Numerical stability of cmap files

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Carsten
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Numerical stability of cmap files

Post by Carsten » 2005-12-09, 17:49

Hi all,

as we now have the TechDemo.cmap file in the Subversion repository, this is a good time to revise the numerical stability of the cmap file format.

That means that when I load a cmap into CaWE and then save it again, I want to obtain exactly the same file (which is an ascii text file as you know) as before.

This is not a strictly necessary requirement, but still very useful. It helps to keep the repository size small, because Subversion always only saves the differences between a revision and the next. Also, as you all know, I'm a hell of a mean guy who sometimes even runs
svn diff -r someXY:head TechDemo.cmap
and examines the output. :) That means I look at the text contents of the file to see what has changed. This is great for debugging many things. ;)

However, achieving this goal is pretty difficult, because high-precision output (many digits) and even the tiniest computations with the numbers between loading and saving them triggers e.g. a difference after e.g. the 10-th digit after the decimal.
And as I recently increased the precision of cmap files a lot, I was in severe trouble yesterday and today.
However, the problem is 90% solved, but I still keep the TechDemo.cmap file locked until I'm finished with the fixed code for overwriting it with a new version.

I've no time to finish this tonight (Friday), but will do so over the weekend.
Just wanted to let you know the latest status! :wink:
Have a nice WE! 8)
Best regards,
Carsten
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Carsten
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Posts: 2160
Joined: 2004-08-19, 13:46
Location: Germany
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Post by Carsten » 2005-12-09, 23:30

Okay, the problem is solved and the latest TD map is checked into the repository.
Please see
svn log -r 151:head
for details.
(Please remember that the server is normally down over weekends... sorry for that, but otherwise I had to sleep next to the running thing. ;) )
The only catch is that I had to introduce a new map file version for fixing this. That means that you'll need the latest CaWE exe to open the new map. :roll:
I'll prepare the download over the weekend though! Sorry for the inconvenience. :oops:
Best regards,
Carsten
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