In SAMSON, physical quantities are strongly typed. All physical quantities have associated Units.


The full list of these units can be seen in the SAMSON SDK: SBDQuantity.

These units should be used as input data for functions from SAMSON API whenever it is necessary.

These units are exposed in the samson.SBQuantity sub-module in such a way, that you can operate with these units, do most of the arithmetic operations with them, and pass them into functions.


The samson.SBQuantity sub-module contains Python bindings for SBDQuantity from SAMSON SDK - it allows you to operate with them, create your own quantities, and do arithmetic operations.

Please refer to the SBQuantity section for more information and the list of available classes.

Python scripting exposes a number of classes that define basic types used in SAMSON, in particular for mathematical operations.

# create a position vector in length units
pos = SBPosition3(0.0, 1.0, 2.0)
# this is the same as
pos = SBPhysicalVector3(SBQuantity.position(0.0), SBQuantity.position(1.0), SBQuantity.position(2.0))

# arithmetic operations with numbers, units, and vectors
pos /= 2.0
pos * 1.5

# accessing components
pos.x             # x-component of the vector
pos.x = 2 * pos.y
pos[0]            # x-component of the vector
pos.value         # components of the vector (read-only)

# operations with vectors
pos.norm()            # returns norm of a vector

pos += SBPhysicalVector3(SBQuantity.angstrom(1))

time = SBQuantity.femtosecond(1)
# this will create a velocity vector in proper length/time units
velocity = pos / time

# position in angstroms
pos2 = SBPhysicalVector3(

Please refer to the Type section for more information and the list of available classes.