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 | 1 | initial version |
The rounding are not the same as shown below (or the precision are different, I do not know):
sage: a = RR(1/10)
sage: a.sign_mantissa_exponent()
(1, 7205759403792794, -56)
sage: (a * RR(10)).sign_mantissa_exponent()
(1, 4503599627370496, -52)
sage: b = RDF(1/10)
sage: b.sign_mantissa_exponent() # same floating point as above
(1, 7205759403792793, -56)
sage: (b * RDF(10)).sign_mantissa_exponent() # different from above !!
(1, 9007199254740991, -53)
In particular, RR has the equality 1/10 * 10 = 1 but not RDF because
sage: RR(1).sign_mantissa_exponent()
(1, 4503599627370496, -52)
sage: RDF(1).sign_mantissa_exponent()
(1, 4503599627370496, -52)
| | 2 | added comma for clarity: "not the same, as shown below" vs "not the same as shown below" |
The rounding are Rounding in RR and RDF is not the same same, as shown below (or the precision are is different, I do not know):
sage: a = RR(1/10)
sage: a.sign_mantissa_exponent()
(1, 7205759403792794, -56)
sage: (a * RR(10)).sign_mantissa_exponent()
(1, 4503599627370496, -52)
sage: b = RDF(1/10)
sage: b.sign_mantissa_exponent() # same floating point as above
(1, 7205759403792793, -56)
sage: (b * RDF(10)).sign_mantissa_exponent() # different from above !!
(1, 9007199254740991, -53)
In particular, RR has the equality 1/10 * 10 = 1 but not RDF because
sage: RR(1).sign_mantissa_exponent()
(1, 4503599627370496, -52)
sage: RDF(1).sign_mantissa_exponent()
(1, 4503599627370496, -52)
