Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    Name or NavList Code:
    Email:
       
    Reply
    Re: Yet another 4-place Nat-Haversine Table project?
    From: Brad Morris
    Date: 2018 Dec 8, 17:07 -0500
    Tony

    Roger's suggestion was the best (at least in my opinion, and yes, I do hold a degree in mathematics).

    Place a superscript exponent before the number, indicating how many leading zeros.  Its crisp.  Its clear.  It preserves all of the significant digits!

    Others, of course, are free to disagree

    Brad

    On Sat, Dec 8, 2018, 11:24 AM Tony Oz <NoReply_TonyOz@fer3.com wrote:

    Hello!

    I was thinking about the proposed - let's call it "scaling" - way to regain the resolution near the table's ends.

    I'm not the Mathematician to talk authoritatively here. My fear is that even if performed correctly (everywhere - on the table-creator's and on the table-user's sides) it could do more harm in the middle of the table.

    My reasoning: in the middle of the table (where there is more than three leading non-zeroes) the values are rounded. I use OpenOffice Calc (v4.1.5m1 build 9789 ref.1817495), which implements some well-recognised rounding method. I expect that the, say, multiplication of two numbers - one originally rounded in the 4th place, the other being re-scaled from  3rd place - the result will not be as good as one could expect. I'm not sure that after the multiplication result rounding all the noise would remain lower than the fifth place.

    So, at the cost of clearly making better resolution near the zero-end of the table we risk loosing the resolution in the middle. The near-1-end is also at risk.

    Not to say if the user makes a mistake in re-scaling the tabulated value.

    As a reason "I do it because I can" - I'll try to create such table, but the overall merit of such an enhancement must be properly discussed by professional Mathematicians.

    Please comment.

    Regards,

    Tony

    60°N 30°E

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site