Mathcad getting stuck

[HayleyW87]

I am having problems where mathcad seems to keep getting stuck when solving equations

I first noticed this problem when I half the time I tried to calculate my sheet, and I would notice mathcad would get "stuck" trying to multiply two matrices (one of the matrices is an inverse of another which mathcad had worked out prior). Once it gets stuck it wont ever finish and I cant stop the calculation without exiting mathcad entirely. This tended to happen about half the time I tried to calculate the sheet and the other half it would work fine, without spending hardly any time on that particular calculation.

Today I have also noticed it got "stuck" finding the eigenvalues of a matrix. I've tried copying and pasting to a new sheet and I still encounter similar problems.

This is becoming quite frustrating as the sheets can take a long time to do the calculations let alone when I end up wasting the time because it will get stuck later on in the sheet and I have to close it and start again

I am using mathcad 14 and my sheets do have a lot of calculations on them and any help on why mathcad does this and any way round it would be helpful

thanks

[MikeArmstrong]

Firstly welcome to the forum.

What size data are you handing? i.e. Matrix size?

Is it possible to post the worksheet?

Mike

[HayleyW87]

Unfortunately I cant post the worksheet as they are for work. Its basically a static FEA analysis with environmental loads on an object with approx 300 DoFs going onto a dynamic time analysis

The sheet is 2.4MB and the part that it tends to get stuck on at those points th matrices arent that big, only about 300x300. There are other places where there are vectors in matrices that can have 1000s of rows/columns where I havent had problems with it doing the calculations.

I also I can tend to have trouble sometimes when trying to save the worksheet, with a whole range of different warnings, but they tend to go away when I copy and paste into a new worksheet

[MikeArmstrong]

Without seeing the worksheet it won't be clearing what is causing the issue.

Richard usually gives a superb description on calculation speed and memory.

http://communities.ptc.com/message/155365#155365

If the above thread doesn't help, try searching through the forum for calculation speed or something similar.

There is a quicksheet for improving calculation speed which may be of help.

• Click help
  
• Quicksheets
  
• Mathcad techniques
  
• Improving calculation speed.
  

Hope the above helps.

Mike

[RichardJ]

Which version of 14 are you using?

As Mike says, without the worksheet it is impossible to say what is really happening. Try shutting down and restarting Mathcad before loading the worksheet. That shouldn't be necessary, but as noted in the thread Mike referenced, it seems that sometimes it is.

[mzeftel]

Richard is suggesting that you upgrade to at least Mathcad 14 M020, since if you have 14.0, we may have fixed something that is causing your problems.

You can upgrade if you have a maintenance account at https://www.ptc.com/appserver/cs/software_update/swupdate.jsp

If you don't have a maintenance account you can upgrade at http://www.ptc.com/support/mathcad_downloads.htm.

I hope this helps,

Mona

[RichardJ]

if you have 14.0, we may have fixed something that is causing your problems.

If it's the memory hogging problem described In that thread Mike referenced, unfortunately not. I ran those tests in version 15.

Of course, it could be something else though, and running the latest service release is (almost) always a good idea.

[VladimirN]

Hello!

What operating system do you use (what amount of RAM and processor speed)?

[HayleyW87]

I am already running Mathcad version 14.0 M020

I am using Windows XP Prof, with 4GB ram and 2.66GHz processor speed

I already use the techniqures in the Quicksheets to try and speed up my calculations as well

Today I am getting "Not enough memory for this operation message" in some of my larger functions (functions that produce vectors of a few million rows).

Other than speeding up functions, is there ways round these problems?

EDIT: I have temporarily changed to a different computer with Windows 7, 16Gb ram and i7 processor @ 2.93GHz. The mathcad sheet still has a memory error message in a similar place.

[RichardJ]

EDIT: I have temporarily changed to a different computer with Windows 7, 16Gb ram and i7 processor @ 2.93GHz. The mathcad sheet still has a memory error message in a similar place.

Above a certain point, it doesn't matter how much memory the computer has. A 32 bit application can only address a 2Gb virtual address space.

Other than speeding up functions, is there ways round these problems?

Maybe, although without seeing the worksheet there is no way to be sure. If you have a lot of intermediate results being calculated you should either change the worksheet to get rid of them or put the intermediate calculations into a program. Even if you use the same worksheet variable name for all the intermediate results, a second assignment to the name does not overwrite the contents of the first assignment. It creates a new copy of the variable, with it's own memory requirements, and there is no way for you to free that memory. However, if you put intermediate calculations in a program, then when the program exits the memory used by local program variables is freed.

[VladimirN]

Hayley Wear wrote:

I am already running Mathcad version 14.0 M020...

Try to install trial versions Mathcad 15 and Mathcad Prime 1.0 and to carry out the calculation in them.
Mathcad Prime 1.0: http://www.ptc.com/products/mathcad/mathcad-prime-1-0/free-trial.htm
Mathcad 15.0: http://www.ptc.com/products/mathcad/mathcad-15-0/free-trial.htm