Richard Clark wrote:

Hi John,

Yes, this confirms the shift to double precision in EZNEC lowering
artifacts in the fine data.

However, I think it goes beyond simple matters of single or dual
precision math. When I was designing Fourier Analysis packages while
I was on contract to HP, I discovered there was a world of variability
in math library's transcendental functions.

Microsoft's product was abysmal, whereas Borland's was superlative. A
telling example is that for the transform of a sine wave into the
frequency domain under Microsoft math libraries, the noise floor was
at 60 to 80 dB below the fundamental peak with harmonics. When I
switched to Borland math libraries, there was a single bin response
and the noise floor plunged to 200dB down!

snip
73's
Richard Clark, KB7QHC

Richard

I am not surprised with your result after having used various MS
compilers over the years. Do you have any idea what the real
differences were in the libraries? Borland C always seemed better, more
robust at error handling, and more accurate.

I noticed similar problems back in the late 80's with MS C, but never
really needed the precision, and work pressure being what it was....

tom
K0TAR

On Wed, 27 Sep 2006 19:47:06 -0500, Tom Ring
wrote:

Do you have any idea what the real
differences were in the libraries?

Hi Tom,

I can only speculate from my experience coding various expansion
series before the 8087 was generally available. My guess is they went
with the first one in a cookbook - Newton's method comes to mind, but
that is of vague recollection. It is generally useful as a first pass
method. M$ became extinct in the Pascal marketplace soon after. I
also moved on into C++ in the late 80s (a local company here wrote one
of the first cross-compilers).

The M$ crowd thought they would take that one on too. In 1990 they
asked me to come in and give classes. What a fiasco. The first
question was how to do inline code. They were arrogant to the point
of wanting to call "their" version C++++ with the +s stacked in pairs
to produce #. Can anyone guess how long C-sharp took to get to market?

73's
Richard Clark, KB7QHC