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Comment by tmostak | Hacker News Reader

Hi all, MapD creator here - I'd be happy to answer any questions. The 700K figure was done by rendering polygon files to textures and using them as lookup tables - it ran pretty fast on the CPU so its not all the GPU there. However if a point falls on a border - perhaps 1% of cases for say a medium-sized raster of the US - you have to do a geometric lookup as usual - which I didn't benchmark. Probably better would be to do some tiled implementation - basically something like textured quad-trees.

And as I told the journalist I wasn't sure if I did the PostGIS indexing right - I feel like the quote got taken a little out of context - but the speedups were "high" to "quite high" regardless.

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> By opening the code, Mostak opens up the possibility of having a competitor rapidly develop a system and force him to the edge of the market. That possibility doesn’t bother him, he said. “If worse comes to worst, and somebody steals the idea, or nobody likes it, then I have a million other things I want to do too, in my head,” Mostak said. “I don’t think you can be scared. Life is too short.

Can I just compliment you on your attitude?

Heh ... when I saw the speedup numbers, the first thing I wondered was ... index? Regardless, this is impressive work. Do you have a tech report you can point to for someone to get more details? I'd love to learn more about your setup. Also, would you mind describing your programming background? I have a cs PhD and I admit I never had the guts to get into GPUs! You've given me a whole lot of motivation!

Thanks! Yeah I'd like to revisit this benchmark soon (I'm actually working on rendering choropleths on the GPU now). I'm working on a database paper that will hopefully be ready for VLDB submission by next month - that would probably be the best.

In terms of CS background - nothing formal except for AP comp sci I took in high school like 12 years ago. However I've always loved hacking on things on the side, and a combination of my research on the Middle East/burning desire to make an Iphone app kind of got me back into it. Then to be fair I took a GPU Graphics class (basically OpenGL) at Harvard and then a Database course at MIT while doing my Masters in ME Studies, which is where this project started.

Can you tell me whether the main reason for speedup is because of using GPU, or do other factors also play in (such as new algorithms)?

This seems really interesting as a concept, and much more so as a working product!

Is MapD written to any specific GPU language, like CUDA or OpenCL? I'm in the market for new GPU and this might be a factor in purchasing... ;)

Also, I can sympathize to the mismatch of creation vs running business.

Thanks for the clarification! I was highly suspicious of the 700k figure, it makes a lot more sense with the context of precomputing and then looking up.

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