- "We are doomed" - 7 Updates
| immibis <news@immibis.com>: Jan 22 01:22AM +0100 On 1/19/24 19:17, Malcolm McLean wrote: > be the same structures or incompatible structures. > But a simple standardisation would mean the end of pointless editing of > code just to conform to whatever the host program has chosen. And what should be the data type of the coefficients of the vector? And what should? Why not also have matrices? What is the maximum dimension supported? Are homogeneous coordinates a built-in feature? No, leave the graphics stuff to a graphics team. |
| Malcolm McLean <malcolm.arthur.mclean@gmail.com>: Jan 22 11:16AM On 22/01/2024 00:22, immibis wrote: > what should? Why not also have matrices? What is the maximum dimension > supported? Are homogeneous coordinates a built-in feature? No, leave the > graphics stuff to a graphics team. It should take a template, so any type can be used for the coefficients. Unless you have some weird and wonderful ideas, it will of course be scalar. I'd recommend a 2D with x and y and a 3D with x, y and z. Humanity is not going to be elevated to a higher dimension any time soon. No homogenous co-ordinates. No angle / magnitude notation. No need for matrices because we already have a natural representation of the these, since C++ supports 2 dimensional fixed size array. Needing to store points in 2D or 3D space is a common requirement, and code needs to communicate with other modules. One of which will be the graphics system, which may well have requirements beyond simple points in space, but will include such a requirement. -- Check out Basic Algorithms and my other books: https://www.lulu.com/spotlight/bgy1mm |
| Malcolm McLean <malcolm.arthur.mclean@gmail.com>: Jan 22 11:22AM On 21/01/2024 04:06, Kaz Kylheku wrote: > And that's just > [ c -d ] [ a ] = [ ca - db ] > [ d c ] [ b ] = [ da + cb ] Yes I know. I did complex numbers at high school. But whilst you could use the Argand plane as your graphics surface and thus represent all points as complex numbers, I've never actually seen anyone do so, and the axes are always given different labels. Except of course in Mandelbrots or other programs concerned with complex numbers themselves. -- Check out Basic Algorithms and my other books: https://www.lulu.com/spotlight/bgy1mm |
| "Fred. Zwarts" <F.Zwarts@HetNet.nl>: Jan 22 12:34PM +0100 Op 22.jan.2024 om 12:16 schreef Malcolm McLean: > code needs to communicate with other modules. One of which will be the > graphics system, which may well have requirements beyond simple points > in space, but will include such a requirement. According to Einstein, humanity lives already in a four dimensional space; time is the fourth dimension. There are many problems in physics and other fields with even more than 4 dimensions, so it would be short-sighted to limit the library to 3 dimensions. In addition one could ask how far the standard library must go. What operations must be supported? Calculate the length of a vector, allowing non-Euclidian spaces? |
| Malcolm McLean <malcolm.arthur.mclean@gmail.com>: Jan 22 12:31PM On 22/01/2024 11:34, Fred. Zwarts wrote: > In addition one could ask how far the standard library must go. What > operations must be supported? Calculate the length of a vector, allowing > non-Euclidian spaces? No-one is saying that you can't devise your own structures if you want to write programs to solve problems in general relativity. The idea is to have a common standard for the common requirement to represent pints and vectors in 2d and 3d spaces, so that routines writen in C++ can communicate with each other without the need for adapter code or rewriting. However having decided on a representation for points, there is also a very strong case for a standard library for basic operations on those points, such as taking the length of a vector. However probably not non-Euclidian spaces. Again, some people will want to write software that operates in Hilbert space or other non-Euclidean space, but it's likely to be specialised, and so you can't expect much support from the standard library. -- Check out Basic Algorithms and my other books: https://www.lulu.com/spotlight/bgy1mm |
| "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: Jan 22 12:22PM -0800 On 1/22/2024 3:22 AM, Malcolm McLean wrote: > anyone do so, and the axes are always given different labels. Except of > course in Mandelbrots or other programs concerned with complex numbers > themselves. Usually a vector, say 2-ary (x, y), x is the horizontal axis and y is the vertical axis. This matches a complex number x + yi: +y | -x--0--+x | -y x is real, y is imaginary. :^) |
| "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>: Jan 22 12:24PM -0800 On 1/22/2024 3:16 AM, Malcolm McLean wrote: > code needs to communicate with other modules. One of which will be the > graphics system, which may well have requirements beyond simple points > in space, but will include such a requirement. And 4-ary with (x, y, z, w) Again I am quite fond of the GLM library. It's just nice to me. |
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