Markiyan Hirnyk

Markiyan Hirnyk

7153 Reputation

25 Badges

11 years, 124 days

MaplePrimes Activity


These are Posts that have been published by Markiyan Hirnyk

Let us consider the help to RectangleWindow SignalProcessing-RectangleWindow.pdf SignalProcessing-RectangleWindow.mw.
Let us execute the example, taking N:=4 (in order to display the outputs).

with(SignalProcessing):
N := 4;
a := GenerateUniform(N, -1, 1);
         Matrix(1, 4, [[.396167882718146, -.826878267806025, -0.908376742154361e-2, .324899681378156]])         
RectangleWindow(a);
         Vector[row](4, [.396167882718146, -.826878267806025, -0.908376742154361e-2, .324899681378156])      
c := Array(1 .. N, 'datatype' = 'float'[8], 'order' = 'C_order'):
RectangleWindow(Array(1 .. N, 'fill' = 1, 'datatype' = 'float'[8], 'order' = 'C_order'), 'container' = c);
              Vector[row](4, [1., 1., 1., 1.])
u := `~`[log](FFT(c)):
plots:-display(Array([plots:-listplot(Re(u)), plots:-listplot(Im(u))]));



We see an uncommented code which (intentionally or unintentionally) produces two empty plots.
The questions arise:

  • What is the aim of the RectangleWindow command which does nothing 
    but the conversion of a Matrix(1,N,...) /Array(1..N,...) to a Vector[row](N,...)? 
  • Could such help be called friendly to Maple users?

There are many questions to Maplesoft and there are no answers from them: strategic silence.
RectangleWindow.mw

 

Let us consider the linear integer programming problem:

A := Matrix([[1, 7, 1, 3], [1, 6, 4, 6], [17, 1, 5, 1], [1, 6, 10, 4]]):
 n := 4; z := add(add(A[i, j]*x[i, j], j = 1 .. n), i = 1 .. n):
restr := {seq(add(x[i, j], i = 1 .. n) = 1, j = 1 .. n), seq(add(x[i, j], j = 1 .. n) = 1, i = 1 .. n)}:
 sol := Optimization[LPSolve](z, restr, assume = binary);

Error, (in Optimization:-LPSolve) no feasible integer point found; 
use feasibilitytolerance option to adjust tolerance

sol1 := Optimization[LPSolve](z, restr, assume = binary, feasibilitytolerance = 100, integertolerance = 1);

Error, (in Optimization:-LPSolve) no feasible integer point found;
 use feasibilitytolerance option to adjust tolerance

That was OK in Maple 16, outputting

.

The bug in one of the principal Maple commands lasts since Maple 2015, where the above code causes "Kernel connection has been lost". The SCRs about it were submitted three times (see http://www.mapleprimes.com/questions/204750-Bug-In-LPSolve-In-Maple-20151).

Let us consider 

restart; 
MultiSeries:-limit(sin(n)/n, n = infinity, complex);
0

The answer is wrong: in view of the Casorati-Weierstrass theorem the limit does not exist. Let us try another limit command of Maple

limit(sin(n)/n, n = infinity, complex);


(lim) (sin(n))/(n)

which fails. Therefore, Maple user does not obtain the correct answer. 

I'd like to pay attention of Maple community to the recent work by Alex Degtyarev in algebraic geometry done with Maple.

Bertini.zip

Let us consider 

with(Statistics);
U := RandomVariable(DiscreteUniform(-10, 10)):
V := RandomVariable(DiscreteUniform(-10, 10)):
Probability(U^2-V^2 <= 1/9, numeric);
  0.

, whereas a positive number greater than 1/21 is expected. 

 

1 2 3 4 5 6 7 Last Page 1 of 16