nm

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13 years, 71 days

MaplePrimes Activity


These are replies submitted by nm

@vv 

Because this is separate and different question.  

This is asking why one needs to use simplify to make limit work and evaluate.

The other question asked why Limit did not work.

I find it hard to see how you think these are the same question. Just because the question is using same example, does not mean they are asking same thing.

At stackexchange this how things works. When one has a follow up and new question on a subject they asked (limit in this case), they are asked to open new question. No one there likes one to update their question and ask something more once the question is asked.

 

 

@ecterrab 

Thanks. But for some reason, I still get division by zero on my end. 


 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

Physics:-Version(latest);

`You already have the latest "Physics Updates" installed`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1780 and is the same as the version installed in this computer, created 2024, July 25, 8:56 hours Pacific Time.`

restart;

libname;

"C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib", "C:\Program Files\Maple 2024\lib"

ode:=diff(y(x),x$2)=(diff(y(x),x))^3-(diff(y(x),x))^2;
IC:=y(0)=3,D(y)(0)=1;

diff(diff(y(x), x), x) = (diff(y(x), x))^3-(diff(y(x), x))^2

y(0) = 3, (D(y))(0) = 1

dsolve([ode,IC])

Error, (in dsolve) numeric exception: division by zero

 


 

Download divide_by_zero_maple_V2_2024_1_august_6_2024.mw

I am on windows 10. I think you mentioned once that you use Mac, right? Could this make a difference? 

I closed Maple and opened twice, same result.  btw, I do not know why Physics:-Version() says that it was created on July 25,2024. Should not the date of V1780 be today August 6,2024? May be the update did not actually go through but only the version changed? I do not know.

I updated using the same way I always do, Physics:-Version(latest);  then closed all of Maple.

 

 

 

@Mariusz Iwaniuk 

Thanks., Easier workaround I found is to just call simplify on the original result which still had limit stuck in it. This causes limit to now evaluate. Strange behavior. Asked separate question on this.

@C_R 

Would you know by any chance a setting in Maple to make it work like the old way? This should be something that Maple can control. I mean cursor do not just jump to random location on its own. Somewhere in the Maple GUI code base should be setting or a way to control this. Unless this is Java own problem which Maple uses.

@Scot Gould 

smart plot in 2024.1 produces empty plot and also the worksheet is completely frozen after that. i.e. not able to issue any command. No response to anything I type afterwords. This is windows 10.


 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

restart;

sol:=1/2/cos(x)*(sin(x)^2+(sin(x)^4+36*cos(x))^(1/2));

(1/2)*(sin(x)^2+(sin(x)^4+36*cos(x))^(1/2))/cos(x)

smartplot(sol)

restart;


 

Download frozen_worksheet_after_smartplot.mw

 

@C_R 

"When exactly do you get this message? "

It happened this time when I opened a new worksheet and typed in command and hit evaluate.

I did not change any kernel options in this worksheet or do anything else. Since it is new worksheet, and I have option to use new engine with each worksheet, I assume Maple was trying to connect to either existing unused mserver.exe or start and connect to new one. And this is where this delay comes from.

Ive seen this before but it is very rare, so not a big deal for me. But this time it took long enough time that I was able to take screen shot of it while it was waiting.

@ecterrab 

Thanks for the quick fix. Confirmed OK.

Will also run more tests.

@ecterrab 

while when you set typesetting = standard (which is not Maple's default), that intercept mechanism is not present. 

But why it is not present? It was in Maple 2023. This issue is new in Maple 2024. I do not want to see such large display on the screen either.

How are users supposed to know that when using typesetting=standard, then accedential large output generated will end up hanging all of Maple?

Also the reason I changed long time ago to using standard is because of this known issue in display sometimes when using extended.

restart;

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

interface(typesetting=extended):

eq:=x-infinity=0;

x-infinity = 0

interface(typesetting=standard):

eq:=x-infinity=0;

x-infinity = 0

 

 

Download wrong_display_when_using_extended_maple_2024.mw

@acer 

When I removed the timelimit warapper around dsolve, then 

interface(typesetting=extended):
dsolve(ode);

returned back FAST, about 5 seconds, with the display `[Length of output exceeds limit of 1000000]`

When I did

interface(typesetting=standard):
dsolve(ode);

The result returned back but now it took 5 minutes and I do not get the `[Length of output exceeds limit of 1000000]` as before but now I get the actual large output. But Maple did not hang/freeze.  

So it looks also like Length of output calculation is affected by typesetting level. THis should not be the case.  The longer time must be because GUI was working on displying the result and not because dsolve() itself. 

Here is the updated worksheet. something is wrong somewhere. I will stop using typesetting=standard for now.

Will only post link to the worksheet, since output is very large,

maple_lock_up_july_17_2024_V_3.mw

@Carl Love 

Thanks. I also do not like aliases at all and never ever use them in Maple or any other language that allows them. They cause more problems than they solve. 

I changed all my code now to go back to old _C1 style. I added this one line at the top my my worksheet

dsolve(diff(y(x),x)=0,arbitraryconstants = traditional);

As the very first thing, and now things are working OK.

If I knew c__1 was an alias, I would have done this long time ago.  I overlooked this in help. I thought these were a brand new symbols that completely replace the old _C1 ones 

My fault for not knowing this difference more clearly. 

To show the kind of problems I was having when using subscripted, here is one example. In this, I have my own solution that I wrote, using subscripted symbols as the constant of integration.

When telling dsolve to use subscripted, odetest hangs. When telling dsolve to use traditional, odetest does not hang.

May you can see why. I can't. I asked Maple support to explain this, but never heard back from them.

If you can see why the second case hangs, it will be useful to know.

But since now I am back to using traditional for everything, this problem is gone. I am posting this example as a reference to kind of problems I started to see when I switched to subscripted.


 

interface(version)

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

``

 

 

 

Example that works when using traditional

 

 

restart;

dsolve(diff(y(x),x)=0,arbitraryconstants=traditional):

sol:=u(x)=(c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2))+2+(((c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2)))^2+2*(c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2))-(c__1*(1/x)^(2^(1/2)))^(2^(1/2))+3)^(1/2):
ode:=2^(1/2)*(u(x)*(u(x)+1)^2)^(1/2)+x*(2*u(x)-1)*diff(u(x),x)+2*u(x)^2-4*u(x) = 0:

st:=time[real]();
try
   timelimit(40,odetest(sol,ode));
catch:
   print("timed out ok");
end try:
print("time used is ",time[real]()-st," seconds ");

414.203

"time used is ", .242, " seconds "

 

Example  using subscripted. this HANGS

 

restart;

dsolve(diff(y(x),x)=0,arbitraryconstants=subscripted):
sol:=u(x)=(c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2))+2+(((c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2)))^2+2*(c__1*(1/x)^(2^(1/2)))^(1/2*2^(1/2))-(c__1*(1/x)^(2^(1/2)))^(2^(1/2))+3)^(1/2):
ode:=2^(1/2)*(u(x)*(u(x)+1)^2)^(1/2)+x*(2*u(x)-1)*diff(u(x),x)+2*u(x)^2-4*u(x) = 0:

st:=time[real]();
try
   timelimit(60,odetest(sol,ode));
catch:
   print("timed out ok");
end try:
print("time used is ",time[real]()-st," seconds ");

435.869

Warning,  computation interrupted

"time used is ", 6.561, " seconds "

 

 

 

 


 

Download test_timeout_sheet.mw

 

 

@C_R 

btw, your Maple build is is 1828976  but I am using Maple 2024.1 and it says build id is 1835466 which is different from what you show.

So you are using different Maple?. I thought you are using Maple 2024.1?  So that is why it does not hang for you but it does for me.

If you have Maple 2024.1 build id 1835466 then you can try that and see. 

 

@Axel Vogt 

FYI,

I did the same on Maple 2024.1 as you did. Saved it to MWS. But when I do print(e) Maple still hanged.

windows 10.

 

@C_R 

Which OS are you using, windows or mac or Linux?

For me, print(e) hangs Maple each time. I do not get the [Length of output....] message at all. As you see, it is set in options. I have not changed this.

Maple 2024.1 on windows 10.

I do not know why it hangs for me and not you for print(e). Are you saying it could be graphics card issue/setting?? That is very strange. Why would graphics card setting cause Maple frontend to hang?

As for the timelimit(), yes, this hangs all the time. I have to change my code now to check for length of expressio before calling expand. But timelimit should not hang.

 

 

@C_R 

I got that big expression in separate worksheet now.  But it is huge. I also found it makes Maple hangs in expand() even when using timelimit !

So I will post separate question on that, and you can use that expression there.  But if try to print it, it can hang Maple for you also.

I verified that Maple frontend hang when doing print on it. It should have generated that error message about a large expression over 100000.

Do not know why this does not happen in 2024.1 may be setting has changed. I know I did not change anything myself after the upgrade.

These are the type of problems I deal with all day with Maple. timelimit does not work all the time. Hangs when expressions are large and so on.

Maple has not improved in this area for a decade and more.

 

 

@C_R 

The problem was when I was doing 

  print(expr)

where expr has leaf count of 373134, which is very large.

When I commented this line out, the Maple front end hang is now gone.

THis is strange, becuase Maple should have generated that message that expression will be not display because its length is over 100000 or something like this. It could be that in Maple 2024.1 this limit is not active? I do not know.

NOthing special about my graphics card. I have NVIDIA  GEForce RTX 3060. Direct X 12.0 on windows 10.   128 GB RAM.

1 year old new PC. 

So to reproduce this hang, I just need to activate the print again on this large expression. So it should be possible to duplicate this by making very large random mathematical expression/equation and then try to print it in the worksheet and see what happens? 

 

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