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Ronan

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12 years, 315 days
East Grinstead, United Kingdom
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These are questions asked by Ronan

Eigenvector output flipping ...

Ronan 1311 Maple 2024
sort eigenvalues eigenvector
April 07 2024
2 6

I have a problem with the order  of the Eigenvalues and Vectors flipping. It is a bit random. I only found it trying to understand why a procedure sometimes rotated a conic one way and  then the other. This a really causing a quite a problem, I have only tried this in Maple 2024 so far. I have included screen shots to prove the effect.

> 

restart
> 

 

> 

with(LinearAlgebra):
> 

 

> 

M:=Matrix([[0,1],[1,0]]);
> 

a,b:=Eigenvectors(M)  ;#click here and press enter again possible a 4 times, output can filp
> 

 

Matrix(2, 2, {(1, 1) = 0, (1, 2) = 1, (2, 1) = 1, (2, 2) = 0})

  

Vector[column](%id = 36893491125752073860), Matrix(%id = 36893491125752073980)

 (1)
> 

a

Vector(2, {(1) = 1, (2) = -1})

 (2)
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b

Matrix(2, 2, {(1, 1) = 1, (1, 2) = -1, (2, 1) = 1, (2, 2) = 1})

 (3)
> 

 

 

Download 2024-03-21_Q_Eigenvector_output_flipping.mw

What causes multiple ">" symbols in one ...

Ronan 1311 Maple 2024
worksheet editing
March 31 2024
0 1

I have seen this quite a bit in blocks of code. The `>` symbol seems to appear erratically. I don't know how to specifically reproduce this. Does it mean something? I would post the worksheet but it will not run without the package.

Option to display or not display a defau...

Ronan 1311 Maple 2024
package module initialization
March 27 2024
1 7

I setup my package to display the a message when it is loaded. It is quiet convienent but I don't need it all the time. Obviously I can "#" in the code to hide it premanently. I was wondering if there is away to optionally turn it off/on. Something along the lines.

with(RationalTrigonometry,false) or with(RationalTrigonometry)[false]....

Or put something in the .ini flie to set the default behaviour.

restart:with(RationalTrigonometry):
 "Default global settings:-

     GeomClr = "Blue",

      Prntmsg = true,

       Prjpsn = 3 can be set to 1,

      Normalgpt = 1 or set to 0, 

    Metric is a 3 x3 symmetric matrix defaults to the Identity 

    matrix "

 

2024 possible bug...

Ronan 1311 Maple 2024
open windows10
March 21 2024
0 4

Windows 10 64bit

If I double click on a  file to open it from explorer  i.e. launch Maple, it is 50/50 whether Maple hangs on opening the file and I have to kill it in the Task Manager. This only happens the 1st time I try to open the file. Subsequent clicks on it will open it. If Maple is already open the problem does not happen.  The problem willl also be there after the PC is restarted. Has anyone else noticed this?

How are the two spellings colour and col...

Ronan 1311 Maple 2024
parameters procedure spelling
March 20 2024
1 1

I have used "colour" as my spelling on optional inputs to procedures in my package.  How can I also handle the alternative spelling "color"?  
 

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restart
> 

 

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coltest:=proc(c)
  if c="b" then return 1
   elif c="r" then return 2
   elif c="g" then return 3
  end if;
end proc:
> 

 

> 

foo:=proc(a,{colour:="b"})
local COL;
   COL:=coltest(colour);
if COL=1 then return a
  elif COL=2 then return a^2
  elif COL=3 then return a^3
  else error `wrong colour`;
end if ;
end proc:
> 

 

> 

foo(3,colour="r")

9

 (1)
> 

foo(2,colour="p")

Error, (in foo) wrong colour

  
 

 

Download 2024-03-21_Q_colour_or_color.mw

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