On Wednesday, December 14, 2016 6:46 AM, Patrick Dupre <pdupre@xxxxxxx> wrote:
Thank very good
However, there is something that I do not understand
I define
W1=0.2
z(x) = (x + W1*{0,1})
w(x) = faddeeva (z (x))
and
Voi (x) = voigt (x, W1)
Voi (x) and real (w(x)) are exactly the same
Now,
d_w (x) = - 2 * z (x) * w (z (x)) + 2*{0,1}/sqrt(pi) " which is the derivative
D_voi(x,del) = (Voi (x+del) - Voi (x-del)) / 2 / del
now
plot [-4:4] D_voi(x,0.001)
and
plot [-4:4] real (d_w (x))
are different except for W1=0
What am I doing wrong?
It seems that the issue is with the faddeeva, or when I my calls!
Thank.
===========================================================================
Patrick DUPRÉ | | email: pdupre@xxxxxxx
Laboratoire de Physico-Chimie de l'Atmosphère | |
Université du Littoral-Côte d'Opale | |
Tel. (33)-(0)3 28 23 76 12 | | Fax: 03 28 65 82 44
189A, avenue Maurice Schumann | | 59140 Dunkerque, France
===========================================================================
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I am now a bit confused. {0,1} represents the number 0 + 1i correct?
Then I would believe that Mr. Howell is correct in that the magnitude should be called upon since to get a real number function. His comment
<quote>
I am not a mathematician, but I have programmed extensively
with complex numbers. W(x)=faddeeva(z(x)) will return a complex,
right?
The magnitude of a complex is its full value, so you would need
the sqrt(real^2+imag^2) would you not?
</quote>
z(x) is the one defined with the z(x) = (x + W1*{0,1}) which would be z(x) = x + 0*i which is just x because the W is 0. If the function is defined correctly and I have a strong hunch that it is, then there is a problem with gnuplot and it has to be a bug somewhere. We can try plotting the function using plotshare.com which is a frontend to gnuplot.
There is no output from the plots check in
http://www.plotshare.com/index.ws/plot/432515199
It actually plots one function only and the other one does not come up.
Best Regards,
Antonio A. Olivares
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