The d*TREK reflnlist format is extensible much like the MTZ format. There are binary and ASCII versions. I think that for a start, I'll describe just the file that is output at the end by our scaling and averaging program. This file is the one most users will use for subsequent steps. The file is ASCII free-format and consists of the following lines: Line 1: 3 or 4 integer numbers The first 3 numbers represents the number of fields or columns per reflection. 1st number: Number of integer fields: NumInts 2nd number: Number of float fields: NumFloats 3rd number: Number of string fields: NumStrings The fourth number, NumInfoLines, may not be present. It represents the number of lines of additional header text that follows the first line. If absent, this number should be set to 0. If NumInfoLines is not 0, then NumInfoLines containing d*TREK header keyword=value(s); information follows. If NumInfoLines is 0, then there are no such lines. Presently, these lines contain information about the crystal unit cell and spacegroup. In the future, these lines could contain an entire standard d*TREK header which could fully describe the experiments and processing to yield the reflns in the file. Lines 2+NumInfoLines .... These contain left-justified the names of the refln fields or columns. Field names have no white space; one field name per line. Integer field names begin with the letter n; float field names with the letter f; string field names with the letter s. There will be NumInts + NumFloats + NumStrings fieldnames. The first 3 integer field names MUST be nH, nK, nL. The first 2 float field names MUST be fIntensity and fSigmaI. All integer fields come before any float fields. All string field follow any float fields. Lines 2+NumInfoLines + NumInts + NumFloats + NumStrings ... These are the actual reflns. Reflns MUST contain h, k, l as integers and Intensity and SigmaI as floats. All other fields are optional. Any strings cannot have whitespace. The reflns MUST have a value for every field. The values -1.0 and -999.0 are often used as fillers. All values are in free format and NOT RESTRICTED NOR ALIGNED IN ANY COLUMNS. Next is a short example of a reflnlist file produced by dtscaleaverage: =====this is an example reflnlist file====(do not include this line)=== 3 6 0 5 CRYSTAL_DESCRIPTION=unknown; CRYSTAL_MOSAICITY=0.7807 0.0000 0.0000; CRYSTAL_ORIENT_ANGLES= 7.3764 -13.6663 -11.2194; CRYSTAL_SPACEGROUP=89; CRYSTAL_UNIT_CELL= 78.6619 78.6619 36.9993 90.0000 90.0000 90.0000; nH nK nL fIntensity fSigmaI fIntensity+ fSigmaI+ fIntensity- fSigmaI- 0 0 2 14.9526 51.0419 14.9526 51.0419 -1.00000 -1.00000 0 0 3 112.983 44.0395 99.7694 71.9012 119.599 50.8736 0 0 4 45164.7 2055.19 45164.7 2055.19 -1.00000 -1.00000 0 0 5 100.449 52.7485 100.449 52.7485 -1.00000 -1.00000 0 0 6 45.1334 57.8072 45.1334 57.8072 -1.00000 -1.00000 0 0 7 104.904 75.1638 104.904 75.1638 -1.00000 -1.00000 0 0 8 46159.0 1567.61 46159.0 1567.61 -1.00000 -1.00000 2 1 16 3622.38 130.607 3380.38 172.233 3935.93 196.389 2 1 17 3799.84 133.226 4082.16 193.255 3543.54 183.439 2 2 1 39556.5 871.160 40230.6 1249.37 38917.1 1214.40 2 2 2 43025.1 1156.39 43240.7 2109.55 42863.4 948.015 ======================do not include this line either ============== The fields fIntensity+, fSigmaI+, fIntensity-, fSigmaI- hold values for the anomalous intensity information. The values fIntensity and fSigmaI hold the properly weighted average for Intensity and sigmaIntensity. The fields fIntensity+, fSigmaI+, fIntensity-, fSigmaI- MAY NOT ALWAYS BE PRESENT in the file since this is under user control. A zero or negative value for any Sigma means the intensity:sigma pair is not valid and should be considered absent or rejected. Negatives values for Intensity are allowed and valid if the corresponding sigma is positive. Values of (-1, -1) for (Intensity, Sigma) mean the measurement is absent. Centric reflections will still have I+ and I- measurements even though this should be equivalent. Here is another example file: =====this is an example reflnlist file====(do not include this line)=== 3 6 0 nH nK nL fIntensity fSigmaI 0 0 2 14.9526 51.0419 0 0 3 112.983 44.0395 0 0 4 45164.7 2055.19 ======================do not include this line either ==============