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Petra Heijnen

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18 years, 170 days
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These are questions asked by Petra Heijnen

Problem with integer optimization...

Petra Heijnen 125 Maple
optimization integer kernel
December 08 2015
0 5

When I use the option assume = nonnegint or integervariables = {...} in Optimization[Minimize], or Optimization[LPSolve] I've got the message "kernel connection lost'. 

 

Thie even happens when I use the simple example from the Maple help:

with(Optimization):
LPSolve(2*x+5*y,{3*x-y=1,x-y<=5},assume={nonnegative,integer});

 

It says; mserver.exe has stopped working. 

What's wrong? 

Refresh the cells of a data table compon...

Petra Heijnen 125
June 16 2015
1 3

I've used a data table component connected to an existing matrix that is updated running a loop.

However, the data table component is only refreshed after the loop, not within.

In the Data Table Properties, Enabled is on. 

What else can I do to update the table while running the loop?

I tried to use 

DocumentTools:-SetProperty("PerformanceTable", 'value', PM, 'refresh'=true);

but it doesn't seem to know 'value' as a property.

PM is the matrix it is connected to.

Is it possible to overwrite output?...

Petra Heijnen 125
loop plotting
June 12 2015
1 3

I would like to overwrite a plot that's updated within a loop over time. 

I used animate already, but the problem is that it's  only updated at specific points in time (not regularly distributed) and with animate I can only use frames that are equally divided over the wholre range. To update each time step costs unneeded memory and time. 

I hope that there exists a better solution.

thanks for your help.

What's wrong with TravelingSalesman - Gr...

Petra Heijnen 125
error graphtheory
March 18 2014
3 0

When I check the length of the optimal tour found by TravelingSalesman (GraphTheory package), it's different from the given result. What goes wrong?

See attached file.

``

> 

restart: with(GraphTheory):
> 

G := GRAPHLN(undirected,weighted,[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,

> 

14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25],Array(1..25, [{17, 19},{10, 22
> 

},{10, 14, 23},{6, 12, 14},{6, 7, 19},{4, 5},{5, 13, 15, 16},{12, 13, 14, 15},
> 

{20, 25},{2, 3},{22, 25},{4, 8, 13},{7, 8, 12},{3, 4, 8},{7, 8, 21, 23},{7, 17
> 

, 18},{1, 16, 18, 19},{16, 17, 25},{1, 5, 17},{9, 21, 22},{15, 20, 24},{2, 11,
> 

20, 24},{3, 15, 24},{21, 22, 23},{9, 11, 18}]),`GRAPHLN/table/2`,Matrix(25, 25
> 

, {(12, 13) = 137, (14, 4) = 920, (3, 14) = 902, (5, 6) = 561, (17, 18) = 443,
> 

(22, 11) = 670, (16, 17) = 573, (19, 17) = 330, (18, 17) = 280, (10, 2) = 1630
> 

, (16, 18) = 727, (23, 15) = 760, (17, 1) = 900, (4, 6) = 1216, (16, 7) = 600,
> 

(14, 8) = 260, (12, 4) = 580, (1, 19) = 665, (4, 12) = 733, (19, 5) = 750, (8,
> 

14) = 368, (11, 25) = 1366, (24, 22) = 300, (17, 19) = 495, (21, 15) = 930, (6
> 

, 4) = 1110, (11, 22) = 1049, (12, 8) = 100, (15, 21) = 995, (17, 16) = 520, (
> 

1, 17) = 866, (15, 23) = 833, (5, 19) = 930, (9, 20) = 184, (19, 1) = 630, (7,
> 

15) = 598, (13, 8) = 110, (24, 21) = 250, (3, 10) = 471, (24, 23) = 550, (2,

> 

10) = 1682, (13, 12) = 80, (8, 12) = 202, (21, 24) = 287, (23, 3) = 590, (15,
> 

8) = 410, (14, 3) = 800, (23, 24) = 688, (7, 13) = 526, (8, 15) = 477, (20, 21
> 

) = 245, (2, 22) = 547, (15, 7) = 990, (22, 20) = 420, (10, 3) = 300, (4, 14)
> 

= 933, (5, 7) = 690, (18, 25) = 328, (25, 18) = 270, (21, 20) = 130, (25, 9) =
> 

240, (7, 16) = 406, (20, 9) = 140, (6, 5) = 380, (8, 13) = 236, (20, 22) = 452
> 

, (22, 2) = 500, (9, 25) = 227, (13, 7) = 640, (7, 5) = 670, (25, 11) = 1640,
> 

(3, 23) = 518, (22, 24) = 495, (18, 16) = 700}, storage = sparse));

GRAPHLN(undirected, weighted, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25], Array(%id = 4487072130), `GRAPHLN/table/2`, Matrix(%id = 4488755818))

 (1)
> 

P:=TravelingSalesman(G);

15471, [1, 19, 5, 6, 4, 14, 3, 10, 2, 22, 11, 25, 9, 20, 21, 24, 23, 15, 8, 12, 13, 7, 16, 18, 17, 1]

 (2)
> 

add(GetEdgeWeight(G,{P[2][i],P[2][i+1]}),i=1..nops(P[2])-1);

16570

 (3)
> 

 

> 

 

``


Download traveling_salesman_e.mw

Geometry: Why does it not find an inters...

Petra Heijnen 125
October 10 2013
2 2

THis is part of the code I used in the geometry package:

with(geometry):

circle(c,50811.89143+x^2+y^2-61.91881776*x-446.5619114*y = 0);

line(l,1621.451347-0.1838809e-1*x-7.2593834*y = 0):                               

draw([c,l]);
intersection(X,c,l,[F1,F2]);

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