Modern Roman numerals

These two scripts, written in GNU Octave/Matlab language, convert Roman numerals to and from any integer (scalar, vector or matrix), including large numbers greater than 4999 with the parenthesis notation (multiplies by 1000).

num2roman.m

The function num2roman uses strict rules of modern notation (substractive principle for 4 and 9 bases) except for the common MMMM form replacing (IV).

Examples

>> num2roman(1968)
MCMLXVIII
>> % first power of 10
>> num2roman(10.^(0:7))
   'I'    'X'    'C'    'M'    '(X)'    '(C)'    '(M)'    '((X))'
>> % from 1 to 100
>> reshape(num2roman(1:100),10,10)'
'I'        'II'        'III'        'IV'        'V'        'VI'        'VII'        'VIII'        'IX'        'X'   
'XI'       'XII'       'XIII'       'XIV'       'XV'       'XVI'       'XVII'       'XVIII'       'XIX'       'XX'  
'XXI'      'XXII'      'XXIII'      'XXIV'      'XXV'      'XXVI'      'XXVII'      'XXVIII'      'XXIX'      'XXX'
'XXXI'     'XXXII'     'XXXIII'     'XXXIV'     'XXXV'     'XXXVI'     'XXXVII'     'XXXVIII'     'XXXIX'     'XL'  
'XLI'      'XLII'      'XLIII'      'XLIV'      'XLV'      'XLVI'      'XLVII'      'XLVIII'      'XLIX'      'L'   
'LI'       'LII'       'LIII'       'LIV'       'LV'       'LVI'       'LVII'       'LVIII'       'LIX'       'LX'  
'LXI'      'LXII'      'LXIII'      'LXIV'      'LXV'      'LXVI'      'LXVII'      'LXVIII'      'LXIX'      'LXX'
'LXXI'     'LXXII'     'LXXIII'     'LXXIV'     'LXXV'     'LXXVI'     'LXXVII'     'LXXVIII'     'LXXIX'     'LXXX'
'LXXXI'    'LXXXII'    'LXXXIII'    'LXXXIV'    'LXXXV'    'LXXXVI'    'LXXXVII'    'LXXXVIII'    'LXXXIX'    'XC'  
'XCI'      'XCII'      'XCIII'      'XCIV'      'XCV'      'XCVI'      'XCVII'      'XCVIII'      'XCIX'      'C'   

roman2num.m

roman2num is more flexible and is able to convert some other Roman notation possibilities, for instance the 3 different expressions IC,XCIX, and XCVIIII all return 99:

>> roman2num({'IC','XCIX','XCVIIII'})
    99    99    99

or the 2 expressions MDXV and MCCCCCXV both return 1515:

>> roman2num({'MDXV','MCCCCCXV'})
   1515   1515

Author

François Beauducel, IPGP, beaudu, [email protected]

Documentation

Type doc num2roman and doc roman2num for help and syntax.