parmed.unit.Quantity

class parmed.unit.Quantity(value=None, unit=None)

Physical quantity, such as 1.3 meters per second.

Quantities contain both a value, such as 1.3; and a unit, such as ‘meters per second’.

Supported value types include:

1 - numbers (float, int, long) 2 - lists of numbers, e.g. [1,2,3] 3 - tuples of numbers, e.g. (1,2,3)

Note - unit conversions will cause tuples to be converted to lists

4 - lists of tuples of numbers, lists of lists of … etc. of numbers 5 - numpy.arrays

Methods

in_unit_system(system)	Returns a new Quantity equal to this one, expressed in a particular unit system.
in_units_of(other_unit)	Returns an equal Quantity expressed in different units.
max(*args, **kwargs)	Computes the maximum value of the sequence, with the result having the same unit as the current sequence.
mean(*args, **kwargs)	Computes the mean of a sequence, with the result having the same unit as the current sequence.
min(*args, **kwargs)	Computes the minimum value of the sequence, with the result having the same unit as the current sequence.
reduce_unit([guide_unit])	Combine similar component units and scale, to form an equal Quantity in simpler units.
reshape(shape[, order])	Same as numpy.ndarray.reshape, except the result is a Quantity with the same units as the current object rather than a plain numpy.ndarray
sqrt()	Returns square root of a Quantity.
std(*args, **kwargs)	Computes the square root of the variance of a sequence, with the result having the same unit as the current sequence.
sum(*args, **kwargs)	Computes the sum of a sequence, with the result having the same unit as the current sequence.
value_in_unit(unit)	Returns underlying value, in the specified units.
value_in_unit_system(system)	Returns the underlying value type, after conversion to a particular unit system.

append
count
extend
format
index
insert
pop
remove

__init__(value=None, unit=None)

Create a new Quantity from a value and a unit.

Parameters

• value: (any type, usually a number) Measure of this quantity

• unit: (Unit) the physical unit, e.g. simtk.unit.meters.

Methods

__init__([value, unit])	Create a new Quantity from a value and a unit.
append(item)
count(item)
extend(rhs)
format(format_spec)
in_unit_system(system)	Returns a new Quantity equal to this one, expressed in a particular unit system.
in_units_of(other_unit)	Returns an equal Quantity expressed in different units.
index(item)
insert(index, item)
max(*args, **kwargs)	Computes the maximum value of the sequence, with the result having the same unit as the current sequence.
mean(*args, **kwargs)	Computes the mean of a sequence, with the result having the same unit as the current sequence.
min(*args, **kwargs)	Computes the minimum value of the sequence, with the result having the same unit as the current sequence.
pop(*args)
reduce_unit([guide_unit])	Combine similar component units and scale, to form an equal Quantity in simpler units.
remove(item)
reshape(shape[, order])	Same as numpy.ndarray.reshape, except the result is a Quantity with the same units as the current object rather than a plain numpy.ndarray
sqrt()	Returns square root of a Quantity.
std(*args, **kwargs)	Computes the square root of the variance of a sequence, with the result having the same unit as the current sequence.
sum(*args, **kwargs)	Computes the sum of a sequence, with the result having the same unit as the current sequence.
value_in_unit(unit)	Returns underlying value, in the specified units.
value_in_unit_system(system)	Returns the underlying value type, after conversion to a particular unit system.