Is there something I should be doing whenever I use simplify to avoid things like this, or should I stop using the "is" function all together?

 

Download main.mw

Hello people :) 

As the captian says, im trying to remove an old task i've made.
But i get this:

Error in Get, invalid object [_XML_reply_data_get("reference" =
"_Maplets_reference_12","parameter" =
"value",_XML_content("Task,UserTasks,Nyops",&Entity "#xc3",&Enity
"#xa6","tning"))]

And i have no idea what it is, but it won't erase my task :'D

Thanks a bunch in advance! 

Have a great weekend you all
Best regards Lucas :)

Hi 

I was wondering someone could help me with something.

Basically I've got a function of f(x,z) that I have plotted which comes from an integration that was taken over a large number of small steps. I have been able to plot this function to determine a Potential Field as a function of x and z. (No Problems so far)

However the next step that I want to be able to do is compute a field form this potential. apologies for my lack of knowing how to input into here as I am fairly new to this. To do this I have:

Field = - Nabla * Potential 

Again no problem, I can plot a gradient field from it which is great using the gradplot command. I beleive this comes as a result of the following:

gradplot = [diff(f,x), diff(f,z)]

HOWEVER I want to be able to plot a Field Strength plot (In essence a Gradient Field Strength) where it takes the magnitude of the vectors at each point. Firstly am I correct in saying that this should be:

Magnitude Field = |F| = sqrt( Fx^2+Fz^2)      where Fx is diff(f,x) and Fz is diff(f,z)

However when I try to compute this, it takes an age to evaluate and doesn't seem to make much progress. I think this may come as a result of computing square roots of large numbers/large decimal places? I was wondering whether there is any command that anyones knows of that would calculate Gradient Field Strength/Magnitude that may solve this issue? Or even who to just compute this Square root?

A few seconds after calling up Help starts zucking araound and the whole computer then freezes. Ctrl-Alt-Delete doesn't work, hard reset required. Very funny. Am I alone?

Hi good afternoon , im looking for maple code of HPM to solve time dependent diffusion reaction , can anybody help me . I didnt get how to solve it by maple . 

Hello

I know that anames( 'user' ) recovers the contents of the workspace but I wonder whether it would be possible to recover only the contents of each m-file read within a worksheet.  

Many thanks

Ed

My maplet

mpt := Maplet(Window("Точка выше или ниже прямой",
[[Plotter[f]()], ["1st vector"],
[TextField[v1](), TextField[v2](), TextField[v5]()],
["2nd vector"],
[TextField[v3](), TextField[v4](), TextField[v6]()], ["Скаляр"],
[TextField[scalar]()], [Button("Add", Evaluate(f = 'work(1)'))],
[[ToggleButton['d2']("2D", 'value' = true, 'group' = 'BG1')],
[ToggleButton['d3']("3D", 'value' = false, 'group' = 'BG1')]]]),
ButtonGroup['BG1']())

Now I choose via toogle button what to plot 2D or 3D addition but I need to plot it in two different plotter, is there a way to do it?

Procedure 

with(Maplets);
with(Elements);
with(Tools);
[AddAttribute, AddContent, Get, ListBoxSplit, Parse, Print, Set, 

  SetTimeout, StartEngine, StopEngine]
with(plots);
with(LinearAlgebra);
with(Student[LinearAlgebra]);

with(Maplets[Elements]);

work:=proc(g)

     local x1, y1, x2, y2, scalar;z1, z2,d2,d3,u,v,U,V,r1,r2,r3,R1,R2,R3,V1:
 x1 := Get(v1::algebraic);
 y1 := Get(v2::algebraic);  

z1 := Get(v5::algebraic);  

x2 := Get(v3::algebraic);  

y2 := Get(v4::algebraic);  

z2 := Get(v6::algebraic);  

scalar := Get(scalar::algebraic);

 d2:= Get(d2);  

d3:= Get(d3);    

 if d2 = true then  u, v:=<x1, y1>, <x2, y2>;  

elif d3 = true then   u, v:=<x1, y1,z1>, <x2, y2,z2>;  

end if;  U:=arrow(u, color=red):  

V:=arrow(u, v, color=black):    

   r1:=u+v: r2:=u-v: r3:=ScalarMultiply(u,scalar):r4:=ScalarMultiply(v,scalar):  

R1:=arrow(r1, color=red):

 R2:=arrow(v, r2, color=black):  

R3:=arrow(r3, color=black):

 R4:=arrow(r4, color=black):  

V1:=arrow(v, color=blue):    

if g = 1 then return VectorSumPlot(u,v, show=1, caption="Треугольник", vectorcolors=[red,blue]);    

end if;  

end proc:

Repeat once again what do I need: I want to plot addition of vectors in 2D and 3D in 2 different plotters at once

how to convert a function to transition matrix?

how to convert a differential system to transition matrix?

Does global optimization toolbox has randomization option it gives same value every time

In addition to defining a function in a standard way, a fast and convenient way to turn a formula (an expression) into a function is to use unapply command (check Maple help center for this command). The following items are about defining functions. 

1. Define a function midpoint, which returns the average of two arguments given on input. For example, midpoint(2,3) returns 2.5, midpoint(a,b) returns 𝑎+𝑏2. 
2. b) For two positive natural numbers 𝑎 and 𝑏 we can define the least common multiple lcm(𝑎,𝑏) via their greatest common divisor gcd (𝑎,𝑏), i.e.: lcm(𝑎,𝑏) = 𝑎𝑏gcd (𝑎,𝑏). When 𝑎 and/or 𝑏 are zero, lcm(𝑎; 𝑏)=0. Use the arrow operator and piecewise to define the function my_lcm which returns the least common multiple of two natural numbers. 
3. c) The quadratic formula allows to write the roots of 𝑝 = 𝑎𝑥2+𝑏𝑥+𝑐 explicitly in terms of 𝑎,𝑏, and 𝑐. 

 Define a piecewise function of 𝑥 so that the value of the function is 0, if 𝑥<−(𝑟1+ 𝑟2+𝑟3) or 𝑥>𝑟1+ 𝑟2+𝑟3, and it is equal to the area of confined region if −(𝑟1+ 𝑟2+𝑟3)<𝑥<𝑟1+ 𝑟2+𝑟3. 

a) Given real values 𝑟1,𝑟2,𝑟3>0, consider the curve of the positive part of the circle with radius 𝑟1+ 𝑟2+𝑟3 and center at the origin and three semi-circles below with radii 𝑟1,𝑟2,𝑟3 so that they are arranged from left to right like the following graph. Define proper functions and plot this graph in Maple for 𝑟1=10,𝑟2=2,𝑟3=8. 

Hey everyone,

Got another Symbolic question here that I have no idea how to begin. Please help again.

Question: 

Note that if i is an integer then convert(i,base, 2) will convert i to a binary list (the binary representation of i in reverse order). Then you may use list_to_set to convert  this list to a set. Note that if i runs from 0 to 2^n-1 then list_to_set(convert(i,base,2) )  will run through all subsets of {1, 2, . . ., n}. 

(a) Use this idea to make your own procedure PowerSet which will given n,  produce the powerset of {1, 2, . . . , n}. Show by several examples that your procedure works. For your examples you should get nops(PowerSet(n)) = 2^(n). Check that this is the case.
 
(b) Use this idea to make a procedure RandSet which given n produces a random subset of {1, 2, . . . , n}. [Use rand to produce a random integer in the range 0..2^n-1 and then convert it to a subset of {1, 2, . . . , n}.]  Do NOT use PowerSet or powerset. Show by examples that it works for small n such as 5, 10, and 20 as well as for large n such as 100. It will even work for n = 1000, but the output will be rather large. On average a random subset of {1,2,...,n} will contain n/2 elements.

Again, please help me with this and thank you in advance. Your assistance is appreciated.

Hi all,

First-time poster here. Got a question for Symbolic Computations and don't know how to do it. Please help me out.

Here is the question: 

There is a one-to-one correspondence between subsets of {1, 2, . . . , n} and binary lists of length n, that is, lists L = [x1, x2 , . . . , xn] where x1, x2, . . . , xn are elements of the set {0,1}.  The correspondence is given by associating to the set S the list L where xi = 1 if i is in S and 0 if not. For example, the set {1,3,5} corresponds to the list [1,0,1,0,1,0,0] if n = 7.

(a) Write a procedure list_to_set whose input is a binary list and whose output is the corresponding set. E. g., list_to_set([1,0,1,0,1]) will return the set {1,3,5}. Note that nops(L) is the length of a list.

(b) Write a procedure set_to_list whose input is a pair S,n where S is a subset of {1, 2, . . . , n} and n is a positive integer and whose output is the binary list of length n corresponding to the set S. E. g., if n = 5 then set_to_list({1,3,5},5) will return [1,0,1,0,1].

(c) Show by a few tests that each procedure works. Then apply set_to_list to each set in the powerset of {1, 2, 3, 4} to form all binary lists of length 4. Make a program to print out a table of the following form. (But the order need not be the same as that started below.)

   [0,0,0,0] <-->  {  }
   [1,0,0 0] <--> { 1 }
   [0,1,0,0] <--> { 2 } 
    ........
    etc

Some extra commas in the output is okay. You may obtain the power set of the set {1,2,...,n} by the command powerset(n); but you must first load the package combinat.

Please let me know if there are any questions. Thank you in advance.