From: TOYOFUKU Chikanobu <nobu_toyofuku@...>
Date: 2008-10-09T22:33:07+09:00
Subject: [ruby-dev:36695] Re: [IA-64]BigDecimal#sqrt 	の仕様

  豊福です。

In [ruby-dev:36662]
> - assert_equal(1125899906842624, x.sqrt(100))
> - assert_equal(1125899906842624, x.sqrt(200))
> - assert_equal(1125899906842624, x.sqrt(300)) # I don't understand the meaning of argument...
> + assert_equal(true, x.sqrt(100) - x.sqrt(200) > x.sqrt(300) - x.sqrt(400))

  y = BigDecimal("1125899906842624")
  prec = y.precs[0]
  assert_equal(true, (x.sqrt(100) - y).abs < BigDecimal("1E#{prec-100}"))
  assert_equal(true, (x.sqrt(200) - y).abs < BigDecimal("1E#{prec-200}"))
  assert_equal(true, (x.sqrt(300) - y).abs < BigDecimal("1E#{prec-300}"))

はどうでしょう。
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