Class: Rational

Inherits:
Numeric show all
Defined in:
opal/opal/corelib/rational.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Numeric

#%, #+@, #-@, #__coerced__, #abs2, #angle, #clone, #conj, #div, #divmod, #dup, #fdiv, #finite?, #i, #imag, #infinite?, #integer?, #negative?, #nonzero?, #polar, #positive?, #real, #real?, #rect, #to_c, #to_int, #zero?

Methods included from Comparable

#<, #<=, #>, #>=, #between?, #clamp

Constructor Details

#initialize(num, den) ⇒ Rational

Returns a new instance of Rational.



48
49
50
51
 
# File 'opal/opal/corelib/rational.rb', line 48

def initialize(num, den)
  @num = num
  @den = den
end

Class Method Details

.convert(num, den) ⇒ Object 



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'opal/opal/corelib/rational.rb', line 22

def self.convert(num, den)
  if num.nil? || den.nil?
    raise TypeError, 'cannot convert nil into Rational'
  end

  if Integer === num && Integer === den
    return reduce(num, den)
  end

  if Float === num || String === num || Complex === num
    num = num.to_r
  end

  if Float === den || String === den || Complex === den
    den = den.to_r
  end

  if den.equal?(1) && !(Integer === num)
    Opal.coerce_to!(num, Rational, :to_r)
  elsif Numeric === num && Numeric === den
    num / den
  else
    reduce(num, den)
  end
end

.reduce(num, den) ⇒ Object 



4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
# File 'opal/opal/corelib/rational.rb', line 4

def self.reduce(num, den)
  num = num.to_i
  den = den.to_i

  if den == 0
    raise ZeroDivisionError, 'divided by 0'
  elsif den < 0
    num = -num
    den = -den
  elsif den == 1
    return new(num, den)
  end

  gcd = num.gcd(den)

  new(num / gcd, den / gcd)
end

Instance Method Details

#*(other) ⇒ Object 



144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
 
# File 'opal/opal/corelib/rational.rb', line 144

def *(other)
  case other
  when Rational
    num = @num * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num * other, @den)

  when Float
    to_f * other

  else
    __coerced__ :*, other
  end
end

#**(other) ⇒ Object 



186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
 
# File 'opal/opal/corelib/rational.rb', line 186

def **(other)
  case other
  when Integer
    if self == 0 && other < 0
      Float::INFINITY
    elsif other > 0
      Rational(@num**other, @den**other)
    elsif other < 0
      Rational(@den**-other, @num**-other)
    else
      Rational(1, 1)
    end

  when Float
    to_f**other

  when Rational
    if other == 0
      Rational(1, 1)
    elsif other.denominator == 1
      if other < 0
        Rational(@den**other.numerator.abs, @num**other.numerator.abs)
      else
        Rational(@num**other.numerator, @den**other.numerator)
      end
    elsif self == 0 && other < 0
      raise ZeroDivisionError, 'divided by 0'
    else
      to_f**other
    end

  else
    __coerced__ :**, other
  end
end

#+(other) ⇒ Object 



106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
 
# File 'opal/opal/corelib/rational.rb', line 106

def +(other)
  case other
  when Rational
    num = @num * other.denominator + @den * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num + other * @den, @den)

  when Float
    to_f + other

  else
    __coerced__ :+, other
  end
end

#-(other) ⇒ Object 



125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
 
# File 'opal/opal/corelib/rational.rb', line 125

def -(other)
  case other
  when Rational
    num = @num * other.denominator - @den * other.numerator
    den = @den * other.denominator

    Rational(num, den)

  when Integer
    Rational(@num - other * @den, @den)

  when Float
    to_f - other

  else
    __coerced__ :-, other
  end
end

#/(other) ⇒ Object Also known as: divide, quo 



163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
 
# File 'opal/opal/corelib/rational.rb', line 163

def /(other)
  case other
  when Rational
    num = @num * other.denominator
    den = @den * other.numerator

    Rational(num, den)

  when Integer
    if other == 0
      to_f / 0.0
    else
      Rational(@num, @den * other)
    end

  when Float
    to_f / other

  else
    __coerced__ :/, other
  end
end

#<=>(other) ⇒ Object 



90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
 
# File 'opal/opal/corelib/rational.rb', line 90

def <=>(other)
  case other
  when Rational
    @num * other.denominator - @den * other.numerator <=> 0

  when Integer
    @num - @den * other <=> 0

  when Float
    to_f <=> other

  else
    __coerced__ :<=>, other
  end
end

#==(other) ⇒ Object 



74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
# File 'opal/opal/corelib/rational.rb', line 74

def ==(other)
  case other
  when Rational
    @num == other.numerator && @den == other.denominator

  when Integer
    @num == other && @den == 1

  when Float
    to_f == other

  else
    other == self
  end
end

#abs ⇒ Object 



222
223
224
 
# File 'opal/opal/corelib/rational.rb', line 222

def abs
  Rational(@num.abs, @den.abs)
end

#ceil(precision = 0) ⇒ Object 



226
227
228
229
230
231
232
 
# File 'opal/opal/corelib/rational.rb', line 226

def ceil(precision = 0)
  if precision == 0
    (-(-@num / @den)).ceil
  else
    with_precision(:ceil, precision)
  end
end

#coerce(other) ⇒ Object 



61
62
63
64
65
66
67
68
69
70
71
72
 
# File 'opal/opal/corelib/rational.rb', line 61

def coerce(other)
  case other
  when Rational
    [other, self]

  when Integer
    [other.to_r, self]

  when Float
    [other, to_f]
  end
end

#denominator ⇒ Object 



57
58
59
 
# File 'opal/opal/corelib/rational.rb', line 57

def denominator
  @den
end

#floor(precision = 0) ⇒ Object 



236
237
238
239
240
241
242
 
# File 'opal/opal/corelib/rational.rb', line 236

def floor(precision = 0)
  if precision == 0
    (-(-@num / @den)).floor
  else
    with_precision(:floor, precision)
  end
end

#hash ⇒ Object 



244
245
246
 
# File 'opal/opal/corelib/rational.rb', line 244

def hash
  "Rational:#{@num}:#{@den}"
end

#inspect ⇒ Object 



248
249
250
 
# File 'opal/opal/corelib/rational.rb', line 248

def inspect
  "(#{self})"
end

#numerator ⇒ Object 



53
54
55
 
# File 'opal/opal/corelib/rational.rb', line 53

def numerator
  @num
end

#rationalize(eps = undefined) ⇒ Object 



254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
 
# File 'opal/opal/corelib/rational.rb', line 254

def rationalize(eps = undefined)
  %x{
    if (arguments.length > 1) {
      #{raise ArgumentError, "wrong number of arguments (#{`arguments.length`} for 0..1)"};
    }

    if (eps == null) {
      return self;
    }

    var e = #{eps.abs},
        a = #{self - `e`},
        b = #{self + `e`};

    var p0 = 0,
        p1 = 1,
        q0 = 1,
        q1 = 0,
        p2, q2;

    var c, k, t;

    while (true) {
      c = #{`a`.ceil};

      if (#{`c` <= `b`}) {
        break;
      }

      k  = c - 1;
      p2 = k * p1 + p0;
      q2 = k * q1 + q0;
      t  = #{1 / (`b` - `k`)};
      b  = #{1 / (`a` - `k`)};
      a  = t;

      p0 = p1;
      q0 = q1;
      p1 = p2;
      q1 = q2;
    }

    return #{Rational(`c * p1 + p0`, `c * q1 + q0`)};
  }
end

#round(precision = 0) ⇒ Object 



300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
 
# File 'opal/opal/corelib/rational.rb', line 300

def round(precision = 0)
  return with_precision(:round, precision) unless precision == 0
  return 0 if @num == 0
  return @num if @den == 1

  num = @num.abs * 2 + @den
  den = @den * 2

  approx = (num / den).truncate

  if @num < 0
    -approx
  else
    approx
  end
end

#to_f ⇒ Object 



317
318
319
 
# File 'opal/opal/corelib/rational.rb', line 317

def to_f
  @num / @den
end

#to_i ⇒ Object 



321
322
323
 
# File 'opal/opal/corelib/rational.rb', line 321

def to_i
  truncate
end

#to_r ⇒ Object 



325
326
327
 
# File 'opal/opal/corelib/rational.rb', line 325

def to_r
  self
end

#to_s ⇒ Object 



329
330
331
 
# File 'opal/opal/corelib/rational.rb', line 329

def to_s
  "#{@num}/#{@den}"
end

#truncate(precision = 0) ⇒ Object 



333
334
335
336
337
338
339
 
# File 'opal/opal/corelib/rational.rb', line 333

def truncate(precision = 0)
  if precision == 0
    @num < 0 ? ceil : floor
  else
    with_precision(:truncate, precision)
  end
end

#with_precision(method, precision) ⇒ Object

Raises:



341
342
343
344
345
346
347
348
349
350
351
352
 
# File 'opal/opal/corelib/rational.rb', line 341

def with_precision(method, precision)
  raise TypeError, 'not an Integer' unless Integer === precision

  p = 10**precision
  s = self * p

  if precision < 1
    (s.send(method) / p).to_i
  else
    Rational(s.send(method), p)
  end
end