Brix is a program (Still Another!) to convert different formats of electron density maps to O format. Brix was written to circumvent the problems of fixed array boundaries, and allocates the memory it needs on the fly. Thus, you are only limited by the virtual memory of the computer.
Brix writes a new un-swapped version of the DSN6 file, independent of endianism issues. Thus, you can use a bricked density file which has been calculated on an ALPHA machine on a SGI. Also, the new format contains more information in the header, most notably the SIGMA value of the map. Thus, in your map macros, you will be able to put a `;' where you normally specify the contouring level, to get a 1 sigma contouring.
The new bricked electron density format is understood by versions of O later than 5.9.2.
However, Brix will still calculate the old, unportable, DSN6 format, if the program is invoked under the name mappage (uh, actually, it only needs to *contain* the word mappage, so 4d_mappage is OK). In other words, you can install a symbolic link (or normal link):
% ln -s brix mappage
and then run the mappage version.
Brix understands the following map formats: X-PLOR (formatted), CCP4, TNT and EZD, it will automagically determine which format the map is, and allocate the right amount of memory. It will also automatically slice the map correctly.
Here is a sample session of Brix. The only input needed is the names of the input map and the output brick file; these can be given on the command line:
kaktus 395% brix /xtal/morten/xplor/type3/m10.xmap m10.omap brix> Convert ED maps to O format brix> Version 1.1, Nov 1993 brix> brix> Mapfile: /xtal/morten/xplor/type3/m10.xmap brix> O brick file: m10.omap brix> ...file is formatted brix> brix> Map type is X-PLOR brix> brix> Parameters as read from the map file: brix> Grid ................. 80 80 192 brix> Origin ............... 6 -21 24 brix> Extent ............... 75 105 76 brix> Fast, medium, slow.... 1 2 3 brix> Cell axes ............ 69.90 69.90 161.80 brix> Cell angles .......... 90.00 90.00 90.00 brix> brix> Reslicing XYZ --> YXZ brix> Fast, medium, slow.... 2 1 3 brix> Min, max, sigma ...... -4.53080 7.12510 0.98377 brix> Scale ................ 1.000 brix> brix> Prod ................. 21.87733 brix> Plus ................. 99 brix> Bricks along x,y,z ... 10 14 10 kaktus 396%
TNT maps do not store the cell parameters, so in that case the user will be prompted for the missing information.