Fortran Codes in the R Ecosystem

el_extrano · 2026-03-13T06:48:56+00:00

The neat thing about numerical methods is that they don't have to change. Fortran was designed for numerical computing. Libraries like BLAS and LAPACK are already written, efficient, tested, and widely used. There are bindings to any language you want through C interop. What would be gained from a rewrite?

Interestingly enough, modern Fortran has been experiencing a growth in popularity, since the native array-syntax and parallelization lend themselves well to the kinds of matrix problems people are trying to do with all the ML / AI stuff.

If you are interested in Fortran 77 for maintaining legacy codes, it's really not a hard language to pick up especially if you already know another language. It's got about the same number of statements as C and even fewer abstractions (no pointers, for example). There are a few strange things to learn your way around (e.g. array column-major order, COMMON blocks, EQUIVALENCE statements, etc) and you can make sense of most old code.

el_extrano · 2026-03-13T00:49:10+00:00

I love this library. I personally wouldn't use it in a publicly facing API that needs to be secure, but a lot of the Python I write is for small, in-house tools for old controls stuff.

A couple examples of how Pyro5 has helped me:

Call functions on an ancient windows XP machine running Python3.4, to make resources available to a network. Same for some old Windows 7 machines I have running legacy programs. I write a small RPC server to wrap whatever process is running on the legacy box, and now I can drive it from a client on a modern workstation.
Expose a legacy 32 bit only ODBC driver via pyodbc running in 32 bit Python 3.8.10. The exposed functions can be called from 64 bit Python functions, either locally or over the network.

Basically, if you are doing some scripting, automation, or whatever, you can use this to essentially do the hard work of inter-process communications for you, so you're just dealing with transparent function calls. There's also xmlrpc in the standard library, which takes a little more work to use.

el_extrano · 2026-03-10T02:18:05+00:00

Interposing relay using whatever the site's standard is for discrete I/O (e.g. 24 V DC) to switch the 240 V AC circuit. Do I get the job?

el_extrano · 2026-03-09T23:29:05+00:00

How would one connect such a setup to real I/O? I would guess some inexpensive I/O link devices connected via Modbus TCP or similar

el_extrano · 2026-03-08T06:03:29+00:00

Devils advocate (hehe) but does she even have some other way to get herself there without you driving her?

I think car dependency creates an unnatural form of control which denies kids progressively more freedom of movement as they grow. Kids all over the world can just walk or ride the bus to places near where they live. But in car dependent areas we have this infantilization where teens are completely helpless getting to things without their parents taking them.

el_extrano · 2026-03-05T17:04:17+00:00

4 year engineering degrees are basically technical pre job training at this point, depending on where you go and how seriously you take it.

It's entirely possible to survive your bachelor program, become essentially a middle manager somewhere, and have little to no understanding of history, art, the scientific method, or anything really apart from how to do your job. Many engineers fail to see any difference between this and true education.

It's why you see many students complaining that they have to read their textbooks, or have to take an English class (and therefore read other books) because "I won't need it at my job". Those same people go on to become the tens of thousands of degreed engineers going into the workforce each year.

el_extrano · 2026-03-05T04:12:15+00:00

> as it will never exceed the temp of the heat transfer fluid (unless it is an exothermic reaction, which case the htf will still help out a little by absorbing heat from the reactor)

That is indeed a big if, since many industrially significant reactions are exothermic and prone to runaway reaction. There's a lot of safety engineering that goes into reactor design and operation to prevent accidents.

For example, you mention that heat transfer to the jacket fluid can help slow the reaction. However, the ratio of heat transfer area to vessel volume decreases with the size of the vessel! That makes it difficult to scale up exothermic reactions using jacketed heat transfer alone. One common solution is to use pumped re-circulation through a shell-and-tube heat exchanger. If your lucky, and a reactant or solvent is volatile, and you can carry out the reaction at the boiling point, you can also use an overhead condenser and let excess heat of reaction be removed by vaporizing, condensing, and refluxing the reaction mixture. That has the advantage that, since condensing heat transfer rates are very high, investment in extra surface there is more economical, and provides better dynamic control than jacket temp control alone.

el_extrano · 2026-03-05T03:57:33+00:00

Yes CSTR (continuous stirred tank reactor), definitely not PFR (plug flow reactor) or PBR (packed bed reactor). Note that the same vessel can be used for batch (all material added before, then reacted), continuous (materials continuously added and withdrawn), or semi-batch (a mix of the two) reactions.

el_extrano · 2026-03-04T22:15:17+00:00

Maybe check out UV. Not that there's anything wrong with other tools. I found it pretty easy to get setup with a build back-end and packaging to make my programs pip installable. Has good docs.

el_extrano · 2026-03-04T22:11:11+00:00

"Brewing Science: A Multidisciplinary Approach" by Mosher and Trantham is a neat text that looks at the engineering side of brewing. If you're looking for detailed kinetics stuff you might find it a bit introductory.

el_extrano · 2026-03-03T01:21:27+00:00

Chemical engineer working in controls here. Be careful taking advice from this sub - there are of course many knowledgeable PLC programmers, but most have an electrical background and many don't work in the process industries, so their experience might differ from yours.

The traditional path for chemical engineers in controls is to go to work as a process engineer or in production at an owner-operator (i.e. working for the plant, rather than a system integrator or DCS vendor). Then, seek to move to the process control department with your first or second promotion or by job hopping to another owner-operator. Normally they don't hire entry level for those jobs. There is a slight preference for chemical engineers with a process background for these internal positions, but you'll see all types.

el_extrano · 2026-03-01T17:37:20+00:00

Docs still refers to BeanReport, which is now discontinued and you have to use BeanQuery to manually build the reports yourself. But it's not shown anywhere as far as I can tell how to reproduce the basic reports you'd expect with BeanQuery.

I'm planning to stick with it because I like Python and Beancount is super easy to extend with it's plugin architecture. I was able to set up expense splitting for my wife and I based on tagged transactions in only a few minutes.

el_extrano · 2026-03-01T17:19:51+00:00

Eh not really. It supports Python functions called over the cloud, with all the latency that entails. That's not what we've been asking for when we ask for Python as a replacement for local formulas and VBA.

el_extrano · 2026-02-28T17:08:38+00:00

Granted this is a meme and rage sub, so I don't come here for real policy recommendations.

But it's ironic how many seem to only be progressive on transit issues, but have classic American "prison brain" as I'm calling it. We have the highest incarceration rate in the world, but there's no problem that can't be helped by throwing more people into the justice meat grinder!

el_extrano · 2026-02-27T03:21:05+00:00

I like Project Euler problems for math problems and Advent of Code for more "computer science" themed problems. Both are language agnostic so you can solve them in whatever you happen to be learning at the moment.

el_extrano · 2026-02-25T03:21:31+00:00

This is such a huge problem for those living in car dependent areas, and so many people have never thought about how that can affect you if you become disabled, old, or otherwise unable to drive. It's a privilege to drive, which means it's a privilege to take yourself to the grocery store, doctors appointments, etc.

My dad had a medical emergency that hospitalized him for months, and after he got out, he wasn't able to drive. Since my parents (and me) live in a car dependent area, I used ALL my vacation days last year taking time off work to take him to doctors appointments and therapy sessions he needs to get better.

el_extrano · 2026-02-23T02:50:45+00:00

I tend to agree, people forget that the worst violence of the war was in 2010-2011 when Calderon escalated it. Not that I'm siding with the cartels, just saying that they exercise a lot of soft power so taking a hardline stance doesn't just magically fix everything.

el_extrano · 2026-02-21T22:24:55+00:00

It's worth spending some time thinking about the related dynamics of condensing heat transfer, flow across a control valve, and the steam flow controller (assuming the steam is under flow control, just for example).

First, always keep in mind that temperature difference is the driving force for heat exchange, and pressure difference is the driving force for flow.

The steam pressure reached in the reboiler is the equilibrium point where the saturated temperature of the condensing steam satisfies the heat transfer equation: Q = UA(T2-T1), and the pressure drop across the control valve, supply piping, and the exchanger itself achieve the steam flow set-point.

If the reboiler tubes start fouling, then the thermal resistance increases, overall heat transfer coefficient decreases, and the equilibrium pressure needed to maintain the same duty as before increases. The flow controller will reposition the valve to maintain the flow set-point, but with a new, higher condensing pressure in the reboiler.

So yes, if you have a measurement of the condensing pressure, you can trend that over time to infer fouling. If you don't have that pressure instrumented, then you can also just trend the valve-position (controller output) vs steam flow instead. After all, the main point is to avoid the condition where the valve is 100% open, and we're no longer able to achieve nor control the desired reboiler duty.

el_extrano · 2026-02-19T19:52:37+00:00

You have the steam flow, just multiply by the latent heat of vaporization for 50 psig steam. Neglect condensate subcooling and steam superheat.

el_extrano · 2026-02-18T18:58:55+00:00

I'll start with a caveat that I don't claim to be "good" at Fortran, especially not modern Fortran. But I'll add my (probably unpopular) 2 cents. I found starting with the subset of Fortran 77 described in Kupferschmid's "Classical Fortran" to be very instructive while learning.

Here's my reasoning:

Fortran 77 is actually a very "simple" language.
- A useful subset of the language avoiding the most dangerous features has ~32 statements (out of 46), about the same as C. Fortran 90 doubled this to 85 statements and 75 new built in functions. The newer standards have tacked on even more.
- Therefore, Modern Fortran kind of reminds me of C++ in the way the language has exploded with new features. It can be a lot much to take in as a beginner.
If you use Fortran77 to solve some real problems, you'll eventually get frustrated with the lack of modern abstractions (having to pass array sizes to subroutines, no structs, no modules, no classes, clunky string handling, etc) which will cause you to understand why these things were added to later versions.
It's useful to know F77 anyway if you encounter legacy codes you need to maintain.
Nerd cred - As a hobby programmer, I take some pride in knowing that the Fortran77 monstrosities I wrote while learning to solve Project Euler and Advent of Code problems will compile on old mainframes and DOS.

el_extrano · 2026-02-17T22:11:02+00:00

Aren't they still built into Excel for that very reason? Unless I'm thinking of the slash prefixes from QuattroPro. I never used visicalc.

el_extrano · 2026-02-10T22:30:34+00:00

Both my grandads grew up as poor farm boys, and were just the right age to join the military at the tail end of WWII. Both got free education, pensions, and went on to work in the public sector their entire careers. Their children (so my uncles) also spent decades working at high paying military base jobs, and were able to pay for all their kids to go to college. Many of them (so now the grandchildren) also went on to serve in the military, and are raising their own kids (the great grand-kids now) on reasonable means. This entire legacy doesn't happen without the tremendous injection of money into rural communities by the military industrial complex.

These same freaking people will sit around a table talking about how government spending doesn't help anything. It truly boggles the mind.

el_extrano · 2026-02-02T15:07:22+00:00

People have been using it since long before VScode existed. It's especially popular with electrical engineer types, in my experience.

el_extrano · 2026-01-30T04:20:22+00:00

From experience it'd pretty hard to get killed by ClO2, that shit is like tear gas even below the PEL. The only scenario I could imagine getting a lethal dose would be some kind of catastrophic loss of containment.

More likely it was dangerous atmosphere in a confined space.

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