I'm not normally given to mischievious comments but I recall using Mathcad back in 1990 !
It's one of those situations you don't forget.
I'm a lazy b****r so I tend to get up late. This does at least avoid the rush-hour traffic nonsence.
On this occasion my Sales Director - I call him that since he was so - but I had joined the company to enable him to relinquish his other tasks ( to me ) to enable him to develop sales - called me on the phone at home to say he had this client with a problem.
It was a radar display. Trouble was it was 'wonky' ! He barely uttered the words before I said it needed S-correction. There was a mutter. He said "no they thought of that". I thought otherwise.
Simple high school physics equations showed me to be correct. Mathcad showed the result on a simulated screen. It matched.
We got the project to fix it. We fixed it. They even wanted more ! I don't even want to go into how their engineer had arranged the AGC for the radar receiver !
Some time ago terry harris posted his neat little program Rescad.exe, that finds pairs either paralleled or in series together with the deviation etc. Only 150k, I have it here on my desktop. I searched and it seems no more available, but if anyone drops me a mail ...
I have been using Mathcad since 1992, and matlab since 1990. I do the bulk of my work in MathCAD, basically because it can be fully self-documenting, as mentioned by others. Like any package, the user interface is a pig when you are unfamiliar with it, but its dead easy with practice (equation editing can be explained in about 2 minutes). Mathcad has IME always had one *major* problem - it crashes. And there is no auto-save function. I havent used anything past Mathcad2000, nor do I intend to. symbolic calculations, large datasets, tricky graphs etc. can be a problem.
For real computing I use matlab. Expensive, but worth it. it allows serious brute force to solve problems eg series/parallel resistor value optimisation - done by calculating every possible combination using list of available (IOW production) parts, then sorting in order of best fit for each of 4 different topologies. Sure, it takes a few hundred million calculations, but thats only a few seconds after hitting enter.
matlab has seriously cool tollboxes too. FEMLAB looks promising (although the version I tried kept eating RAM, and wouldnt mesh the halbach array) for multi-physics FEA too.
smt engineering often involves minimising the number of different bits.
beware of the often seriously screwy distribution of resistors etc - anything that is tested and binned according to actual value will, of course, have holes in the middle of the distribution. expect a +/- 1% hole in the center of your +/- 5% distribution. likewise a hole in the middle of the 1%.....depends entirely on the product mfg process of course.
another thing to look at is tempco. a -20 to +80C swing across a 200ppm part is a 2% change.
by the time you factor in placement cost (often as much as the smt part itself), the differential price between 1% 50ppm and 5% parts is bugger all, and is insignificant unless the production volumes are staggeringly high.
For precision work, it's too bad it rounds off input numbers to 3 digits.
Best regards, Spehro Pefhany
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every part? mighty impressive process. A better way of phrasing my statement would be: never assume a distribution is any shape until you have verified it.....
big ones, PRC201's etc.
so if its done by laser trimming, the only difference is the process time, hence small differential price.
absolutely. and all the other factors. Vishay & philips (or whatever they morphed into) resistor datasheets are quite an eye-opener for the un-initiated.
You can get the student version of MATLAB for much cheaper. That's the way to start and see if you think the big step to pro version is justified. The student version is not matrix size limited and comes with a scaled back version of the Maple symbolic engine too.
I don't think there is any question that MATLAB has come to dominate the engineering applications facet of math software packages, and I don't see that changing anytime soon. Its numeric engine is superior to any of the others. You can run massive amounts of data quickly if you do the so-called "vectorization" of your code (don't worry about that at first). The first time a function file is run in MATLAB, it is /interpreted/. But that first run /compiles/ it into RAM, so subsequent runs are essentially compiled code rather than interpreted code. It is very fast. Of course, you can spend the money and get the outright MATLAB compiler too, but most folks don't need to produce standalone executables.
MATLAB may have become popular because the learning curve is not steep (I don't agree with Mark), especially when it comes to programming and quickly producing a high quality graph. Free help is better on comp.soft-sys.matlab (IIRC) than for any of the others.
I still use Mathematica a tiny bit -- mostly for solving fairly simple simultaneous equations symbolically. You can do that with the Maple engine attached to MATLAB too, but I actually prefer Mathematica for symbolic operations, even though I have the pro Maple symbolic engine attached to MATLAB. Incidentally, the symbolic engine of Mathcad is the Maple engine too. To my knowledge, Mathematica and Maple are the only two symbolic engines of any importance.
My opinion is that plotting/graphing is best with MATLAB, over any of the other packages. It's so-called /Handle Graphics/ are very powerful and make sense, although it takes some time to figure out (Patrick Marchand's texts are almost better than the MATLAB documentation).
I think the learning curve for Mathematica is steep. I don't even have Mathcad installed anymore. Despite the criticisms of Mathcad, I don't think it is so bad when one considers the price and what it is actually designed to do. Furthermore, Mathcad really doesn't try to compete with MATLAB -- it is a different beast. I view Mathcad as more of a high powered calculator scratch-sheet or spread-sheet, than a programming language. But one can do some programming with it, but not really like MATLAB, Mathematica, or Maple (especially MATLAB). MATLAB, Mathematica, and Maple are fundamentally high level programming languages. Mathcad isn't, so we should not expect as much out of it in that way.
The problem with all of these is that they are proprietary. I think there are some free pseudo-clones for MATLAB. But the m-files (function code) would need at least some touch-up to run in these other packages. I don't think many people use IDL (interactive data language,
formatting link
but it does work.
MATLAB is certainly king for now, and likely will stay that way for a good time, for whatever that may mean to you.
Of course, MATLAB, Maple, and Mathematica are programming too, but made much friendlier for the engineer and other users.
MATLAB is to hardware/system/DSP engineers as C/C++ is to software engineers. It is not a substitute for Spice, although you can take Spice output and make wonderful multi-dimensional graphs not possible in Spice. (I've noticed the graphic output in an increasing number of professional papers and texts are produced with MATLAB).
I was looking at a qualified lower division engineering programming class at a local college. The class was not Fortran, like I had to take. Nor was it C/C++. It was MATLAB!
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