mention it here but it occurred again, this time with a fourth order and second order constant coefficient system. Very strange! I know that the laplace transform is a very useful tool; shouldn't Maple also know that?

Download PDE_equation2.mw

Hi all,

I have the following PDE, is it solveable by Maple or not. Do I need a boundary condition and how many or I can get a general solution? I am new to Maple. Any help will be appreciated.

Thank you.

I have two big equations in terms of 'a & w'. 

While solving two equations, it shows "The solution may be lost".

!!!!!!!!!!!!!!!!!! (This is my problem file)

Kiran_Mukund_(solve).mw

!!!!!!!!!!!!!!!!!!

Please suggest me a solution.

Thanking You

KIRAN MUKUND

I have three separate matrices with 3 function values, and i want to plot them all together. I tried using listplot3d, but it seems to be impossible. How do i do it?

I'm new to Maple, and I come from using Matlab.  Apparently my Matlab way of thinking isn't working on Maple.  I'm trying  to ride a bit of code that simulates flipping a coin 1000 times.  The code counts one partiuclar result (1=heads) at the end prints that result.

Here's the code:

dice:=proc()

count:=0:  

for i from 1 to 10000 do  

roll := rand(1..2):  

roll:=()  

if (roll=1) then count:=count+1 end if  

end do  

print(count)  

 I get errors saying I didn't terminate my loops correctly.  Help, please.

Hi everyone. This problem is driving me nuts. I'm pretty sure it's a glitch but I'm not sure how to solve it. I'm trying to do some data analysis with Maple:

(as a side note, even if I remove the for loop but don't execute the restart command the error remains, however if I get rid of the for loop and execute the restart command it is fine.)

Any help would be greatly appreciated. As it stands this is really driving me insane.

How can I quickly  convert a maple file ful of equations into MathML in Word, nt losing the upper and lower index structure - basically to be able to count each letter in MS Word 2013?

When I tried via Latex or MathML, I have lost the letter structure and got the conversion as an image.

Euler := proc (f::procedure, a, b, alpha, n::integer)
local w, h, i, xN, yN;
w := array(1 .. 2, 1 .. n+1);
h := (b-a)/n;
i := 1;
xN := a;
yN := alpha;
while i <= n+1 do
w[1, i] = xN;
w[2, i] = yN;
print*w[1, i]
yN = yN+h*f(yN, xN);
xN = xN+h;
i = i+1
end do;
print*w
end proc

Hello.

I want to to evalute a picewice variable for a vector of values (like t=<0,0.1,0.2,0.3,...,10>) through a button action's code, but i do not know how can i do that. I have attached a picture of my problem. Could you please help me to solve it?

Thank you.

Hello,

I am new to Maple. I am working on PDE and I wanted to try an easy example to know how to work with Maple. So, I startted with the example from the HELP, but still get error as shown below. Can someone guides me.

Thank you.

How can I make tick marks on the 2-D plot more visible. Attached is a figure created using my maple 2015 student edition

Eight matrices inside the list J:

J := [Matrix([[1, 0], [0, 1]]), Matrix([[0, -I], [-I, 0]]), Matrix([[0, -1], [1, 0]]), Matrix([[-I, 0], [0, I]]), Matrix([[-1, 0], [0, -1]]), Matrix([[0, I], [I, 0]]), Matrix([[0, 1], [-1, 0]]), Matrix([[I, 0], [0, -I]])];

Function member identifies J[2] as a member of J and returns its position in j:

member(J[2], J, 'j'); j;

Matrix multiplication inside a loop does not have a matrix type:

for i to 1 do for j to 2 do a := J[i].J[j]; member(a, J, 'k'); print(i, j, k, a, whattype(a)) end do end do;

Has anyone any ideia of what is going on?

Hi every one, I'm trying to plot the function f which is functions in terms of Bessel functions:Here is the code plz any advise i'll be grateful.

restart:
assume(d,real):assume(t,real):omega:=10^6:Digits:=15:assume(n,real):Delta:=0:
N:=1:N1:=1+2*N;M:=sqrt(N*(N+1));alpha:=M/(2*omega):z(0):=-1:
3
(1/2)
2
I1:=simplify(Sum(BesselJ(n,-I*alpha)*(1/(N1+I*2*omega*n))*(exp((N1+I*2*omega*n)*t)-1),n=-10..10)):

sz:=z(0)*exp(-N1*t)*exp(-alpha*sin(2*omega*t))-exp(-N1*t)*exp(-alpha*sin(2*omega*t))*I1:
I3:=Sum((BesselJ(n,-2*alpha)*(-1)^n+BesselJ(n,-2*I*alpha))*exp(-(N1-I*Delta+2*n*omega)*t),n=-infinity..infinity):
w:=laplace(I3,t,s): w1:=subs(s=I*d,w):
w2:=limit(sz,t=infinity):
Need to plot f
f:=w1*w2:
with(plots):plot(Re(f),d=0..5,tickmarks=[2, 2],thickness=2,linestyle=1,color=black,axes=boxed,titlefont=[SYMBOL,14],font=[1,1,18],tickmarks=[2,3],thickness=2);
Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct