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Re: Mathematica 9 does not read mathematica 8 ".mx" files
Posted:
Dec 17, 2012 2:53 AM
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On 14/12/2012 07:58, noomen mechri wrote: > Thanks for your reply! > yes, that's what I had to do ... rerun the whole calculation on M9 which > again took a few hours!! (I know ... not good at optimizing code) > But then what is the purpose of having .mx files to save the workspace > variables for future use ... if they can only be read by the version in > which they have been produced ... it is senseless ... > > > On Tue, Dec 11, 2012 at 9:03 PM, Bob Hanlon<hanlonr357@gmail.com> wrote: > >> I've never used an .mx file; however, from the documentation: >> >> "MX files cannot be exchanged between different operating systems or >> versions of Mathematica." >> >> "Mathematica MX files can be created with DumpSave and read with Get." >> >> Did you save the source files from which you did a DumpSave? If so, >> move the source files to v9 and DumpSave new .mx files in v9. >> >> >> Bob Hanlon >> >> >> On Tue, Dec 11, 2012 at 2:24 AM, NBM<noomenov@gmail.com> wrote: >>> Having written a lot of code on M8, I recently switched to M9 and tried >> to >>> run the code which starts by loading an .mx file written by M8, but M9 >> wouldn't read it saying that it was written on another machine. This is a >> major incompatibility issue between M8 and M9. Fortunately I kept my M8 >> installation, so for now, M9 is useless to me. >>> Please a solution. >>> >> > I hit the restriction with .mx files some time ago.
I really needed high speed, and I timed various alternatives. The best I found, was to write the data:
str=OpenWrite[file,BinaryFormat->True]; BinaryWrite[str,magic,"TerminatedString"]; BinaryWrite[str,Compress[{expr,version}],"TerminatedString"]; Close[str];
(where magic is a short string to use as a sanity check when reading back - omit if you prefer. expr is the large expression)
This can be read back with:
str=OpenRead[file,BinaryFormat->True]; If[BinaryRead[str,"TerminatedString"]==magic, expr=Uncompress[BinaryRead[str,"TerminatedString"]]; ]; Close[str];
The important point here, is that Compress and Uncompress are both fast and portable.
This isn't quite as fast as .mx files, but close!
David Bailey http://www.dbaileyconsultancy.co.uk
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