Re: What's the best language to start with? [was: Re: Should I learn C or Pascal?]

["Tim Behrendsen" <tim@airshields.com>]

Craig Franck <clfranck@worldnet.att.net> wrote in article
<50sj6q$aci@mtinsc01-mgt.ops.worldnet.att.net>...
> "Tim Behrendsen" <tim@airshields.com> wrote:
> >Bob Cousins <bob@lintilla.demon.co.uk> wrote in article
> ><322f864d.42836625@news.demon.co.uk>...
> 
> 
> >> Finally, you or may not consider that the human brain is a biological
> >> computer, and that does not appear to work by fetching instructions
> >> and executing them. So the very concept of instructions executing in
> >> sequence is an illusion created within our own non-digital,
> >> non-sequential, massively parallel active memory analog computer.
> >
> >The human brain works (as far as anyone knows) by electrical patterns
> >flowing through neurons.  You have input from your senses which
> >stimulates pathways in your brain, and produces changes in the
> >memory structures, and possibly produces output through muscular
> >manipulations.
> 
> Yes, but the *order* of the instructions might be an illusion.
> 
> 
>                      *
>              ()               *
>             earth   star A  star B
> 
> Say star A is 50 light years from Earth and star B is 100 light
> years away. If A went super nova 50 years ago and B went super nova
> 100 years ago they appear to explode at the same time. Without 
> advanced astronomical knowledge you would have no idea of the
> real order in which they exploded.
> 
> If I run a program to sum a matrix of 100 numbers on a computer
> with multiple execution units and several concurrent tasks, I
> may have no clue in what order matrix was summed. Dependancies
> will be checked and one or more execution units may be available
> or not. The idea of a descrete number of steps occuring in a fixed
> order would be an illusion for some steps may occur simultaneously.

This is true, but irrelevent.  The point is that a procedure
exists, not that it's a linear procedure.
 
> >*There is no view other than the procedural view*.
> >
> >Everything comes down to data transformations over time.  You
> >have yet to come up with an example where this is not true, and
> >you won't, simply because you can't eliminate the time axis.  An
> >algorithm has to have a beginning and an end, an input and an
> >output, and in the middle is a black box known as the "procedure".
> 
> In a sufficently complex vector unit, everything could literally 
> happen at once. So what actually happened in the "black box" might
> never be acutally known, at least as far as the order in which things
> occured. You can of coarse enforce inorder execution.

What does inorder execution have to do with anything?  If I have
2 billion operations happening at once, it doesn't change the fact
that operations occurred in a unit of time.

> There can be "a set of ordered steps for solving a problem", but the 
> order might be an illusion. That a computer is a "deterministic finite
> state machine" is true but you could simulate one with say, groups of
human 
> beings pretending to be registers and doing the logic funcions in there 
> heads, even though people are not "finite state" or *perhaps* 
> deterministic. In this case just when and how certain things occurred
> could be imposible to find out. I could lie and say that I
> did some of the logic when it was someone else. How could you even
> begin to model this as a state machine? Some of the behavour would
> truely be random. The time line would still be there but with no
> way to lay out the events the model loses it's straight "procedural"
> look and feel.

Let me play devil's advocate for non-determinism.  Let's say I had
a Geiger counter (the typical "true" random number generator) and
hooked it up to my computer to give me truly random numbers.  I
use the random values to do mathemetical analysis using the
Monte Carlo method.  I run the simulation, and get the same
result, but the path of getting to the result is different every
time, because of the random nature of algorithm.

So now the question is, so what?  There is no question that I'm
using a non-deterministic statistical algorithm, but there's
still a procedure (the Monte Carlo algorithm), and it still
requires time to execute.  One of the inputs just happens to
be random numbers.

> What if I just randomly guessed at the value of a 
> logic function? Is that procedural? How come one number popped into
> my head and not another?

To answer this question, we need to know what the algorithm
is.  Just coming up with a number in your head is an output,
but what problem was solved by your coming up with the number?

You're approaching it backwards; you're trying to guess the contents
of the black box based on the input and the output.  That's
a different question from implementation of a known algorithm.

> Also, since my debugger can run a program backwards your time line
> may have to be able to go in reverse. :-)

If a computer computes in a forest, and no one is around to
see the result, how was it plugged in? :-)

-- Tim Behrendsen (tim@a-sis.com)