Hello.

I want to use units in my calculations, but i recieved an error. I have attached my file. Could you please help me to solve it?

Thank you.

Download Prestressed_Concrete.mwPrestressed_Concrete.mw

A calculation I am currently doing has gotten to the stage where the time taken to integrate is just too much.
I have attached a minimal working example Maple script showing an example of the integration which is very messy. When this is run it takes ~ 10 seconds on my machine which is no issue. However the polynomial sum in this example is only a small version, and it can get, much, much larger. To the point it takes over a day to calculate (but it does evaluate).

The reason for this is that the boole integration method does not scale well with more terms in the sum. It beats the other methods for small sums (like in the example) but when the sum gets larger is not that good. The Riemann method appears to be the best for larger sums, but once again is still slow.

Is there any way to speed this up? As the Boole method is fast for this example and gives a good answer, I was thinking to break the much larger sums into smaller seperate sums and then process them all seperately with the Boole method and add up all the results?

Large_sum_integration.mw

Any feedback would be appreciated :)

To check the point on the belonging to the segment I use the algorithm shown in the example. This is an example of intersection of the two segments in 2d. (We not check for parallelism.) We find the point of intersection of the corresponding lines and solve the equation f1 with respect to t and f2 with respect to tt. If 0 <= t <= 1, then the point belongs to the first segment, and if 0 <= tt <= 1 then the point belongs to the second segment.
(Similarly we can check point on the belonging to the segment in 3d.)
In the example point belongs to the second segment, but not the first. These segments do not intersect.
Question: Is there a function in Maple to find the intersection of the segments or to check on the belonging segment point, to make shorter?

segments_intersection.mw 

I want to plot a function given different value combinations of parameters. I used the following code and it doesn't work. Could anybody please help?

I have lots of subsections for organization and have all the outputs at the end...  is there any way to force all/any sections/subsections to remain closed while the whole page is being evaluated? I still want the section to evaluate, but I want it to stay closed.

Hi,

I'm trying to fill an Array but I don't know the correct syntax, and Maple help isn't much use.

How do I form an Array, A, which has 10 rows and 2 columns. Where one column is say the row number squared and the other column is the row number cubed. 

So A would be:

[1 1]
[4 8]
[9 27] .....

Also, I'm using the square and cube numbers as an example. But is there a general format for doing this, whatever the values I want to put in the array are?

Thanks

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.

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

Think I've solved my problems, thanks.

objectiveproc := proc(mmm)
...
return Trace(abs(M));
end proc:
with(Optimization):
i := 0:
t := 1:
Minimize(objectiveproc(x)-abs(Trace(abs(MA))));

Error, (in objectiveproc) invalid subscript selector

Hi, I'm having trouble with print doing strange things:

a:=1235
                1235

b:=751
                751


p:=1601
                1601

print(The solution `to` a^x = b (`mod ` p) is x = 1323)

                              1601 The solution to (1235^x) = 751 mod is x = 1323


Why has the 1601 gone to the beginning, and how do I make it go to the correct place?

Also is it possible to remove the brackets from around 1235^x?

And is it possible to make the brackets (that I have put in) go around the `mod` p?

EDIT:

If I do: print(The solution `to` a^x = b (`mod ` ,p) is x = 1323)

I get:  The solution to (1235^x) = 751 (mod, 1601) is x = 1323

So is there a way to just remove the comma on the output?


Thanks.