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Hi,

I have coded up a vector that is of my interest. The code runs witout any problem and gives me exactly what I want.

newtest.mw

All I want to know, is that if there are more efficient way to do so?

Any tricks, or better use of a particular function that I wasn't aware?

The only tiny bit of unsatisfactory is that, the (1-w) term is at the first term of the addition, is that possible to move it to the last term? Which is more conventional to read.

 

Thanks,

 

casper

Hi guys

 

I have an if statement inside a function. This function then get's called in a sum. However, the result is not correct as the if statement checks wether the argument equals 0, but since the sum passes only the summation index name, it doesn't work as intended.

How can I tell Maple, that it has to evaluate the index before passing it on? MWE appended.

 

Cheers

NOh

Comm := proc (n) options operator, arrow; `if`(n = 0, 1, 0) end proc;

proc (n) options operator, arrow; `if`(n = 0, 1, 0) end proc

(1)

Comm(0);

1

(2)

sum(Comm(j), j = 0 .. 0);

0

(3)

``

 

Download MWE.mwMWE.mw

In Maple, I want to define a set of functions by means of two for loops:

    printlevel:=2;

    # Node coordinates.
    N_x:=5;
    N_y:=4;
    N_elx:=N_x-1;
    N_ely:=N_y-1;
    h_x:=(x_e-x_s)/N_elx;
    h_y:=(y_e-y_s)/N_ely;
    x_n:=[seq(x_s+j*h_x,j=0..N_elx)];
    y_n:=[seq(y_s+j*h_y,j=0..N_ely)];

    # Partition of unity.
    for j from 2 by 1 to N_x-1 do
        for k from 2 by 1 to N_y-1 do
            phi[j,k]:=(x,y)->(x-x_n[j-1])*(x-x_n[j+1])*(y-y_n[k-1])*(y-y_n[k+1])/((x_n[j]-x_n[j-1])*(x_n[j]-x_n[j+1])*(y_n[k]-y_n[k-1])*(y_n[k]-y_n[k+1]));
        od;
    od;

However, this gives output in which the `[j,k]` vary but the `x_n[j-1]`, `x_n[j+1]`, `y_n[j-1]` and `y_n[j+1]` are not evaluated. But if I for instance input `x_n[3]` I correctly get 1/2 as answer.

How do I solve this?

I got a problem in using dsolve.
In my real question, some functions are quite complicated.
so here is a simple example.
F1:=x(t)^2;F2:=piecewise(t>=0,y(t)^3,t>=0.1,exp(y(t)));
eq1:=diff(x(t),t$2)=F1;eq2:=diff(y(t),t$2)=subs(x=y,F1)-F2;
ic1:=x(0)=1.2,D(x)(0)=0;ic2:=y(0)=MM(tf),D(y)(0)=NN(tf);
#tf is the point where x(tf)=30.
dsolve({eq1,eq2,ic1,ic2,x(tf)=30},numeric);

above command can't give an answer.

how to use dsolve solve this problem?

any ideas is appreciated.

Hi all

Can anybody suggest an algorithm allowing to detect, that two matrices of the same size can be obtained each from other by permutations of rows and columns? Maybe, such an algorithm there exists in LinearAlgebra package?

Hello Dears

I have this equation

                                          (Napla)^4 * F(x,y) + k^2 *  (Napla)^2 * F(x,y)= 0,      (1)

which may be written as a non-homgeneous Helmholtz equation as

                                          (Napla)^2 * F(x,y) + k^2 * F(x,y)= g(x,y),                (2)

where the function g(x,y) is a harmonic function and (Napla)^2 is the laplace's operator in two dimension.

Can Maple solve equation (1), it will be better. If not may be solve equation (2).

 

I have an integral that maple can not solve but I can solve it by hand. How can I add this to maple integration database?

f:=int(r^2*BesselJ(0,a*r)*BesselI(1,b*r),r)

Please see the file below.

Integral.mw

 

Many many thanks! :)

Hi

How can I substitute a function in a matrix? This is what I tried but it's not working at all:

lign1:=x-y+2*z=1:
lign2:=(-2)*x+y+z=0:
lign3:=(-4)*x+y+7*z=2:
lign4:=3*x-2*y+z=1:
T := GenerateMatrix([lign1, lign2, lign3, lign4],[x, y, z], augmented);

Then I'd like to substitute another function with lign1:

lign5:=x+y+z=6:
T2:=subs(lign1=lign5, T);

But T2 = T and that wasn't really the point.

 

Sorry if the answer is obvious no amount of searching has helped me so far. I hope this question isn't too ridiculous.

Thanks

kappa := Vector(7, [1,w[1]*(1-phi+phi*(1-1/(1+exp(-mu[p]-tau[p3]))))+(1-w[1])*
(1-phi+phi*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2])))),w[1]*phi/(1+exp(-mu[p]-tau[
p3]))+(1-w[1])*phi/(1+exp(-mu[p]-tau[p3]-eta[p2])),w[1]*(1-phi+phi*(1-1/(1+exp
(-mu[p])))*(1-phi)+phi^2*(1-1/(1+exp(-mu[p])))*(1-1/(1+exp(-mu[p]-tau[p3]))))+
(1-w[1])*(1-phi+phi*(1-1/(1+exp(-mu[p]-eta[p2])))*(1-phi)+phi^2*(1-1/(1+exp(-
mu[p]-eta[p2])))*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2])))),w[1]*phi^2*(1-1/(1+exp
(-mu[p])))/(1+exp(-mu[p]-tau[p3]))+(1-w[1])*phi^2*(1-1/(1+exp(-mu[p]-eta[p2]))
)/(1+exp(-mu[p]-tau[p3]-eta[p2])),w[1]*(phi/(1+exp(-mu[p]))*(1-phi)+phi^2/(1+
exp(-mu[p]))*(1-1/(1+exp(-mu[p]-tau[p3]))))+(1-w[1])*(phi/(1+exp(-mu[p]-eta[p2
]))*(1-phi)+phi^2/(1+exp(-mu[p]-eta[p2]))*(1-1/(1+exp(-mu[p]-tau[p3]-eta[p2]))
)),w[1]*phi^2/(1+exp(-mu[p]))/(1+exp(-mu[p]-tau[p3]))+(1-w[1])*phi^2/(1+exp(-
mu[p]-eta[p2]))/(1+exp(-mu[p]-tau[p3]-eta[p2]))]);

Download kappa.txt

Here is the expression, I am trying to simplify, given a set of rules. NEW_Cole.mw

I have tried different substitutions, using simplify with side rules, applyrule, eval, subs, algsubs.

But none seem to be working as the way I want them to be.

 

Is there a better way?

 

Thanks!

I am trying the following:

restart; 
with(Physics);
with(Library);
Setup(mathematicalnotation = true);
Setup(op = A);
assume(n::integer);

type(A^n, Physics:-`^`(PhysicsType:-ExtendedQuantumOperator, integer));
type(A^n, PhysicsType:-ExtendedQuantumOperator^integer);

the result is

false
false

However, I expected to get true in both cases. How to construct correct type for A^n?
Thank you.

1) Consider the followin Integral:

int(cosh(a*x)*cos(b*x),x)

How can I tell maple to give the results in terms of hyperbolic and harmonic funtions?
The maple returns the answer in term of exponentials with imaginary powers.
Also, I could not use the "simplify" command to turn the answer returned by maple into an answer in terms of what I want! Please see the code below.


2) Is there a way that I can update the maple integration database manaully?

 

Example.mw

Hi,

I am new to the Maple Forum and have the following question.I am calculating some Gaussian error propagations and other equations and did this in this way:

[eval(diff(x(y,z),y),[y=...,z=...])2*(dy)2+eval(diff(x(y,z),z),[y=...,z=...])2*(dz)2]1/2

Now I am having several dozens of different y and z for which I have to calculate the above equation. How can I define these variables y and z only once at the beginning before all equations and press the button !!! that everything afterwards is just calculated with the defined variables? This way I would only have to change the variables once instead of several times in each term and for each equation.

Thank you very much. I appreciate your help!

L

Is it possible to evaluate a function at multiple points described by an array or something of that sort and have Maple return the evaluations as an array. I need approximations of a function at various values of its argument so it would be nice to do it with a single command.

Thanks

How do I make "simplify" function to recognize complex exponentials. Maple created some exponentiol functions with a square root of negative expression in the denominator of the exponent. It refuses to simplify it. If I manually edit it, by taking negative sign under the root and adding immaginary number, the simplification works. How do I simplify it without manual edit?

The Eq 33 is manually edited line. Simplify function correctly uses cos function.

The Eq 34 is original expression. I tried to tell maple to assume real numbers hoping that it will wotk, but it did not.

I have question about how to write the expression to get the order in the sequence?

For exmple, if I have this sequence,

E:=[0,2,7,15,26,40]

I want to write a procedure that tells me the location of any input,x in the sequence E.

For example, if I choose x:=3, then the number 3 is actually between 2 and 7, so it will give me the answer C(x)=3 (because 7 is the third elemet).

I try to write the procedure but there always wrong! I do not know what expression should I write!

C:=proc(x)
local
for i from 1 to nops(E) do
if x<=E[i] then
c:=E[i]
fi;od;
end;

Please help! 

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