Ronan

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14 years, 53 days
East Grinstead, United Kingdom

MaplePrimes Activity


These are questions asked by Ronan

I have a proceure that returns 7 values. I cac get it to return ang single specific value ousing e.g [2] to get the second.
Or a range[3..6] for the third to sixth.

Is there a way to get specific seperated values e.g [1] and[[6]. The procedure is burried in a package so it is difficult to post.

I have noticed over a few questions I have asked recently.
I ask a question.                   It goes to top of active converstaions
Some  one answers                                            "

I Reply                                                                *

A bit of time passes  so slides  of the top six/seven that show

Another Reply/Answer from someone                possibly does not show in active conversations.  I catch this by the orange flag or email notification

I reply                                 Does not appear in active conversations..

       This can kill the conversation chain.

I have even tried changing one of me replys to an answer but did not go to top active conversations again.

Has anyone else expperienced this?  

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)

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

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.

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 "


 

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