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Help page for sqrt

alec's picture
Posted on 2008-06-24 13:26 By alec (Maple Rating 4 1476)
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I'd like to see the following examples in the help page for sqrt,

sqrt(149^3);

                        149*sqrt(149);

sqrt(151^3);

                        sqrt(3442951);

Alec

‹ Information about the User Dictionary in Help copying and pasting several lines of code into Standard Maple ›
Robert Israel's picture

Magic number

Comment on 2008-06-24 15:04 from Robert Israel (Maple Rating 4 1431)

This comes from the line

 h := igcd(y, `sqrt/primes`);

where `sqrt/primes` is the product of primes from 2 to 149.

Try this:

> `sqrt/primes`:= `sqrt/primes`*151;
   sqrt(151^3);

 

alec's picture

Magic numbers in help pages

Comment on 2008-06-24 15:20 from alec (Maple Rating 4 1476)

I've discovered that the same way - looking at the sqrt code and trying to improve it for integers - thus far, the code that I wrote works about twice faster (for integers) than current sqrt , but I'd like to have something, say, 10 times faster, and without using compiled code.

Such magic numbers - in this case, it is the product of prime numbers from 2 to 149, should be mentioned on the help pages, I think.

Alec

JacquesC's picture

Magic numbers

Comment on 2008-06-26 23:14 from JacquesC (Maple Rating 4 1697)

An additional problem with these magic numbers is that their size were set a very very very long time ago.  Computers have changed a lot since, but these have not been revisited.  Whatever criteria were used for setting these has likely been forgotten, so I guess no one even knows how to go about adapting them to modern hardware capabilities.

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