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Electron Density Map File
The output file of the xrefin map statement contains
information about the unit cell, indexing of the map, and the actual electron
density map. It can be read by a modified version of MAPPAGE to provide
a “DSN6” file for FRODO. Modified versions of this
program are included in the
directory “[.VAX.FRODOMAP]" for the VAX/VMS system
and “sgi/fft" for the SGI systems. The grid size of the
map is determined
by the GRID parameter in the FFT statement.
The following is a FORTRAN example of how to read the
formatted (QFORM=.TRUE.) or unformatted
(QFORM=.FALSE.) version of the electron density
maps:
C C read title IF (QFORM) THEN READ(UNIT,'(/I8)',END=6,ERR=7) NTITLE IF (NTITLE .LE. 0) THEN READ( UNIT, '(A)',END=6,ERR=7) ELSE DO J = 1, NTITLE TITLE(J) = ' ' READ (UNIT, '(A)',END=6,ERR=7) TITLE(J) ENDDO ENDIF ELSE DO J=1,MXTITL TITLE(J)=' ' END DO READ(UNIT,END=6,ERR=7) NTITLE,(TITLE(J)(1:80),J=1,NTITLE) END IF C C read sectioning information IF (QFORM) THEN READ(U,'(9I8)',END=6,ERR=7) & NA,AMIN,AMAX,NB,BMIN,BMAX,NC,CMIN,CMAX ELSE READ(U,END=6,ERR=7) & NA,AMIN,AMAX,NB,BMIN,BMAX,NC,CMIN,CMAX END IF C C read unit cell constants in angstroms and degrees IF (QFORM) THEN READ(U,'(6E12.5)',END=6,ERR=7) (CELL(I),I=1,6) ELSE READ(U,END=6,ERR=7) (CELL(I),I=1,6) END IF END IF C C read matrix mode IF (QFORM) THEN READ(U,'(3A)',END=6,ERR=7) MODE ELSE READ(U,END=6,ERR=7) MODE END IF IF (MODE.NE.'ZYX') THEN CALL WRNDIE(-5,'RMAP','error in matrix mode') GOTO 7 END IF C C read density matrix, c is slowest ("z-sections"). DO C=CMIN,CMAX C C read next section IF (QFORM) THEN READ(U,'(I8)',END=6,ERR=7) KSECT READ(U,'(6E12.5)',END=6,ERR=7) & ((MAP(A,B,C),A=AMIN,AMAX),B=BMIN,BMAX) ELSE READ(U,END=6,ERR=7) KSECT READ(U,END=6,ERR=7) & ((MAP(A,B,C),A=AMIN,AMAX),B=BMIN,BMAX) END IF END DOThe following lines show the beginning of a typical electron density map file:
2 !NTITLE REMARKS FILENAME="" REMARKS DATE:18-Jun-90 12:24:08 created by user: XMAP: extend NA=( 30 4 12) NB=( 15 5 10) NC=( 16 2 12) 30 4 12 15 5 10 16 2 12 XMAP: a= 40.96, b= 18.65, c= 22.52, alpha= 90.00, beta= 90.77, gamma= 90.00 0.40960E+02 0.18650E+02 0.22520E+02 0.90000E+02 0.90770E+02 0.90000E+02 XMAP: written in ZYX mode (z-sections) ZYX XMAP: section # 0 average density=-0.336 sigma= 0.907 0 -0.97086E+00-0.49927E+00-0.82774E+00-0.13491E+01-0.57034E+00-0.71253E-01 -0.19491E+00 0.61017E+00 0.10064E+01-0.22888E+01-0.94020E+00 0.77451E+00 0.57539E+00-0.31211E-01-0.27430E+00-0.36526E+00 0.34772E+00 0.81884E+00 -0.19954E+01-0.10117E+01 0.18038E+01 0.19008E+01 0.11886E+00-0.41646E+00 0.47560E-01 0.48855E+00 0.57606E+00-0.22320E+00-0.12787E+01 0.47590E+00
Xplor-NIH 2024-09-13