Dear all,
I found a link to the Numerical Mathematics Consortium
http://www.nmconsortium.org/index.aspx
Their rationale can be summarized (as far as I understood) by the
paragraphs which I copied from their homepage and pasted below.
Maybe this could be of interest also for the development of R?
Best,
Roland
And here the copy+paste from their homepage:
As modern numerical programming languages have replaced FORTRAN as the
language of choice, and as new interactive design and development tools
were introduced over the years, the standardized representation of
common functions began to disperse again. The problem is as simple as
looking at the Fast Fourier Transform (FFT) function:
Mathcad
t := 0..127
x := sin(2.p..01.t)
w :=fft(x)
MATLAB
t = 0:127
x = sin(2*pi*.01*t)
w = fft(x)
Size of w:
Mathcad = 65
MATLAB = 128
As in this case, even if the syntax is identical, the calculations yield
different results!
By definition, the FFT function of real data produces a result where the
second half of the data is the complex conjugate of the first half.
Mathcad uses this and only returns the first half of the data (i.e. N/2
+ 1). MATLAB returns all of the data (N). Both are valid
interpretations.
The Numerical Mathematics Consortium is proposing a semantic standard
for core numerical functions so as to help solve issues such as this.
+++++
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