It is the same if x is slightly > 1:
--> x=1+%eps
x =
1.
--> acos(x)
ans =
2.107D-08i
--> format(25); x
x =
1.0000000000000002220446
Le 29/01/2019 à 16:55, Carrico, Paul a écrit :
When I scroll to the list, the lowest (positive) value is 8.4^E -08
(works fine) and no %eps .
How Can I check if %eps is in?
*De :*users [mailto:[email protected]] *De la part de*
Stéphane Mottelet
*Envoyé :* mardi 29 janvier 2019 16:50
*À :* [email protected]
*Objet :* [EXTERNAL] Re: [Scilab-users] acos leads to complex values
Le 29/01/2019 à 16:45, Carrico, Paul a écrit :
Dear All
I spent some time in looking for a mistake in my code ; finally
I’ve found that the ACOS of a real vector leads to some complex
values (???)
acos(Scar_P(:,1)./CM_x_CN(:,1))
Are your really sure, because we may have
--> x=-1-%eps
x =
-1.
--> acos(x)
ans =
3.1415927 - 2.107D-08i
S.
(the formula worked so far)
I checked that the input values are correct:
-Comprised between [-1; 1] using MIN and MAX
-Composed only of real values using ISREAL (all the vectors are
correct)
Thus I do not understand why complex values appear ?
May it come from the vectorization ?
Paul
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Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
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Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
http://www.utc.fr/~mottelet
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