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Jason

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(no subject) [Dec. 19th, 2016|08:38 pm]
Jason
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Went through the projects of "nand2tetris part 1" in a few hours over last evening and this. Very cute to cobble together a little cpu from nand gates. I guess I never appreciated the various relationships between other architectural choices and the choice of having a control FSM in a cpu versus not --- notably the nand2tetris cpu is single-cycle, and gets away with it because it's Harvard architecture (program lives in a different memory from data) so it can simultaneously read from program memory and data memory in a single cycle without any problem. The j1 gets away with being single cycle despite being von-Neumann by simply demanding a two-read-port RAM. So then under most other circumstances, you probably want multiple cycles to execute instructions; maybe you want cycle times to be as short as possible by chopping things up into pipeline stages, maybe you just want to squeeze instruction fetch and memory reads into the same RAM port.

Dunno, I bet all of this stuff is college-freshman-obvious to ECE folks, but it's neat to see it with fresh eyes coming from much higher up the abstraction ladder.
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(no subject) [Dec. 18th, 2016|10:30 pm]
Jason
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Today was warm until it wasn't; the evening, during which I went and picked up my laundry, showing signs of being legitimately Winter again.

Took the leftover ingredients (sauce, cheese, sausage, also some unused spinach) from pizzamaking and turned them into a pasta bake. Also v tasty.
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(no subject) [Dec. 17th, 2016|10:24 pm]
Jason
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Made some from-scratch pizza again for dinner. Dough turned out slightly crackery in flavor, but I got a lot of good rise out of my yeast this time. I have a space heater in my little office, and I just kept it near that for a couple hours, and that seemed to work great. For flavor, I figure I probably need to have more fat in it, or else give up and use something playing the role of pizza stone instead of just tossing it in the oven and hoping for the best. Toppings included some sweet italian sausage, which worked really well.
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(no subject) [Dec. 16th, 2016|08:11 pm]
Jason
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After getting home from work immediately appeared to be a traintastrophe in the making, went to see Esther Schor talk about her book "Bridge of Words". Kinda neat. The stalled train situation had resolved itself in the meantime, got home, had some ramen with K.
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(no subject) [Dec. 15th, 2016|06:14 pm]
Jason
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Made some bread to make sure my yeast supply is still alive, in preparation for planning to make some pizza tomorrow. It is, and bread turned out fine. Ate it straight out of the oven with butter and honey.
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(no subject) [Dec. 14th, 2016|06:12 pm]
Jason
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Thai curry leftovers for dinner. Got a copy of Hennessy and Patterson's textbook on Architecture, and I am enjoying catching up on all the low-level processor/memory hierarchy/etc. stuff I usually ignore as a theorist.
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(no subject) [Dec. 13th, 2016|09:36 pm]
Jason
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Something that's bugged me for a long time is this:

How many paths, starting at the origin, taking N steps either up, down, left or right, end up at a particular place (x, y)? Ignoring the fact that x+y has to have the same parity as N, something that goes like e- k(x2 + y2), right? Just central-limit-type reasoning ought to suffice to see that. It's a nice plain isotropic Gaussian sitting at the origin... so there are about as many paths to (x, y) as there are to (x, y) rotated by some smallish angle θ, yeah? Doesn't this mean there ought to be a combinatorial function --- or, like, "approximate" function or something that "rotates" paths by angles less than 90o, even though the paths themselves are made of chunky up/down/left/right steps?

And yet I can't for the life of me hack up anything that seems to work. Somewhat annoying.

I tried staring at the fact that surely you can pretend |N>, |E>, |W>, |S> are states in a Hilbert space, and take the discrete rotation |N> → |E> → |S> → |W> → |N> and make a continous version of it by saying

|N> → f(t)|N> + f(t-1)|E> + f(t-2)|S> + f(t-3)|W>
where
f(t) = (1+eπit/2+eπit+e-πit/2)/4

but this doesn't seem to do anything nice when I make a big tensor product and ask what happens when some typical state, like, |NENSENSNWNWNWWE> gets rotated; there doesn't seem to be any tendency of the norm of its displacement to get preserved, even in expectation.
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(no subject) [Dec. 12th, 2016|09:21 pm]
Jason
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K made some very nice thai chicken curry for dinner; didn't accomplish much myself. Trying to read through the RISC-V Rocket implementation to see if I can understand much. Conclusion so far is "not really".
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(no subject) [Dec. 11th, 2016|06:47 pm]
Jason
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Still watching "Hell on Wheels". The characters motivations frequently make no sense at all, but at least they killed off the by-far most annoying character in the show.
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(no subject) [Dec. 10th, 2016|08:59 pm]
Jason
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Cold weather, so: made some cookies. This time snickerdoodles. The cinnamon does, it seems, come across better when it's on the outside rather than in the dough, even at the same quantity. I do still kind of like black pepper as a cookie spice, but I left it out this time around. I find it a bit tough to gauge how much water I need to add after the egg, which seems to depend on ambient weather. Sometimes the egg is enough, sometimes a good bit of extra moisture is needed, and the transition from "this is totally unworkably dry" to "holy shit need more flour to stop it sticking to my hands" is really abrupt. Possibly compounded by the butter gradually starting to go soft the whole time. Shrug, baking. They turned out pretty decent this time, anyway.
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