K
Kevin Olbrich
Announcing......
Ruby Units
Version: 0.1.0
Kevin C. Olbrich, Ph.D.
http://www.sciwerks.com
Project page: http://rubyforge.org/projects/ruby-units
==Introduction
Many technical applications make use of specialized calculations at some
point. Frequently, these calculations require unit conversions to
ensure accurate results. Needless to say, this is a pain to properly
keep track of, and is prone to numerous errors.
==Solution
The 'Ruby units' gem is designed so simplify the handling of units for
scientific calculations. The units of each quantity are specified when
a Unit object is created and the Unit class will handle all subsequent
conversions and manipulations to ensure an accurate result.
==Installation:
This package may be installed using:
gem install ruby-units
==Usage:
unit = Unit.new("1") # constant only
unit = Unit.new("mm") # unit only (defaults to a value of 1)
unit = Unit.new("1 mm") # create a simple unit
unit = Unit.new("1 mm/s") # a compound unit
unit = Unit.new("1 mm s^-1") # in exponent notation
unit = Unit.new("1 kg*m^2/s^2") # complex unit
unit = Unit.new("1 kg m^2 s^-2") # complex unit
unit = Unit("1 mm") # shorthand
unit = "1 mm".to_unit # convert string object
unit = object.to_unit # convert any object using object.to_s
==Rules:
1. only 1 quantity per unit (with 2 exceptions... 6'5" and '8 lbs 8 oz')
2. use SI notation when possible
3. avoid using spaces in unit names
==Unit compatability:
Many methods require that the units of two operands are compatible.
Compatible units are those that can be easily converted into each other,
such as 'meters' and 'feet'.
unit1 =~ unit2 #=> true if units are compatible
==Unit Math:
Unit#+():: Add. only works if units are compatible
Unit#-():: Subtract. only works if units are compatible
Unit#*():: Multiply.
Unit#/():: Divide.
Unit#**():: Exponentiate. Exponent must be an integer, can be
positive, negative, or zero
Unit#inverse:: Returns 1/unit
Unit#abs:: Returns absolute value of the unit quantity. Strips off
the units
Unit#ceil:: rounds quantity to next highest integer
Unit#floor:: rounds quantity down to next lower integer
Unit#round:: rounds quantity to nearest integer
Unit#to_int:: returns the quantity as an integer
Unit will coerce other objects into a Unit if used in a formula. This
means that ..
Unit("1 mm") + "2 mm" == Unit("3 mm")
This will work as expected so long as you start the formula with a Unit
object.
==Conversions & comparisons
Units can be converted to other units in a couple of ways.
unit1 = unit >> "ft" # => convert to 'feet'
unit >>= "ft" # => convert and overwrite original object
unit3 = unit1 + unit2 # => resulting object will have the units of unit1
unit3 = unit1 - unit2 # => resulting object will have the units of unit1
unit1 <=> unit2 # => does comparison on quantities in base
units, throws an exception if not compatible
unit1 === unit2 # => true if units and quantity are the same,
even if 'equivalent' by <=>
==Text Output
Units will display themselves nicely based on the preferred abbreviation
for the units and prefixes.
Since Unit implements a Unit#to_s, all that is needed in most cases is:
"#{Unit.new('1 mm')}" #=> "1 mm"
The to_s also accepts some options.
Unit.new('1.5 mm').to_s("%0.2f") # => "1.50 mm". Enter any valid
format string
Unit.new('1.5 mm').to_s("in") # => converts to inches before printing
Unit.new("2 m").to_s
ft) #=> returns 6'7"
Unit.new("100 kg").to_slbs) #=> returns 220 lbs, 7 oz
Feedback is welcome, as are feature suggestions.
This release covers most SI, imperial, and customary units.
_Kevin
www.sciwerks.com
Ruby Units
Version: 0.1.0
Kevin C. Olbrich, Ph.D.
http://www.sciwerks.com
Project page: http://rubyforge.org/projects/ruby-units
==Introduction
Many technical applications make use of specialized calculations at some
point. Frequently, these calculations require unit conversions to
ensure accurate results. Needless to say, this is a pain to properly
keep track of, and is prone to numerous errors.
==Solution
The 'Ruby units' gem is designed so simplify the handling of units for
scientific calculations. The units of each quantity are specified when
a Unit object is created and the Unit class will handle all subsequent
conversions and manipulations to ensure an accurate result.
==Installation:
This package may be installed using:
gem install ruby-units
==Usage:
unit = Unit.new("1") # constant only
unit = Unit.new("mm") # unit only (defaults to a value of 1)
unit = Unit.new("1 mm") # create a simple unit
unit = Unit.new("1 mm/s") # a compound unit
unit = Unit.new("1 mm s^-1") # in exponent notation
unit = Unit.new("1 kg*m^2/s^2") # complex unit
unit = Unit.new("1 kg m^2 s^-2") # complex unit
unit = Unit("1 mm") # shorthand
unit = "1 mm".to_unit # convert string object
unit = object.to_unit # convert any object using object.to_s
==Rules:
1. only 1 quantity per unit (with 2 exceptions... 6'5" and '8 lbs 8 oz')
2. use SI notation when possible
3. avoid using spaces in unit names
==Unit compatability:
Many methods require that the units of two operands are compatible.
Compatible units are those that can be easily converted into each other,
such as 'meters' and 'feet'.
unit1 =~ unit2 #=> true if units are compatible
==Unit Math:
Unit#+():: Add. only works if units are compatible
Unit#-():: Subtract. only works if units are compatible
Unit#*():: Multiply.
Unit#/():: Divide.
Unit#**():: Exponentiate. Exponent must be an integer, can be
positive, negative, or zero
Unit#inverse:: Returns 1/unit
Unit#abs:: Returns absolute value of the unit quantity. Strips off
the units
Unit#ceil:: rounds quantity to next highest integer
Unit#floor:: rounds quantity down to next lower integer
Unit#round:: rounds quantity to nearest integer
Unit#to_int:: returns the quantity as an integer
Unit will coerce other objects into a Unit if used in a formula. This
means that ..
Unit("1 mm") + "2 mm" == Unit("3 mm")
This will work as expected so long as you start the formula with a Unit
object.
==Conversions & comparisons
Units can be converted to other units in a couple of ways.
unit1 = unit >> "ft" # => convert to 'feet'
unit >>= "ft" # => convert and overwrite original object
unit3 = unit1 + unit2 # => resulting object will have the units of unit1
unit3 = unit1 - unit2 # => resulting object will have the units of unit1
unit1 <=> unit2 # => does comparison on quantities in base
units, throws an exception if not compatible
unit1 === unit2 # => true if units and quantity are the same,
even if 'equivalent' by <=>
==Text Output
Units will display themselves nicely based on the preferred abbreviation
for the units and prefixes.
Since Unit implements a Unit#to_s, all that is needed in most cases is:
"#{Unit.new('1 mm')}" #=> "1 mm"
The to_s also accepts some options.
Unit.new('1.5 mm').to_s("%0.2f") # => "1.50 mm". Enter any valid
format string
Unit.new('1.5 mm').to_s("in") # => converts to inches before printing
Unit.new("2 m").to_s
ft) #=> returns 6'7"Unit.new("100 kg").to_s
lbs) #=> returns 220 lbs, 7 ozFeedback is welcome, as are feature suggestions.
This release covers most SI, imperial, and customary units.
_Kevin
www.sciwerks.com