yup. deeply regret my time as a postdoc. especially the last few years in the pandemic have been the absolute worst work experience in terms of culture and job satisfaction. it's killed the passion for research i had at the start.
the worst part is that i think this experience has completely tanked my confidence.
"The way I read papers is by first reading the abstract. Then I try to state the results and prove them myself. When I get stuck I go to the paper to see what I got wrong."
This is like some advice I figured out from experience about software courses.
Don’t do the course until you have tried doing the thing without the course first and hit the pain points.
Then, when attending the course your brain is in a different mode. You are filling the gaps rather than laying the foundations. And you get much better value out of it.
(This is for in person courses where you can ask questions - so the value you get out of it might be how good your questions are)
> Do people think that algebraic geometry might be thought of as the root of all geometry?
I certainly don't think of it this way.
There are many geometries and spaces that cannot be described fruitfully within the framework of algebraic geometry, much the same as how there are many functions that are not analytic.
There are ways (called heuristics) to solve some NP hard problems faster than exhaustive search.
Of course, for theoretical reasons, a heuristic is not guaranteed to be faster on all problem instances.
The general idea is to do some engineering and find a heuristic that works well for your problem. More sophisticated algorithms will try multiple heuristics at the same time (I believe OR tools has options that falll in this category). There is even research by now that aims to use ML to find good heuristics for a given family of problems (where the common characteristics of the problems might lend to a dominant heuristic).
These heuristics can still have guarantees of correctness. A good place to start is by looking up "branch and bound" algorithms, e.g., for ILP problems. The idea there is to narrow the search space while maintaining some theoretical guarantees.
(Not an expert but i did a project on this once. I'm sure someone more expert can come along and correct where I'm wrong.)
> There is even research by now that aims to use ML to find good heuristics for a given family of problems (where the common characteristics of the problems might lend to a dominant heuristic).
I think I have spotted some papers about this for combinatorial problems but not for continuous variables, which makes sense given their relative hardness.
Do you know some papers, journals, conferences about this?
I'm interested specially about the view from people working in optimization research more than in AI.
I think we're probably thinking of the same papers. There was a competition /session at last year's neurips and there's related papers linked from their webpage.
At that point you need to put your heat exchanger pipes underground, which is more annoying than air-based AC but not insurmountable. The temperature 20 feet underground will be about 50 F year-round. Of course, if a city of millions tried to do this all at once I have no idea how the local ground temperature would react.
> 20 feet underground will be about 50 F year-round
Is that the case in India? I was under the impression that while underground temperature is consistent across seasons, it does vary considerably across climates, with warmer climates generally having higher underground temperatures. For example, while much of the central US has underground temperatures around 50F, southern Florida, California and Arizona have areas with temperatures in the upper-70s[1].
I can believe the ground temperature is higher nearer to the equator. At the same time, you don't need the ground temperature to be very low, just low enough for the heat exchanger to function. Alternatively, you can dig deeper until you hit a lower temperature.
As someone who was in Europe for one of the heatwaves of recent years, and whose appartment was in one of these older buildings designed this ways with thick walls etc., I can attest that this only works up to a point. This design relies on there being cold air for the building to retain. However, in a heatwave it doesn't even get cold at night. The result is your apartment gradually heating over a period of days / weeks and turning into a sauna. It is not pleasant.
By the end of that summer I was dreaming about moving back to north america where air conditioning is much more common in rental units.
What Europe needs is heat pumps and lots of them. More efficient heating, simply run them in reverse during a heat wave for refrigeration.
Most of the Continent is mild enough in winter that an air-loop heat pump will reliably heat throughout the winter, and these aren't more expensive to install than other heating systems, they're less energetically intense to operate, and they provide cooling on demand.
Problem with that is electricity is expensive in Europe. Of course as you know Europe varies a lot between Portugal and Romania. While the first has a balmy 10C in winter daily low, colder areas can easily have -10C, -15C at night. That's the minimum operating range of a heat pump.
That's a 30C difference to work through. That's why they have cheap (Russian) gas, it has the biggest energy density (and nuclear).
Ground-source heat pumps would work better in continental Europe but they are expensive to install (I have only seen them in new build villas).
Putting the gas into electric generators and using that electricity to heat is more economical than burning it in a furnace for heat, heat pumps are just that much better.
I agree that the national programme must be more detailed than just declaiming "heat pumps!" and calling it even.
I gestured vaguely at the existence of parts of Europe where cheap mini-splits might not be sufficient, let's just agree I'm talking about the places where they will be.
Apologies if my comment made it seem I disagree with you.
Air-source heat pumps can definitely be used in many countries here, in fact they are already popular in the UK, and gaining popularity in Spain, due to their efficiency.
Yeah it's a temporary effect and once the walls have heated up, it actually makes it worse since it retains the heat at nighttime as well.
You need to drill down to access the constant temperature in the ground, to be able to really counterbalance the differences in the air temperature. Once you've drilled down I guess you can make a passive or minimal energy circulation system that would be much more energy efficient than air conditioning.
It’s called a geothermal heat pump and they’re quite efficient in the places they can work (which is basically anywhere that has enough temperature differential during the year).
I had an issue with this last fall - had my AC go out in the fall when it had been over 80F for the last few months. Outside, it would be 70 during the day and 50 overnight, but there was so much heat in my walls/floors that I literally couldn't keep my apartment below 80. If I opened every window and door, I'd get down to 75 or so, but it would be back to 80 within an hour, even when the temperature outside was significantly cooler.
It's great in the winter though. I haven't had to turn my heat on in years.
Northern Europe complains of the heat in the summer - they have nice radiators for the 7-9 months that need heating, Southern Europe complains of the winter cold because of the lack of insulation and central heating.
That’s so weird to me - why on earth would you skimp ion insulation? The stuff barely costs anything and it helps keep the place cool in the summer as well as warm in the winter
Staying indoor in 24C air-conditioned spaces conditions the body so badly that even 28C starts to feel bad. I noticed this in my own behaviour and thought of changing it last month. For a change, I decided to drive without air conditioning. It felt bad for a few minutes, then it gets better and when I come back to a cooler place it feels like heaven.
Exposing yourself to the elements is greatly rewarding.
That's actually true. I had a car with A/C in southern europe which I traded in for one that doesn't have one (don't ask how). The first month was brutal but this year it's been already 30C+ and I don't even feel it.
30c in Castilles and Madrid is nothing.
Siesta for that it's ridiculous. No one does that. What we do it's to have lunch.
Siesta it's for days bordering 40 and up.
Also, beware of the stereotypes. You will freeze up in 3/4 of Spain if you dare to get out in shorts and flipflops on Winter as many tourists do.
> Despite all that, what I’m hoping for is that someone will come along and tell me that I got it all wrong. “When you do it as follows, the system works: $explanation” Because, you know, I’d really like to have static typing in Python.
I want X. Y (which is designed for somthing other than X) doesn't do X. Thus, I don't like Y.
FWIW I lead with this whenever I find myself teaching lin.agl. and I agree it's the most important point of context for students entering the subject (and presumably embarking on undergrad math).
Yeah, it’s funny how most of high school is spent focusing on the “exceptional” solvable cases of nonlinear equations (low degree polynomials, simple trig equations, exponentials) that one can come out with the skewed idea that solvability in nonlinear equations is more common than it actually is. While I understand that it’s important to build up a vocabulary of basic functions (along with confidence manipulating them) I think it is also important to temper expectations with the reality that nonlinear behaviors are so diverse and common that it is an a small miracle that we have somehow discovered enough examples of analytically solvable systems to enable us to understand a rich subset of behaviors!
the worst part is that i think this experience has completely tanked my confidence.
now id take a jr python dev job in a second.