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I solve a linear system of equations which is rank deficient. Naturally, when Maple solves it symbolically, it chooses some of its variables to use them as a basis to express the solution. 

In a specific problem I'm solving, the basis chosen by Maple is -very- smart, showing a good exploitation of the problem structure. 

I'm curious as to what kind of factorization is used by default, or if there's a lot of by hand "black magic" involved, what are its general characteristics. 

 

Best regards

Claudio

Sorry for the uninformative title. I've never used Maple, but I'm willing to buy a student license and learn it. But before spending too much effort and money I need to know if it suits my needs.

Basically what I need to do is:

1) I have a positive definite symmetric matrix of size nxn, where n can range from 2 to inf. I don't know the elements, except the fact that the diagonal has ones everywhere. All I know is that the elements out of the diagonal are in the range [0,1)

2) I have to compute the lower triangular cholesky decomposition of this matrix, lets call it L.

3) I need to subtract from each element of L the mean of the elements in the respective column. Lets call this matrix L*

4) Then I need to evaluate another nxn matrix computed from the elements of L* following a simple pattern.

5) Finally I need to find the eigenvalues of this last matrix.

What I would ideally want is to get a symbolic representation of the n eigenvalues as symbolic functions of the (unknown) elements of the matrix at point 1.

I can drop the assumption of n being unknown, i.e. fix n=3 and get the 3 functions that, after replacing the right values, give me the eigenvalues, then fix n=4 and get 4 functions, etc.

Is this possible to do in maple?

Thank you

I am able to get unlimeted numbers of equations describing my system. These equations are generally relate quotients of multivariate polynomials. Each additional equation I get is generally less than twice the length of the last, and it is not always the case that an equation is independant of the previous equations. Although I can get unlimited numbers of equations describing the system, it is not overdetermined.

I am interested in solving these equations for their variables. There are about 30 cases I am working on, the smallest number of evariables is six, the largest would be twenty.

I want to be able to solve these equations in the minimal time possible. But I don't understand the function solve well enough to do so.

How do I choose the equations to minimise the time taken for the command solve to proccess them?
How does the command solve work?

particularly:

  1. if I process the command solve([Eq1,Eq2,Eq3...Eqn],variables) would the command solve([Eq[1],Eq[2],Eq[3]...Eq[n],Eq[n+1]],variables) take longer if Eq[n+1] is not indipendant of the previous equations? 
  2. Is there a way of checking whether Eq[n+1] is independant of the previous vequations, fast enough for it to be useful to check the equations before they are processed?
  3. Does the ordering of the equations affect the speed of solve?
  4. Is there a way of pre processing the equations before they are put into solve that will save it time? (for example factorising them, simplifying them etc...)

 

 

I try to find the exact (symbolic) value of

(-2*sqrt(7)-4)*EllipticK((1/8)*sqrt(2)*(-3+sqrt(7)))^2+4*EllipticE(-(1/8)*sqrt(2)*(-3+sqrt(7)))*sqrt(7)*EllipticK((1/8)*sqrt(2)*(-3+sqrt(7)))

I tried 'simplify' with different options and 'convert'. It would be pi=3.141... as numerical approximation suggests.

Many thanks.

when the variable is in limits of integration?

hw2_example.mw

there exist an error : 

Error, (in int) unable to compute a numeric answer for symbolic limits, q = -3.141592654+arccos(11./(1.+.1000000000*t)) .. 3.141592654-1.*arccos(11./(1.+.1000000000*t))

How to make this code work?

Assume the inequality xA,2+xB,2+xC,2 ≤ 110 has to be entered as "symbolic entry only".

How can I check that in Maple T.A.?

It seems that there are type conversions necessary. I attempted to use the MathML package without any luck.

  1. Tried to transform $ANSWER within the answer field using MathML[ExportPresentation]( x[A,2]+x[B,2]+x[C,2] <= 110) and compare it with evalb(($ANSWER)=($RESPONSE)) in the grading code field
  2. Tried to transform $RESPONSE in the grading code: evalb(($ANSWER)=( MathML[ImportContent] ($RESPONSE)))

What’s the format of a symbolic entry? Is it really MathML!?

What is the correct way to do it?

  1. answer: ?
  2. grading code: ?
  3. expression type: Maple syntax?!
  4. Text/Symbolic entry: Symbolic entry only

I want to work (cross products, differentiating and simplificating) of three dimensional vector functions.

But I'd like to work with them as vector, not as components. Is it available in Maple?

Why am I getting different results in these two cases ?

 

How to calculate the integral

(symbolically or/and numerically) with Maple?

 

Hello, i am recently doing a lot of my (really simple) equation manipulations with Maple and would like to include an expectation operator E( ) in my symbolic equations. As maple threads E() as a function, differentiating is not very convenient, as i have to replace all D(E) ... manually. I tried defining some properties of E() via the define() function, but when trying to set the behavior of d E(f(x))/dx I am not sure how to use (diff()=result) in the define() function. Any help or ideas are greatly appreciated!

hi,

how can I convert the decimal representation of the symbolic expressions: I dont want the result in terms of symbols like e^5 or ln(3) 

 

thanks

 

Let us consider the definite integral

J:=int(abs(x-(-x^5+1)^(1/5)), x = 0 .. 1);

Maple fails with it, Mathematica 10.1 finds it in terms of  special functions. Let us look at the integrand:
plot(x-(-x^5+1)^(1/5), x = 0 .. 1);

We see the expression under the modulus changes its sign at the unique point of RealRange(0,1). Therefore

solve(x-(-x^5+1)^(1/5));


Then

J:= int(-x+(-x^5+1)^(1/5), x = 0 .. (1/2)*2^(4/5))+int(x-(-x^5+1)^(1/5), x = (1/2)*2^(4/5) .. 1);

which outputs a complicated expression

(1/8)*2^(4/5)*(4*hypergeom([-1/5, 1/5], [6/5], 1/2)-2^(4/5))+(1/2)*2^(4/5)*((1/2)*2^(1/5)-(1/4)*2^(4/5))-(1/25)*Pi*csc((1/5)*Pi)*(-(25/2)*sin((1/5)*Pi)*GAMMA(4/5)*2^(4/5)*hypergeom([-1/5, 1/5], [6/5], 1/2)/Pi+(5/4)*sec((3/10)*Pi)*cos((1/10)*Pi)*2^(3/5)*Pi^(1/2)*csc((3/10)*Pi)/GAMMA(7/10))/GAMMA(4/5).

At the same time we have

int(abs(x-(-x^5+1)^(1/5)), x = 0 .. 1, numeric);

                          0.5000000000

How to obtain 1/2 symbolically?






can I extract a certain non numeric degree from an expression?

for example, I want to get degree "n-1" from "x^(n-1)+y".

 

any thoughts? 

Hello,

 

I wonder if it is possible to create standalone executables in Maple that would run in a  computer without Maple. Also if it is possible can we do that with Matlab code in it too?  

 

Matlab does not allow to create standalone executable is you use symbolic toolbox and I want to find a solution for that. What I will need to take second derivatives and get the coefficients of polynomials. 

Greetings to all.

I am writing to alert MaplePrimes users to a Maple package that makes an remarkable contribution to combinatorics and really ought to be part of your discrete math / symbolic combinatorics class if you teach one. The combstruct package was developed at INRIA in Paris, France, by the algorithmics research team of P. Flajolet during the mid 1990s. This software package features a parser for grammars involving combinatorial operators such as sequence, set or multiset and it can derive functional equations from the grammar as well as exponential and ordinary generating functions for labeled and unlabeled enumeration. Coefficients of these generating functions can be computed. All of it easy to use and very powerful. If you are doing research on some type of combinatorial structure definitely check with combstruct first.

My purpose in this message is to advise you of the existence of this package and encourage you to use it in your teaching and research. With this in mind I present five applications of the combstruct package. These are very basic efforts that admit improvement that can perhaps serve as an incentive to deploy combstruct nonetheless. Here they are:

I hope you enjoy reading these and perhaps you might want to feature combstruct as well, which presented the first complete implementation in a computer algebra system of the symbolic method, sometimes called the folklore theorem of combinatorial enumeration, when it initially appeared.

Best regards,

Marko Riedel.

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