News for hackers. Stuff that matters.

A comment on Conway's Game of Life, using floating point values instead of integers. Parent comment

Re:Conway's Game of Life, using floating point values instea... by ghostfish on Thursday October 11, 2012 @07:52PM (#4643341)
As far as I'm aware OpenCL performance, while portable, is still somewhat inferior to that of straight CUDA on NVIDIA GPUs, hence my CUDA suggestion. I didn't actually look at the algorithms used in either so I can't comment, perhaps I'll do that tomorrow. What do you mean by using an FFT "for" a convolution? The algorithm is convolving the (presumably 2D) FFT of the game board with a disk filter?
[ Parent | on HN ]
Re:Conway's Game of Life, using floating point values instea... by tim_hutton on Friday October 12, 2012 @04:40AM (#4644238)
SmoothLife uses two disks around each point to determine the instantaneous rate of change. Inside each disk the values are summed. This is a convolution with a disk filter.

http://en.wikipedia.org/wiki/Convolution

As it says on that page, FFT is often used for convolution because it is fast: after applying a discrete Fourier transform to the kernel and the image, the resulting images must only be multiplied together before applying an inverse FFT.

http://en.wikipedia.org/wiki/Discrete_Fourier_transform

[ Parent | on HN ]
Re:Conway's Game of Life, using floating point values instea... by ghostfish on Friday October 12, 2012 @03:09PM (#4646406)
Ah, thanks for the information. I'm familiar with signal processing, so the only way I'm used to seeing convolutions is through the multiplication of FFTs. I wasn't even considering the "regular" way.
[ Parent | on HN ]
Re:Conway's Game of Life, using floating point values instea... by tomrod on Friday October 12, 2012 @10:01AM (#4645046)
That's so cool. I love to see real world applications of convolutions.

I wonder if there is an application of Gershgorin's Disc theorem here?

[ Parent | on HN ]
Re:Conway's Game of Life, using floating point values instea... by tim_hutton on Friday October 12, 2012 @11:50AM (#4645539)
I see something about a circle that contains the eigenvectors of a matrix. How does that apply here?
[ Parent | on HN ]