Symbolic Unit Conversion Engine

Converts numeric values between units using a symbolic unit system, SI-derived expansions, and graph-based conversion for non-SI units.

Usage

convUnit(x, from, to, prefix = NULL, units = NULL)

Arguments

x

numeric value(s) to convert.

from

character string specifying the source unit.

to

character string specifying the target unit.

prefix

data frame of SI prefixes with columns abbr and mult.

units

data frame of unit conversion factors with columns from, to, and fact.

Value

Numeric value(s) converted to the target unit.

Details

Supports:

• SI base units (m, kg, s, A, K, mol, cd)

• Derived units (N, Pa, J, W, Hz)

• Prefixes (k, m, µ, etc.)

• Compound units (e.g. "km/h", "kg*m/s^2")

• Unit powers (e.g. "m2", "s^-1")

• Temperature conversion (C, F, K)

The function internally:

1. Parses units into symbolic components

2. Expands derived units (e.g. N = kg*m/s^2)

3. Computes dimensional vectors

4. Applies prefix scaling

5. Uses a graph search (Dijkstra) for non-SI conversions

The function checks dimensional consistency before conversion. If units are not compatible, an error is thrown.

For non-SI units (e.g. "mi", "bar"), conversion paths are resolved via a graph representation of Units.

Temperature conversions are handled separately and do not use multiplicative scaling.

See also

Other format: fm(), fmCI(), print.Unit(), style(), unit()

Examples

convUnit(100, "km/h", "m/s")
#> [1] 27.77778

convUnit(1, "N", "kg*m/s^2")
#> [1] 1
convUnit(1, "Pa", "N/m^2")
#> [1] 1
convUnit(25, "C", "F")
#> [1] 77
convUnit(1, "ml", "l")
#> [1] 0.001