Files
leonarski_fandClaude Opus 5.5 b17b643bd9 Readers: polarization from miniCBF and d*TREK headers (RESULT-CHANGING)
No reader parsed a polarization, and ApplyRugnuxExperimentDefaults then set
P = 0.99 (an undulator value) unconditionally, so laboratory-source data were
corrected as if from a synchrotron. Every d*TREK (Rigaku Saturn/A200) header in
the open arm states SOURCE_POLARZ=0.5 1 0 0, i.e. unpolarized; at Cu K-alpha and
2 A the wrong factor puts a +-33% azimuthal modulation on the intensities.

- d*TREK SMV: SOURCE_POLARZ is the fraction f followed by the plane normal (as
  dxtbx's FormatSMVRigaku reads it); stored as degree 2f - 1, negative where the
  normal lies along lab x (plane containing y).
- miniCBF: "# Polarization f" is the fraction in the horizontal plane; stored as
  2f - 1 ("None" or a missing line leave it unset).
- ApplyRugnuxExperimentDefaults sets 0.99 only where the file stated none;
  --polarization still overrides. ADSC SMV, marCCD and NXmx state nothing and
  keep 0.99.
- The "Header:" log line reports the stated polarization.

RESULT-CHANGING: d*TREK home-source sets (0.99 -> 0), one Rigaku miniCBF set
(0.99 -> 0), miniCBF sets stating 0.99 (0.99 -> 0.98).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PXc1zD1yxHqaR1DGdCTHL4
2026-10-18 09:25:14 +02:00

97 lines
4.7 KiB
C++

// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only
#pragma once
#include <array>
#include <cstdint>
#include <map>
#include <optional>
#include <string>
#include <vector>
// SMV: the format ADSC Quantum detectors wrote, and which Rayonix and several others still write.
// A plain ASCII header of "KEY=value;" lines between braces, then the pixels - no container, no
// compression, no binary header to decode by offset. The header states its own length, so even
// that is not assumed.
//
// {
// HEADER_BYTES= 512; DIM=2; BYTE_ORDER=little_endian; TYPE=unsigned_short;
// SIZE1=3072; SIZE2=3072; PIXEL_SIZE=0.102588; DISTANCE=250.000000;
// OSC_START=325.000000; OSC_RANGE=0.200000; WAVELENGTH=0.999839;
// BEAM_CENTER_X=157.500000; BEAM_CENTER_Y=157.500000;
// }
//
// Note the beam centre is in MILLIMETRES, not pixels, and its convention is the one thing writers
// disagree about - see the comment on beam_x_mm in the struct.
//
// Rigaku's d*TREK writes the same container with a different vocabulary: the detector and the
// goniometer as named circles with their vectors (CCD_GONIO_VALUES, ROTATION_VECTOR, ...), the beam
// position in pixels, and its own overflow encoding for 16-bit pixels. A header naming
// DETECTOR_NAMES is read that way.
namespace smv {
struct Header {
int64_t nx = 0; // SIZE1, the fast dimension
int64_t ny = 0; // SIZE2, the slow dimension
size_t data_offset = 0; // HEADER_BYTES
bool little_endian = true;
int64_t bytes_per_pixel = 2; // TYPE: unsigned_short
double pixel_x_m = 0;
double pixel_y_m = 0;
double distance_m = 0;
// BEAM_CENTER_X/Y, converted to pixels here. Writers disagree about this field more than about
// any other: it is in millimetres, and which of the two is the fast direction is a convention
// rather than a rule. Where a file also carries the ADSC-era synonyms (BEAM_CENTRE_X, or the
// MOSFLM-ordered pair) they are read too. A run whose centre is wrong is recoverable - the
// beam-centre estimator measures it from the data - but a wrong one is not detectable here.
double beam_x_px = 0;
double beam_y_px = 0;
double wavelength_A = 0;
double start_angle_deg = 0; // OSC_START, falling back to PHI
double angle_increment_deg = 0; // OSC_RANGE
double two_theta_deg = 0;
double exposure_s = 0;
int64_t saturation = 0; // CCD_IMAGE_SATURATION: the value a saturated pixel carries
std::string detector; // DETECTOR_SN, where stated
std::string axis_name = "phi";
// d*TREK only (Rigaku CrystalClear): the geometry is stated as vectors rather than the ADSC
// scalars, in the imgCIF laboratory frame - z from the sample to the source, y up. Absent on an
// ADSC header, where two_theta_deg above carries the one detector circle there is.
std::optional<std::array<double, 3>> fast_direction;
std::optional<std::array<double, 3>> slow_direction;
std::optional<std::array<double, 3>> spindle_axis;
struct Circle {
std::array<double, 3> axis;
double angle_deg;
};
std::vector<Circle> detector_circles; // header order: the outermost circle first
// SOURCE_POLARZ: the fraction of the beam polarized in a plane, and that plane's normal (the
// order XDS states FRACTION_OF_POLARIZATION and POLARIZATION_PLANE_NORMAL in). 0.5 is unpolarized.
std::optional<double> polarization_fraction;
std::optional<std::array<double, 3>> polarization_normal;
// RAXIS_COMPRESSION_RATIO: a stored value above 32767 is (value - 32768) * ratio. 0 = not used.
int64_t overflow_ratio = 0;
std::map<std::string, std::string> raw; // every key, for anything not modelled above
};
// True if the path names something this reader can open: an SMV file, or a directory holding at
// least one. Reads a few hundred bytes at most.
bool CanRead(const std::string &path);
// The files of one sweep, in collection order. path is a directory, or one frame inside it.
std::vector<std::string> CollectSweep(const std::string &path);
// Header only - reads just the leading brace block. Cheap enough to call per frame.
Header ReadHeader(const std::string &path);
// Header + pixels. out is resized to nx * ny.
Header Read(const std::string &path, std::vector<int32_t> &out);
// The same, widening the stored pixels into memory the caller already has. scratch carries the
// raw bytes between frames so a worker walking a sweep allocates once - on Windows only; elsewhere the
// file is mapped and scratch is not used.
Header ReadInto(const std::string &path, int32_t *out, size_t capacity, std::vector<uint8_t> &scratch);
} // namespace smv