Module: Measurand::Format

Defined in:
lib/Measurand/Format.rb

Class Method Summary collapse

Class Method Details

.decimals(place) ⇒ Object 



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# File 'lib/Measurand/Format.rb', line 39

def decimals(place)
  place < 0 ? -place : 0
end

.round_to_place(number, place) ⇒ Object 



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# File 'lib/Measurand/Format.rb', line 34

def round_to_place(number, place)
  factor = 10.0 ** place
  (number / factor).round * factor
end

.round_uncertainty(uncertainty) ⇒ Object

Returns [rounded_uncertainty, place], where place is the power of ten of the least significant shown digit (negative for digits after the point).



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# File 'lib/Measurand/Format.rb', line 19

def round_uncertainty(uncertainty)
  exponent = ::Math.log10(uncertainty).floor
  leading = (uncertainty / 10.0 ** (exponent - 2)).round
  if leading < 355
    significant_figures = 2
  elsif leading < 950
    significant_figures = 1
  else
    significant_figures = 2
    exponent += 1
  end
  place = exponent - significant_figures + 1
  [round_to_place(uncertainty, place), place]
end