Lets say this can somehow work (which it won't)

v^2:= a^2 + b^2

Then later on, you write v:=5;   Then next you write print(v^2) 

What should Maple print? 

@radaar 

my purpose is to speed up the computation.

if you are using hardware floating points, why do you think if the numbers all have first 10 decimal points not zero, and last 5 are zero, then the calculation will be faster than if all numbers had all 15 decimal points non zero? 

Are you saying the time to do a hardware calculation depends on how many zeros there are in the the  CPU register?

I am not following how less decimal places will make hardware calculations faster?

@Carl Love 

opps, yes, I read it as evalf. Need new glasses. That is why it will be best if OP provides an example, in that case I would have copied it and not made this mistake. But it should still work with evalhf? I mean the truncation part. Will correct

@acer 

Thanks. My question remains the same which you answered. I only added explaining WHY I needed this transformation and where I wanted to use it, that is all. I did not add a new question.

Will try your suggestion on the whole Laplacian now.

Thanks for help

@ecterrab 

V 350 worked for me also, no more error.

Thanks for all your work on this.

@tomleslie 

Thanks for checking.

On "OP suggests issue might be a Windows 10 update??"

No,  I said the above about why I do not install Physics package using the cloud instead of manual download. 

Not related to the error message I get from Maple running the code. I was answering the other reply asking me to try to install Physics package again. May be I should have been more clear.

But I am glad someone other than me is able to produce this error message.

@itsme 

THank you for the suggestion. I tried all these things before. It does not work. This is a known long standing problem.  I am not the only one who seen this

https://www.mapleprimes.com/questions/226651-Why-Still-Not-Able-To-Install-Physics

It might be related to windows 10 professional change in some latest update and due to changing some file permissions.

There is nothing wrong with how I install the physics package. It is something I've been doing the same steps for a year now. I download the physics package itself and put in

Then edit maple.ini in lib folder:

and add the line

libname := "C:\\Maple_updates\\maple_2019\\Physics_Updates_348.maple", libname:

I am following the instruction thanks to Edgardo S. Cheb-Terrab as given in bottom of this post

https://www.mapleprimes.com/questions/226154-Installing-Packages-From-The-Cloud-Hangs

So I am sure I am using Physics package 348. That what Version() says.

As to why I get this error on my Maple, I have no idea. But will be happy to try any suggestion in order to find out why.

@ecterrab 

Thank you for checking. But it does not work for me. I am also using Physics 348 and Maple 2019 on windows 10.

I downloaded version 348 yesterday and followed same steps I always do to use new version. So I do not know why it works for you and not for me. 

If there is something else you like me to check please let me know.

I can't install Maple packages using the CLOUD interface directly, due to a bug somewhere. Maple server crash each time I try, and have to manually download the physics package and then adjust maple.ini to point to new version. This is what I been doing for more than a year now due to this bug in the cloud/windows issue.

Download it_does_not_work_for_me.mw

@acer 

But this can lead to many programming errors.

If a function expects A,B,C in that order, and if one of them happend to be empty/null, then the arguments get shifted without the caller knowing this.

Suppose the caller was getting the result "A" from  as return result from a call to another function, and they want to pass these arguments to another function (like I did) for more processing, then they have to check each time that each of the arguments they are passing along is not null before making the call.  And if it is null, what will they replace it with, so that the order of arguments does not get shuffled during the call?

I find this not a good design in Maple to tell you the truth. A null or () should be passed as it is and not be removed from the call. 

It might not be possible for Maple to do that, but that is another issue. I am just saying what should happen.

@Rouben Rostamian  

Thanks. THere is no such file in the Maple 2019 folder on windows 10. I searched for the file using windows search tool and it did not find anythere. I also searched the Maple 2018 folder, nothing there.

This seems to be for the mac only.

@itsme 

Thanks. I know about this option, but I am reading the string from database (sqlite).

@ecterrab 

Ok, I deleted the whole toolbox/2019  then started Maple and did Physics:-Version(333)

But to due to the issue of Maple not copying the .maple file to "toolbox\2019\Physics Updates" itself, due to some permission problem or something else with windows, I have no choice but to copy the .maple file manually over to "toolbox\2019\Physics Updates" from the temp download folder.

And the issue is still there after starting Maple. Nothing changed. That print out msg still shows.

But if it works for others, it is not a problem really for me as pdsolve still works fine and gives solution, so this msg showing has no effect on me.

Thank you

@ecterrab 

Thank you for the update.  But the issue is still there in 333:

I downloaded version 333 to the Physics Updated folder OK.

Restarted Maple, etc... The message still shows up. Also in the Int example you showed as well. Still there.

May be someone else could try it just in case.

@ecterrab 

On my system it always says  "version installed in this   computer: the "Physics Updates" is not installed" this is because I download the Physics package manually and put it in separate folder then update the maple.ini to point to it. So the file

C:\Program Files\Maple 2018\lib\maple.ini contains this line

         libname := "C:\\Maple_updates\\Physics_Updates_319.maple", libname:

This works, per your suggestion in this post  Installing-Packages-From-The-Cloud-Hangs

Since I am not able to install the Physics package using the cloud interface for some reason which I could not figure out why. But manual download works thanks to your suggestion. But a side effect of this, is that now Physics:-Version() says

Physics:-Version()
 "C:\Maple_updates\Physics_Updates_319.maple", 2019, March 3, 
    17:7 hours, version in the MapleCloud: 319, version installed in this 
    computer: the "Physics Updates" is not  installed.

But it is using version 319, which I downloaded to C:\Maple_updates\Physics_Updates_319.maple

@acer 

"What if you try and pass resource limits (time, data limit) for the kernel when you launch Maple?"

Sorry, but I have no idea what you mean by the above. How would one tell Maple to use some specific time limit on all calls to pdsolve at Launch time?

I have a loop when I run over some problems, and I want to set timelimit to each and obtain the time used for each.  I only want to set timelimit on the call to pdesolve. I do not want to set time limit for any other calls. It is like this

for N from 1 to 100 do
     #some other Maple code here that do not want to set timelimit on or measure its time
     #read pde
    cpu_time := timelimit(180,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
od;
     

What interface/client are you using? GUI? TTY/CLI?

Worksheet mode. Not CLI. I open Maple GUI, open new worksheet and run the code there. The problem is that if I do not set timelimit, some problems will hang. And if I set timelimit, some problems will still hang (but not all) as it depends on the amount of the timelimit set.