Re: Too much time on their hands!

there is ...

why is it so hard to imagine that you want to do something with speed and accuracy, weight and feel can make a difference?

I still remember the good old days (early 80's) when the Swiss firm Logitech started out by marketing the ETH Zurich Modula2 compiler and bespoke word processing software. "Logiciel" being software in French. (French language police would not allow the nasty English word)

Long before they started making any hardware. The mouse was an unexpected consumer success when Windows took the world by storm!

You need to eat more shredded wheat!

Gaming machines can be decent general purpose machines if you delete the graphics card entirely. Doing that prevents you from running most AI codes and various gofaster GPU based parallel processing libraries.

Unless you do a lot of video editing or 3D rendering the GPU built into the modern Intel chips is entirely adequate for 2D business graphics.

I'm hardly a body builder, but the boxes have nothing to grab, and have doors and filters that slide around. One has to rig them with ropes or straps to move them around. Sitting on a carpeted floor, they may as well be welded down.

I wish they would help with Spice. Yesterday we were running a pretty simple power supply sim at around 100 us/s. It takes many minutes to settle out, and it's hard to learn with such delayed feedback.

Have you tried running two instances of Spice at the same time?

On a suitably beefy machine with plenty of ram it might be possible to run two different sets of parameters at the same time on the performance cores without saturating memory or disk IO bandwidth.

It will depend critically on how big the matrix problem gets but for some smaller problems it might possibly be an option.

Two instances would be confusing. One use of Spice is to train one's instincts and iterate a design.

At times yesterday, the power supply sim was running at picoseconds per second. LT Spice allows one to set the max time step, but not the minimum time step.

The Gear solver and some relaxed tolerances seem to be better for this case.

In one recent case the sim kept stalling. I added a 1K resistor off to the side, one end grounded and the other end connected to nothing. That fixed things.

Inductors, especially coupled inductors, are quirky. A little ESR often helps, but that may be random, like the 1K resistor.

I wonder if just moving parts around the screen affects the sim. Gotta try that.

I think LT Spice was once called Switchercad. But it's terrible with switchers.

ok, if you say so ...

obviously. as always for every answer you get you add five new reasons why it wasn't the answer you were looking for

no, it is games played with a mouse

playing a game is not signing you name

it is games played with a mouse.

You could try two alternative values for one parameter at the same time.

That is usually an indication that there is something stiff about the differential equations being solved and that the algorithm has halved the time step many times in a desperate attempt to control the error budget. I once had a plot job from solving a very stiff set of equations cancelled by the operator "because the red pen began to work loose". The line segments approaching zero got very very short indeed!

That is odd. I can imagine adding a 1M resistor between some pair of nodes might take the edge off it.

Resonant tank circuits with high Q can sometimes cause trouble.

Trying to solve the matrix equations ( i.e. calculating the nodal voltages from the G-Matrix and the current vector ) may result in divide-by-0 errors when a node has absolutely no conductivity to other nodes. Therefore, some artificial conductivity is introduced. Otherwise you could not solve a circuit with 2 capacitors in series and nothing else. The art is to choose the conductivity so that the equation system can be solved without div by 0, without changing the original circuit too much. Different spices may handle that differently; usually there is an option to set the minimum conductivity to GND if the automatic choice does not work. There is no such thing in spice like a node that floats in nirvana.

AFAIR there is also a limit variable for g-matrix elements that are considered for pivoting during solution of the equation system.

Last time I looked deeper into this was when I tried to compile Spice 2G6 or so on my new 10 MHz 286 with 70 MB disk under Interactive Unix. Oh, those 64k segments! Fortran memory management was done by indexing out of the bounds of a small array. =:-()

That a student had a 70 MB disk all for himself was quite close to hubris. The institute VAX had 2 * 300 MB Fujitsu Eagle with one disk for us mortals.

Gerhard

Adding the dummy resistor, or maybe moving parts on the screen, probably changes the martix hence the order that things are done in. It is a strongly chaotic system, at least for non-trivial circuits.

Sometimes changing a resistor from 50 to 51r will fix a stall too.

The LT Spice initial conditions solution can take ages too. Best to skip it.

I had a DEC RSTS timeshare system with a 64 K word fixed-head hard drive as the swapping disk. Fortunately it failed pretty soon.

The old ECA circuit simulator was cool. You specified the time step, and once in a while it might say "divide by zero error" and just keep going.

why play baseball with a bat?

The computer mouse is like a real mouse. It has been optimized by mutation and natural selection.

I was talking to some neighbors that we met hiking on a stairway (we have lots of stairways around here) about how bad it is for ones body to sit in front of a computer most of the day. We decided that we need a Peloton Mouse, really heavy with buttons that are very hard to push.

The pressures of natural selection in this context might be maximum profit because it looks nice, not user convenience.

Users don't select products based on the suppliers profits.

I buy a fabulously expensive ($19) Dell laser mouse.

Suppliers profits depend on users selecting their products. Most people select on what looks nice - by the time they discover it gives them repetitive strain injury it is too late to change it and the supplier has pocket the profit. ...So they chuck it away and buy a different model of the same make because it looks nice ...and so on.