Hi, all

I use INT to calculate multiple integration as below. It runs more than 20 hours without results. I wander is there any problem in my codes.

restart;
A := sin(k*Pi*(x-h*cos(theta))/a)*sin(l*Pi*(y-h*sin(theta))/b)*sin(k[0]*h)*sin(k*Pi*x/a)*sin(l*Pi*y/b);

W := evalf[5](int(int(int(int(A, h = 0 .. (x-a)/cos(theta)), theta = Pi+arctan((b-y)/(a-x)) .. 3*Pi*(1/2)), x = 0 .. a), y = 0 .. b, numeric))

Thanks

Why the disparity in the solution of P1 and P2? P1 uses finite difference while P2 uses midrich.

See them here P1.mw     and   P2.mw

Hi,

  Suppose I would like to use writedata for a series of files, e.g. test1.txt, test2.txt, test3.txt.  

I tried

***

a_min:=1;a_max:=3;
b_min:=1;b_max:=3;
A:=array(a_min..a_max,b_min..b_max);

for i from a_min to a_max do
  for j from b_min to b_max do 
     A[i,j]:=i*j;
  end do;
end do;

for i from 1 to 3 do
  file_name:=`test||i`;
  writedata[APPEND](file_name,A);
end do;

****

Seems "||" inside `` does not work, is there any robust solution for this issue? 

Thank you very much

I am trying to define a new typt and I am beating my head against the wall...

What I have working:

TypeTools:-AddType(Element,'record(l,R)');
 
This defines a type which I can then use in type(xpr,Element) to be false or true depending on whether xpr is a record containing (at least) entries l and R or not.

Now I want to define a type ExpandedLine that is a Vector of Element (Element in the sense above). In fact, in the context of my application I am willing to settle for ExpandedLine being a Vector of record.

Tried various approaches (and making sure Vector is in uneval quotes in the AddType statement) like:

TypeTools:-AddType(ExpandedLine,'Vector'(record));

and variations but no luck.

Any help is appreciated.

Mac Dude

I want to put the solution obtained from ShowSolution() command of Student[Calculus1] into my LaTeX file. How I can achieve that?

I succeeded in getting latex of ExpandSteps because it was a module, but ShowSolution() is not a module.

Hello everyone,

I have nonlinear partial differential equations (see the attached file) need to be solved:

https://drive.google.com/file/d/0B14...ew?usp=sharing

With initial condition: h(x, y) = K1 (constant), dh/dx = K2 (constant); dh/dy = K3 (constant); And h(x,y) is function of (x,y) other factors are constant. Could anyone tell me how to solve these equations by using numerical method? Do you know any library in c/ c++ language that can solve these equations??

I have tried with Maple 17 and the response is: "Error, (in pdsolve/info) first argument is not a differential equation". Whole of my input:

with(PDEtools); declare(U1(x, y), U2(x, y), U3(x, y));

PDEs = [diff(U1(x, y), y) = U2(x, y),

diff(U1(x, y), x) = U3(x, y),

(diff(U2(x, y), y))*((L-U1(x, y))^2+(D2+tan(alpha)*(L+U1(x, y)))^2)+.5*U2(x, y)*(2*tan(alpha)*U1(x, y)-D2) = 0,

(diff(U3(x, y), x))*((L-U1(x, y))^2+D1^2*cos(alpha+2*U2(x, y))^2)+.5*U3(x, y)*D1*cos(alpha+2*U2(x, y))+.5*D1*sin(alpha+2*U2(x, y))*(L-U1(x, y)) = 0];

[ d d / d
PDEs = [--- U1(x, y) = U2(x, y), --- U1(x, y) = U3(x, y), |--- U2(
[ dy dx \ dy

\ / 2 2\
x, y)| \(L - U1(x, y)) + (D2 + tan(alpha) (L + U1(x, y))) /
/

/ d
+ 0.5 U2(x, y) (2 tan(alpha) U1(x, y) - D2) = 0, |--- U3(x, y)
\ dx

\ / 2 2 2\
| \(L - U1(x, y)) + D1 cos(alpha + 2 U2(x, y)) /
/

+ 0.5 U3(x, y) D1 cos(alpha + 2 U2(x, y))

]
+ 0.5 D1 sin(alpha + 2 U2(x, y)) (L - U1(x, y)) = 0]
]

pdsolve(PDEs);
Error, (in pdsolve/info) first argument is not a differential equation

I will be very appreciated with your help!!!

I need to convert a base 10 int(defined as num) to its base 3 format using a while loop. I would like to store the remainder of the num%3 to a list/sequence/array in maple. Now, if I were to use a sequence, I would need a pre-defined range. How do I solve this issue?

I've got a piece-wise function(for which I've made the procedure) f defined over x<=-1, -1<x<1 and x>=1 which I am trying to plot over the range of (-2,2). I've tried using plot(f,-2..2) but it doesn't show any curve. Should I add a few more parameters to plot()?

I've got the following lists :

list1:=[1, 5, 14, 30, 55, 91, 140, 204, 285, 385, 506, 650, 819, 1015,

1240, 1496, 1785, 2109, 2470, 2870]
list2:=[1, 5, 14, 30, 55, 91, 140, 204, 285, 385, 506, 650, 819, 1015,

1240, 1496, 1785, 2109, 2470, 2870]

each generated by a procedure I defined. I need to verify that they are equal, which is the case. However, when I tried to use the evalb function as well as a flag that I was updating during a loop, in both cases, I got 'false' as  the answer along with the error message: 

"error, final value in a for loop must be numeric or a character"

What I am doing wrong?

I am required to generate a list containing the square of numbers 1 through k where k is an arbitrary int,defined from 1 to n. To do this, I've currently got the following commands:

local k, mylist:=[];

for k from 1 to n do

mylist[k]=sumsquare(k);

end do;

where sumsquare() is a procedure I defined to compute the sum of the squares of 1 through a number passed as an argument

At present this gives me an out of bounds error. 

How can I initialize mylist to be of size n, like in other languages such as C++?

Hi,

im trying to calculate the divergence of a 3x3 tensor. The tensor is created by the following code:

with(VectorCalculus);
with(LinearAlgebra);
SetCoordinates(cartesian[x, y, z]);
alias(u = u(t, x, y, z), v = v(t, x, y, z), w = w(t, x, y, z)); alias(eta = eta(t, x, y, z));
U := VectorField(`<,>`(u, v, w));
M := OuterProductMatrix(U, U);

The last command gives a 3x3 tensor:

Now I want to calculate the divergence of this tensor. But the function "Divergence" (VectorCalculus-package) is only able to handle vectors. A workaround would be the extract the data row by row -> convert it to a vector -> calculate the divergence.

Is there a more elegant possibility to do this?

Thanks in advance.

Hi,

for my simulation I have to calculate several gradients and jacobian matrices. The equations are quite complex and with my current setup hard to read.

Here is some exampel code:

restart;
with(VectorCalculus);
SetCoordinates(cartesian[x, y, z]);
alias(u = u(t, x, y, z), v = v(t, x, y, z), w = w(t, x, y, z)); alias(eta = eta(t, x, y, z));
U := VectorField(`<,>`(u, v, w));
Divergence(U);
Jacobian(U);
Diff(U, t);

The Divergence operator gives me a very compact result:

But Jaobian and Diff look like:

To achive a better readability I want to do two things (if possible):

1) hide the independet variables (t,x,y,z) in the result of Jacobian, Diff

2) display the result of Diff in a row vector (3x1) instead

Is this possible?

Thanks in advance for your help

I am looking to return all the substrings of a string that match a particular pattern (regexp). This is a very common text processing operation.

StringTools[RegMatch] returns boolean about whether the given pattern exists somewhere in the string. That's a start, but it is not efficient to hunt around for where the match is in order to extract the characters.

StringTools[Search] and [SearchAll] can return position information, but they work on exact matches of the pattern space, not on regular expressions. I could pre-generate all the possible matching sequences of up to some length and search for those exactly, but that is inconvenient at best and pretty much useless if there is a .* or .+ in the regular expression (as the space of potential matches grows exponentially.)

StringTools[RegSub] can be used to find one match by using something like ".*(REALPATTERN).*" = "\1" but since this does not extract any position information, one would at the very least then have to StringTools[Search] of the exact match to determine the position, then take a substring of the original string, and continue searching. And if you are going to do that, you might as well just use StringTools[RegMatch] with an optional third argument of a symbol to return the matched characters, instead of fooliing around with deleting everything else using RegSub.

Have I overlooked a possibility?

Example of use:

I would like to search "variable %1 needs to be of the form %3+2.9 in order to use routine %2 to find the fizturl", extracting the "%1", "%3", "%2". This would be regular expression "%[0-9]+". Notice that there might be other digits in the string that I do not want to extract, so I cannot just search for digits. I also cannot just remove all characters "[^0-9%]" as that would leave digits and would, for example, merge together the %3+2.9 into %329 leaving post-processing to extract the true pattern matches.

For what I am doing at the moment, I do not need to know the positions those occured at, just the matches.

I want to solve a Laplace integral transform step-by-step its as follows:

f(t):=e^at

IntTutor(Int(e^-st f(t),t=0..infinity)

but it says that the expression can't be integrated, and secondly it does not work with 'infinity'. How I can solve this for step-by-step solution?

Thanxs

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