On 3/15/12 9:05 AM, William Stein wrote:
On Thu, Mar 15, 2012 at 6:53 AM, Daniel Krenn<[email protected]> wrote:
How do I change the default precision used? E.g. I want to enter {{{a
= 1.2}}} and want that a is an element of RealField(100) without
explicitly telling to use that field each time.
What does not work is:
sage: RR = RealField(100)
sage: a = 1.2
sage: a.parent()
Real Field with 53 bits of precision
You could do the following to force any floating point number entered
to have exactly 100 bits of precision by default:
sage: RealNumber = lambda x: RealField(100)(x)
sage: 2.5
2.5000000000000000000000000000
sage: 4.2992038490283409823094820938492834082093482834
4.2992038490283409823094820939
Or, you could even force all the floating point numbers that you enter
to be intervals with 100 bits of precision:
sage: RealNumber = lambda x: RealIntervalField(100)(x)
sage: 2.5
2.5000000000000000000000000000000?
sage: sin(2.5)
0.598472144103956494051854702186?
I'm curious: why do you use lambda functions?
sage: RealNumber = RealField(100)
sage: (1.2).parent()
Real Field with 100 bits of precision
sage: RealNumber = RealIntervalField(100)
sage: (1.2).parent()
Real Interval Field with 100 bits of precision
Thanks,
Jason
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