mmcdara

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6 years, 67 days

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These are questions asked by mmcdara

Hi everybody,

I use the Grid package to do intensive computations.

For some reason I'm ignorant about, the test case described in the Grid[Server][StartServer] 

 help page doesn't work with Maple 2015 (neither on Mac OS X, neither on Windows 7 ; here is the mw file run on MAC Os X)

Could someone explain me why (probably something I did not read with enough attention ... some license maybe) ?
Thanks in advance

GridServer.mw

Hi,

I am a little bit surprised by the result of the operation evalf[8](f(y)) in the piece of code that follows.
I was expected the answer to be 2.4494897, not 2.4494898.

Happily the sequence
res := f(y) ; evalf[8](res)
returns the expected result 2.4494897

I suspect the difference comes from some precedence of the operators (f and evalf) but I can't figure out what really happens

Could you enlight me please ?

Thanks in advance

 

restart:

interface(version);

`Standard Worksheet Interface, Maple 2015.2, Mac OS X, December 21 2015 Build ID 1097895`

(1)

Digits;

10

(2)

f := x -> sqrt(2.0)*x;

proc (x) options operator, arrow; sqrt(2.0)*x end proc

(3)

y := sqrt(3.0):

f(y);

2.449489743

(4)

evalf[9](f(y));  # right

2.44948974

(5)

evalf[8](f(y));  # ????

2.4494898

(6)

res := f(y);
evalf[8](res);  # right

2.449489743

 

2.4494897

(7)

 

 

 

Hello everybody, 

I use Maple to obtain the solution of a reccurrence equation :
r := rsolve({u(n)=n*(u(n-1)+1), u(0)=0}, u)

Now I want to define a function s(n) wich returns the integer value of the nth term u(n).
In the attached file three different attempts to compute the numerical value of s(2) (you can replace "2" by any other positive integer) are given.

  • S := unapply(r, n);
     
  • S := unapply(convert(r, sum), n);
     
  • S := unapply(simplify(convert(r, sum)), n);


But none of them returns an integer and I'm always forced to apply some operation to "transform" the output into the desired integer.
Could you please help me to understand why it is so ?

Thanks in advance

2018.mw

 

Hi everibody 

I work with Maple 2015 under OS-X El Capitan.

Using more than one matrix vector product (either M.V  or MatrixVectorMultiply(M,V)  ; M is a n by p matrix and V a column vector of size p) within the same block of commands generates an error.

Do other people have the same problem ?
Thanks for your feedback.

SomethingGoesWrong.mw


PS : I know I can do this   X . <<1, 1, -1> | <-1, 2, 0>> but this doesn't explain the error I get

 

Hi everybody,

I want to solve numerically an ode and I get this error (undocumented on the maplesoft web site https://www.maplesoft.com/support/help/errors/....)

Error, (in sol) maximum number of event iterations reached (100) at t=2.6610663

I understand where this error can come from but the help pages don't say anything to fix this.
There is some stuff about round-off that could help but I don't understand how to use it.

I would be grateful if you provide me some help.
Thanks in advance


Download ErrorWithDsolve.mw

 

 

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