# Revision history [back]

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" slelievre 8977 ●6 ●91 ●175 http://carva.org/samue...

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)