new format for BLAST Magnetic Field

From: Timothy Smith (tim_smith@mit.edu)
Date: Mon Sep 17 2001 - 14:21:14 EDT


Hello BLASTers,

        The Blast Software now accepts a second format for the
magnetic field files. In the original form there was information
for half of one sector, the other sectors field being derived
for rotational and mirror reflection. But we realized that in the
near future we will be measuring a field map, which will not
be so symmetric. Therefore, after a discussion at the last BLAST
Software meeting (Sept 7) a second format was designed, and has
now been implemented and tested. The details of this format are at
the end of this note.

        **A Few Notes**

        -> If you continue to use the original "bgrid.blast", things
will continue to work as they have.

        -> "blastmc" and "libBlast.so" (which is the heart of all
fields) recognize both formats.

        -> Most code ("blastmc", "nsed", "s") still expect the name
"bgrid.blast".

        -> If you Monte Carlo with format #2, also reconstruct with
format #2.

        -> You can get a copy of the field map in this format from
the cvs repository, in the new directory Blast_Prams. The file
is called "bgrid2.blast".

        -> **THE ONLY THING WHICH NEEDS CHANGING TO RUN FORMAT #2 IS**;
in the input file for "blastmc" (fort.32, or something like that)
the line "MAGN"

(format #1)
MAGN 'TABL' 'POFF' 'BSCL' 0.12

(format #2)
MAGN 'TABL' 'POFF' 'BSCL' 1.0

Now, if the last number is "1.0" that means "full field",
half field is "0.5", reversed field is "-1.0", etc.

        Please get back to me if there are any problems.

                                Tim Smith
____________________________________________________________________
 Timothy Paul Smith Research Scientist
 MIT Bates Lab tim_smith@mit.edu
 21 Manning Rd. tel: (617) 253-9207
 Middleton, MA 01949 fax: (617) 253-9599

===================================================================

Details of "format #2"
Distances are in centimeters
The Magnitude of the Field is in units of kilo-Gauss

#2
xmin nx dx
ymin ny dy
zmin nz dz
Bx(xmin,ymin,zmin) By(xmin,ymin,zmin) Bz(xmin,ymin,zmin)
Bx(xmin+dx,ymin,zmin) By(xmin+dx,ymin,zmin) Bz(xmin+dx,ymin,zmin)
Bx(xmin+dx*2,ymin,zmin) By(xmin+dx*2,ymin,zmin) Bz(xmin+dx*2,ymin,zmin)
  .
  .
  .
Bx(xmin+dx*nx,ymin,zmin) By(xmin+dx*nx,ymin,zmin) Bz(xmin+dx*nx,ymin,zmin)
Bx(xmin,ymin+dy,zmin) By(xmin,ymin+dy,zmin) Bz(xmin,ymin+dy,zmin)
Bx(xmin+dx,ymin+dy,zmin) By(xmin+dx,ymin+dy,zmin) Bz(xmin+dx,ymin+dy,zmin)
Bx(xmin+dx*2,ymin+dy,zmin) By(xmin+dx*2,ymin+dy,zmin) Bz(xmin+dx*2,ymin+dy,zmin)
  .
  .
  .
Bx(xmin+dx*nx,ymin+dy*ny,zmin+dz*nz) By(xmin+dx*nx,ymin+dy*ny,zmin+dz*nz) Bz(

My example files looks like;

#2
-310 63 10.0
-160 33 10.0
-210 53 10.0
1.966473e-08 -8.163747e-05 -8.137008e-08
2.642096e-04 1.367731e-03 3.165924e-04
3.247841e-04 1.675746e-03 4.071602e-04
.
.
.



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