http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Thu, 11 Jun 2026 22:54:57 GMT Thu, 11 Jun 2026 22:54:57 GMT The latest comments added to the Post, Implicit or Spherical http://www.mapleprimes.com/images/mapleprimeswhite.jpg http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical?ref=Feed:MaplePrimes:Implicit or Spherical:Comments#comment78989 I just wonder if -x^2*z*3 is intentional, or it meant to be -x^2*z^3 (the plots look similar) ? By the way, it is not related to the topic, but the standard angle limits in spherical coordinates are theta=0..2*Pi, phi=0..Pi. __________ Alec Mihailovs <a href="http://mihailovs.com/Alec/">http://mihailovs.com/Alec/</a> The latest comments added to the Post, Implicit or Spherical 78989 Wed, 22 Nov 2006 08:14:52 Z alec alec http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical?ref=Feed:MaplePrimes:Implicit or Spherical:Comments#comment86163 Alec. Many thanks for your comments. I should have checked the definition that Maple uses for spherical coordinates, but instead relied on what is probably an antique definition from my long-gone university days. It shouldn’t make any difference because the coordinates are an ordered triple. So, in principle, one could use (p, q, r) to mean (radius, co-latitude and longitude east) without confusing Maple (I hope) but almost certainly confusing everyone else, including me! The -x^2*z*3 term was intentional, but if replaced by -x^2*z^3, the timings remain much the same, though the plot looks nicer. Have you any thoughts on why the implicitplot is so much faster than the 3d spherical coords plot? All the best, J. Tarr The latest comments added to the Post, Implicit or Spherical 86163 Wed, 22 Nov 2006 17:36:58 Z Mariner Mariner http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical?ref=Feed:MaplePrimes:Implicit or Spherical:Comments#comment90988 My guess would be that the implicitplot was recently improved (it didn't work that great earlier, but it works much better now) while spherical plot is still using some old adaptive algorithm that goes into great detail near the singularity. Also, the functions plotted in implicitplot and in spherical plot, are different. Implicitplot is plotting a polynomial that should be handled very well by external libraries and evalhf, but the spherical plot is plotting RootOf that can not be handled by external libraries or evalhf. Which angle coordinate is which, can be seen from comparing 2 plots, <pre>plot3d(1,theta=0..2*Pi,phi=0..Pi/2, coords=spherical,scaling=constrained,axes=boxed); plot3d(1,theta=0..Pi/2,phi=0..2*Pi, coords=spherical,scaling=constrained,axes=boxed);</pre>Regards, __________ Alec Mihailovs <a href="http://mihailovs.com/Alec/">http://mihailovs.com/Alec/</a> The latest comments added to the Post, Implicit or Spherical 90988 Wed, 22 Nov 2006 20:31:17 Z Alec Mihailovs Alec Mihailovs http://www.mapleprimes.com/posts/42253-Implicit-Or-Spherical?ref=Feed:MaplePrimes:Implicit or Spherical:Comments#comment90994 I prefer to rely on Maple’s definition (see? sphericalcoords), which has a nice little figure to illustrate spherical coordinates. A minor curiosity is that Maple’s definition does not conform to ISO 31-11: it uses the “American” system. The differences are illustrated in wikepedia. J. Tarr The latest comments added to the Post, Implicit or Spherical 90994 Thu, 23 Nov 2006 22:05:12 Z Mariner Mariner