[Scilab-users] Problems with plot 3d. Function fplot3d

[Serge Steer]

The question is: how do you want to represent complex numbers in your 3D plot? 
plot3d function only represent the real part... 

Serge Steer 

----- Mail original -----

> De: "Ubirajara Marques da Cruz" <biracruz at cemig.com.br>
> À: users at lists.scilab.org
> Envoyé: Vendredi 7 Juin 2013 22:46:37
> Objet: [Scilab-users] Problems with plot 3d. Function fplot3d

> To user support,

> Recently I was studing a function that i wanted to plot it. This
> function is a 3d equation that I wrote above:

> I try to use fplot3d to plot following interval x=0:0.01:1 and
> y=0:0.01:3.
> When I analise the results this function has positive and negative
> numbers to plot but when i plot it it only show positive numbers.

> I look for the answers about square root of negative numbers and i
> found help tips that show into this case the answer is a complex
> number. Then I see that matrix z is a vector that has real numbers
> and complex numbers(they are mixed) and fplot3d shows a result very
> diferente of I was expecting.

> If point is a real number fplot3d plot right surface and if the point
> is a complex number it shows a wrong surface. What must i do to
> solve this problem?

> Follow, I send code that I´ve been use into scilab 4.1.2 (scipad)

> x=0:0.01:1 ;y=0:0.01:3
> deff(‘z=f(x,y)’,’z=( (1-exp(-5*x))-y)^(1/3)’)
> clf()
> fplot3d(x,y,f,alpha=60,theta=60)

> Down part of this graphic is mirrored to up side and values are
> wrong. The right result that i was expecting is the surface to be
> drawnt to negative side.

> Thank you for yours helps.

> Ubirajara Marques da Cruz
> Engenheiro de Projetos Elétricos
> Gerência de Engenharia Eletromecânica de Expansão da Geração e de
> Fontes Alternativas
> Diretoria de Geração e Transmissão
> Companhia Energética de Minas Gerais – Cemig
> Telefone: 55 (31) 3506-4602
> Email: biracruz at cemig.com.br
> www.cemig.com.br
> Descrição: cid:image002.jpg at 01CD973D.26DD29C0

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