MaplePrimes - comments on Blog Entry, More Gems from the Little Red Book of Maple Magic

MaplePrimes - comments on Blog Entry, More Gems from the Little Red Book of Maple Magic http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Thu, 11 Jun 2026 00:30:01 GMT Thu, 11 Jun 2026 00:30:01 GMT The latest comments added to the Blog Entry, More Gems from the Little Red Book of Maple Magic http://www.mapleprimes.com/images/mapleprimeswhite.jpg MaplePrimes - comments on Blog Entry, More Gems from the Little Red Book of Maple Magic http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic for Gem 6 http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic?ref=Feed:MaplePrimes:More Gems from the Little Red Book of Maple Magic:Comments#comment102327 For Gem 6 one may wish to consider 'signum' as well, since 'is' is expensive: <pre>  if 0 < signum(2*sqrt(2)) then print(yes) else print(no) end if;                                 yes </pre> Note that signum(0) = 0, signum(0.0) = 0.0 I also made the experience that this also might work for long and complicated expressions, where 'is' needed so long, that I killed it. PS: I like that 'gems' series. PPS: one can not copy code from your post, since that are images (thus needs the appended *.mw sheet) The latest comments added to the Blog Entry, More Gems from the Little Red Book of Maple Magic 102327 Wed, 09 Mar 2011 00:57:43 Z Axel Vogt Axel Vogt Gem 7 http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic?ref=Feed:MaplePrimes:More Gems from the Little Red Book of Maple Magic:Comments#comment102332 I would avoid the solution of using Typesetting[Settings] because this will cause problems if you try to communicate with somebody who doesn't use the same settings.  Rather than trying to remember all the complications of when you do or don't need an explicit multiplication (space or *), it's by far preferable to stick to a simple infallible rule: always use explicit multiplication.  The latest comments added to the Blog Entry, More Gems from the Little Red Book of Maple Magic 102332 Wed, 09 Mar 2011 02:07:51 Z Robert Israel Robert Israel signum http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic?ref=Feed:MaplePrimes:More Gems from the Little Red Book of Maple Magic:Comments#comment102338 <a href="http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic#comment102327">@Axel Vogt</a>  The single argument signum is not reliable because of this "strange" property, after <a href="http://www.maplesoft.com/support/help/search.aspx?term=signum:">?signum:</a> <blockquote> The value of signum(0) is controlled by the environment variable _Envsignum0. If _Envsignum0 is not assigned a value, then signum(0) is not defined, in that it can evaluate to anything. </blockquote> Then, in my opinion, it is better to use the three argument version where the value is well defined: <pre>signum(0,0,0), signum(0,0.0,0); 0, 0 </pre> Indeed, it seems the form most frequently used in the library code. I agree, a text form for input would be much more convenient than images, both for direct copy&paste and for reduced load time (so long for my taste, that I tend to avoid clicking on these blogs). Besides, the result is not so aesthetic anyway as the inline formulas appear misaligned with the surrounding text. The latest comments added to the Blog Entry, More Gems from the Little Red Book of Maple Magic 102338 Wed, 09 Mar 2011 06:33:16 Z Alejandro Jakubi Alejandro Jakubi algsubs and multiple replacements http://www.mapleprimes.com/maplesoftblog/102311-More-Gems-From-The-Little-Red-Book-Of-Maple-Magic?ref=Feed:MaplePrimes:More Gems from the Little Red Book of Maple Magic:Comments#comment102497 The limitation of algsubs for multiple replacements can be somewhat worked around by using foldr like: <pre>q1:=sin(a*b*k)+(a*b*k)^2: foldr(algsubs,q1,k*c=d,a*b=c); 2 d + sin(d) </pre> Certainly, algsubs is a most important command for these symbolic computations, and it is a pitty that its development has been frozen (or so) for about 15 years. The latest comments added to the Blog Entry, More Gems from the Little Red Book of Maple Magic 102497 Sun, 13 Mar 2011 04:12:26 Z Alejandro Jakubi Alejandro Jakubi