cdm/src/main/java/ucar/nc2/units/SimpleUnit.java
static public double getConversionFactor(String inputUnitString, String outputUnitString) throws IllegalArgumentException {
    SimpleUnit inputUnit = SimpleUnit.factory(inputUnitString);
    SimpleUnit outputUnit = SimpleUnit.factory(outputUnitString);
    return inputUnit.convertTo(1.0, outputUnit);
  }
static public double getConversionFactor(String inputUnitString, String outputUnitString) throws IllegalArgumentException {
    SimpleUnit inputUnit = SimpleUnit.factory(inputUnitString);
    SimpleUnit outputUnit = SimpleUnit.factory(outputUnitString);
    return inputUnit.convertTo(1.0, outputUnit);
  }
Get the conversion factor to convert inputUnit to outputUnit.

@param inputUnitString  inputUnit in string form
@param outputUnitString outputUnit in string form
@return conversion factor
@throws IllegalArgumentException if not convertible