bignum math library

Tom Glod tom at makeshyft.com
Sun Nov 18 17:20:52 EST 2018


very impressed ..thank you.

On Sun, Nov 18, 2018 at 1:29 PM Geoff Canyon via use-livecode <
use-livecode at lists.runrev.com> wrote:

> I've created bignum libraries in the past, but never organized it or did
> all four operators. So I started with earlier versions of some of the
> functions, optimized, corrected, and extended, and here it is:
> https://github.com/gcanyon/bignum
>
> It includes functions for addition, subtraction, multiplication, division,
> and comparison/equals. All functions handle any length of argument. Most
> have options that handle signed arguments. The functions are optimized for
> things like different-length arguments.
>
> Some performance benchmarks on my five-year-old laptop:
>
> Add two 10,000 digit numbers: 0.005 seconds.
> Add two 10,000 digit numbers: 0.004 seconds.
> Multiply two 10,000 digit numbers: 3.1 seconds.
> Divide a 10,000 digit number by a 5,000 digit number: 9.4 seconds -- needs
> some optimization.
>
> For division in particular, I wrote a faster algorithm that is included,
> but there is a bug in the final steps that I haven't figured out yet.
> bigDivFlawed is about 40% faster than bigDiv, but can bork the last few
> digits of the quotient. Included in case anyone sees the logic error.
>
> If anyone has any suggestions, let me know here, or file bug reports on
> github, or code and submit a pull request.
>
> A list of the functions included:
>
>
> function bigAdd -- returns the sum
> function bigAddSigned -- handles positive and negative arguments
> function bigSubtract -- returns the difference
> function bigSubtractSigned -- handles positive and negative arguments
> function bigTimes -- returns the product
> function bigTimesSigned -- handles positive and negative arguments
> function bigDiv -- returns (the integer quotient),(the remainder)
> function bigDivSigned -- handles positive and negative arguments
> function bigishDiv -- Handles any length dividend; divisor must be a valid
> LC number (< 16 digits)
> function bigDivFlawed -- About 40% faster than bigDiv, but can bork the
> last few digits of the quotient. Included in case anyone sees the logic
> error.
> function bigCompare -- Applies >,<,=,<=,>= to any length arguments
> function stripLeadingZeros -- returns any string without whatever leading
> zeros it contains
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