Units and dimensionality

MoDaCor uses one application-wide Pint registry, exported as modacor.ureg. Addition and subtraction require compatible units. Multiplication and division derive result units normally, so counts divided by seconds becomes counts per second and intensity divided by solid angle gains inverse-steradian units.

Unit conversion applies the same multiplicative factor to the signal and every absolute uncertainty. Offset-unit conversion is deliberately rejected because uncertainties would require an explicit delta-unit policy.

rank_of_data describes how many trailing dimensions carry the scientific data grid:

• 0: scalar metadata or a correction factor;

• 1: a curve;

• 2: an image; and

• 3: a volume.

Leading dimensions can represent repeated frames or scan positions. The rank must be between zero and three and cannot exceed signal.ndim.

Detector element coordinates are indices. MoDaCor therefore treats pixel, px, dot, and related aliases as dimensionless detector-coordinate units. Detector pitch remains a physical length such as m, mm, or um.