That's because I was trying to illustrate the difference between the abstract mathematical definition and an implementation suitable for computer graphics. I had just asked Glen if he grokked the difference and he said no. --- Frank C. Wimberly 140 Calle Ojo Feliz, Santa Fe, NM 87505
505 670-9918 Santa Fe, NM On Thu, Jul 23, 2020, 4:27 PM Angel Edward <[email protected]> wrote: > You keep talking in terms of implementations rather than the abstract > object. > > Here you say a square does not include information about its location but > then you add the location in the class definition. In coordinate-free > geometry, you have only three basic entities: scalars, points and vectors. > You can use them to define all the standard geometric objects and write > code purely in terms of these entities. > > Ed > __________ > > Ed Angel > > Founding Director, Art, Research, Technology and Science Laboratory (ARTS > Lab) > Professor Emeritus of Computer Science, University of New Mexico > > 1017 Sierra Pinon > Santa Fe, NM 87501 > 505-984-0136 (home) [email protected] > 505-453-4944 (cell) http://www.cs.unm.edu/~angel > > On Jul 23, 2020, at 4:09 PM, Frank Wimberly <[email protected]> wrote: > > The mathematical concept of a point in R^2 is that a it is completely > determined by the values of its coordinates. Same coordinates, same > point. A square per se Is determined by the length of its side(s). There > is no information about it's location. > > If I were writing a Square class for a graphics application I would > include two member variables: > > LocationOfLowerLeft point; > LengthOfSide double; > > I haven't written code for years so beware. > > --- > Frank C. Wimberly > 140 Calle Ojo Feliz, > Santa Fe, NM 87505 > > 505 670-9918 > Santa Fe, NM > > On Thu, Jul 23, 2020, 3:58 PM uǝlƃ ↙↙↙ <[email protected]> wrote: > >> No, I don't. What's the difference? >> >> On 7/23/20 2:46 PM, Frank Wimberly wrote: >> > OK. As long as you grok the difference between the mathematical >> concept and the OO concept. >> >> -- >> ↙↙↙ uǝlƃ >> >> - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . >> FRIAM Applied Complexity Group listserv >> Zoom Fridays 9:30a-12p Mtn GMT-6 bit.ly/virtualfriam >> un/subscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> archives: http://friam.471366.n2.nabble.com/ >> FRIAM-COMIC <http://friam.471366.n2.nabble.com/FRIAM-COMIC> >> http://friam-comic.blogspot.com/ >> > - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . > FRIAM Applied Complexity Group listserv > Zoom Fridays 9:30a-12p Mtn GMT-6 bit.ly/virtualfriam > un/subscribe http://redfish.com/mailman/listinfo/friam_redfish.com > archives: http://friam.471366.n2.nabble.com/ > FRIAM-COMIC http://friam-comic.blogspot.com/ > > > - .... . -..-. . -. -.. -..-. .. ... -..-. .... . .-. . > FRIAM Applied Complexity Group listserv > Zoom Fridays 9:30a-12p Mtn GMT-6 bit.ly/virtualfriam > un/subscribe http://redfish.com/mailman/listinfo/friam_redfish.com > archives: http://friam.471366.n2.nabble.com/ > FRIAM-COMIC http://friam-comic.blogspot.com/ >
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