Yes I am still alive... :) I've been exceptionally busy at work lately, not complaining though as work pays the bills and gpu / compute things are just a hobby.
What I do find rather frustrating is in the limited time I have to maintain the blog, it all gets eaten up by wading through mountains of spam. Akismet does a fantastic job, but on the forums side the bot detection captcha is pathetic and I have around 100 signups / 100's of messages to check every day. So until a later date when I can fix / upgrade it I will be suspending the forums from today.
On a rather more positive note: Nvidia has announced OptiX ray tracing engine. Some examples are out already so worth having a look at. Nvidia has also announced Nexus which looks incredible. I have heard that they may charge for it but with the features it apparently has I would be willing to pay.
For some of the latest conferences papers and pre-prints have a look at Ke-Sen Huang's page which he keeps updated with some really nice stuff.
As for me - no new cuda / compute development for a while. When I get a few mins free I'm tending to work on the maths for the stuff I want to do but never get enough time to implement anymore. Hopefully this will change in 2 or 3 months once work settles down a bit. On the subject of work there have been one or two questions over email and on the blog of the steps taken after an edge detector has been applied - unfortunately I cannot answer this as it gets a bit close to what I do for work (OCR and document processing). Rather interesting one of my ray tracing acceleration algorithms which turned out pathetically for its purpose has been rather good at identifying features in 2d/3d images but more on this at a later date once its a bit more complete.
Friday, 25 September 2009
Thursday, 30 July 2009
3D Gaussian Convolution
There hasn't been much in the way of posts here lately as I've been really busy at work getting some new components built into the systems I work on. Not really hard but it's frustrating things like trying to get various components and libraries written in different languages to work together. So lately I've not had the energy to do much work on the computer once I get home...
There has been a bit of interest in my 3D Gaussian convolution kernels. Although I explained the technique mathematically in an earlier post I never actually posted the code. As it is rather quick and quite a novel way of calculating the convolution for a xy plane I decided to post it so everyone can benefit from / improve upon the technique. As always comments / bug reports etc are always welcome :)
There has been a bit of interest in my 3D Gaussian convolution kernels. Although I explained the technique mathematically in an earlier post I never actually posted the code. As it is rather quick and quite a novel way of calculating the convolution for a xy plane I decided to post it so everyone can benefit from / improve upon the technique. As always comments / bug reports etc are always welcome :)
Thursday, 23 July 2009
Happy blog day!
My little blog is officially one year old today! :)
Over the last year I've made many more posts than I was originally planning to make and judging by the number of subscribers and variety of institutions and people who visit it's not entirely all rubbish, or so I like to tell myself.
Ongoing projects that will hopefully get completely or improved in the coming year are:
Thermal monitor - networking coming soon
More raytracing (of course) - linking PhysX to it (thanks to Timothy's post here for inspiration) to improve on my rather primitive bouncing balls.
SPH and Lattice methods for fluid simulation
Sorting algorithms - I haven't posted much on this lately but some decent results so far
Massive Data set processing.
Anything else that grabs my interest
Over the last year I've made many more posts than I was originally planning to make and judging by the number of subscribers and variety of institutions and people who visit it's not entirely all rubbish, or so I like to tell myself.
Ongoing projects that will hopefully get completely or improved in the coming year are:
Thermal monitor - networking coming soon
More raytracing (of course) - linking PhysX to it (thanks to Timothy's post here for inspiration) to improve on my rather primitive bouncing balls.
SPH and Lattice methods for fluid simulation
Sorting algorithms - I haven't posted much on this lately but some decent results so far
Massive Data set processing.
Anything else that grabs my interest
Tuesday, 21 July 2009
Throughput Computing
Two weeks ago I attended a seminar at the Daresbury laboratory near Warrington. Unfortunately I only had the day off so couldn't attend the workshops on offer and buttercup, my trusty landy, had to drive there and back on the same day. Sorry to everyone on the m4, m5 and m6 that day :p
Jack Dongarra presented a rather nice summary of supercomputing / parallel computing or as he called it "Throughput Computing". I had never heard this term before and now really like it. It implies that you should make the best of available resources in order to maximize throughput. It's very easy to get into a mindset where everything has to be in parallel but it's possible by doing so you neglect to notice that some parts work very well in serial.
Jack Dongarra presented a rather nice summary of supercomputing / parallel computing or as he called it "Throughput Computing". I had never heard this term before and now really like it. It implies that you should make the best of available resources in order to maximize throughput. It's very easy to get into a mindset where everything has to be in parallel but it's possible by doing so you neglect to notice that some parts work very well in serial.
Friday, 3 July 2009
Numerical Precision
Numerical precision is an ongoing concern of mine especially in big / long running simulations and solvers.
I came across an article by Rob Farber on the scientificcomputing.com site this morning that asks the question "How much is Enough?". Although no definitive answers are presented the author summarizes the current and future concerns over accuracy.
Personally I don't believe floating point is the way forward. Floating point is fast to calculate in hardware but is not always an ideal way of representing numbers. Although the various branches of mathematics are largely base independent humans are most comfortable with base 10 while computers are of course most comfortable with base 2. This does result in some situations when a calculation in base 10 with only a few decimals of precision gives precise results whereas a calculation in base 2 is incapable of giving a precise result even given N bits of precision although the result is probably acceptable after n bits.
I'm not presenting any solution to the precision problem, but merely pointing out that sometimes the issue is caused by: using base 2 for calculations and/or the floating point representation of these numbers.
I came across an article by Rob Farber on the scientificcomputing.com site this morning that asks the question "How much is Enough?". Although no definitive answers are presented the author summarizes the current and future concerns over accuracy.
Personally I don't believe floating point is the way forward. Floating point is fast to calculate in hardware but is not always an ideal way of representing numbers. Although the various branches of mathematics are largely base independent humans are most comfortable with base 10 while computers are of course most comfortable with base 2. This does result in some situations when a calculation in base 10 with only a few decimals of precision gives precise results whereas a calculation in base 2 is incapable of giving a precise result even given N bits of precision although the result is probably acceptable after n bits.
I'm not presenting any solution to the precision problem, but merely pointing out that sometimes the issue is caused by: using base 2 for calculations and/or the floating point representation of these numbers.
Wednesday, 1 July 2009
BV2 Thermal monitor v0.11
Here is a small update to the Thermal Monitor which implements the "always on top" feature. This can be enabled and disabled by right clicking on its little system try icon.
This is not the point release as planned as some of the additional features were appearing a bit unstable on my Win XP pro 64 machine. Until I find time to sort them out I thought I would release the most requested feature.
The source code is included. It is still in masm and does include routines for non-standard window shapes and transparent blts etc - could be worth a look if you are interested in masm32.
It is now available in the downloads section or here:
[download id="4"] - Please see Licenses Section for license details. By downloading you agree to be bound by the terms of the Creative Commons Attribution Share Alike license.
This is not the point release as planned as some of the additional features were appearing a bit unstable on my Win XP pro 64 machine. Until I find time to sort them out I thought I would release the most requested feature.
The source code is included. It is still in masm and does include routines for non-standard window shapes and transparent blts etc - could be worth a look if you are interested in masm32.
It is now available in the downloads section or here:
[download id="4"] - Please see Licenses Section for license details. By downloading you agree to be bound by the terms of the Creative Commons Attribution Share Alike license.
Thursday, 25 June 2009
Glass half full or half empty?
Or as this is a hpc/cuda/parallel processing site:
Gustafson's Law or Amdahl's law?
Personally I prefer Gustafson's Law .... it seems more logical to me or is this just because I'm inherently an optimist?
I would be quite interested on hearing your views on this - so comments /forum posts most welcome.
In other news: The thermal monitor downloads have gone over 80! :) The updated version (v0.2) is ready after mucking around with subclassing a control.... I will release it soon...
Otherwise I have been extremely busy on debugging a sparse matrix solver - bugs in huge datasets can be hard to find! Even with the aid of Gold / Sivler / Bronze kernels mentioned in the last post they have been proving remarkably tricky to isolate. Rather surprising to me is the fact that the long long data type doesn't consume a lot more processing time than a normal unsigned int - so I have been using that wherever there is a risk of exceeding 2^32.
CFD code coming soon too - although I have unwound a lot of the optimizations in order to make it easier to understand and possibly be a good foundation for your own optimizations.
Right .... back to the grindstone!
Gustafson's Law or Amdahl's law?
Personally I prefer Gustafson's Law .... it seems more logical to me or is this just because I'm inherently an optimist?
I would be quite interested on hearing your views on this - so comments /forum posts most welcome.
In other news: The thermal monitor downloads have gone over 80! :) The updated version (v0.2) is ready after mucking around with subclassing a control.... I will release it soon...
Otherwise I have been extremely busy on debugging a sparse matrix solver - bugs in huge datasets can be hard to find! Even with the aid of Gold / Sivler / Bronze kernels mentioned in the last post they have been proving remarkably tricky to isolate. Rather surprising to me is the fact that the long long data type doesn't consume a lot more processing time than a normal unsigned int - so I have been using that wherever there is a risk of exceeding 2^32.
CFD code coming soon too - although I have unwound a lot of the optimizations in order to make it easier to understand and possibly be a good foundation for your own optimizations.
Right .... back to the grindstone!
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