How can I plot output from a function which returns multiple values in Python?

Question

Short intro

I'm calculating and plotting spectral energy of planets orbiting pulsar from given data.

I have previously ordered all data in a list variations with dimensions [172, 2] (172 rows and 2 columns).

Firstly, I have to calculate parameters of a presupposed model and spectral energy accordingly (from those very parameters).

To do that, I defined a function under which I defined the presupposed model and find_fit function which takes the model and variations data.

Code

 var('a, b, t')

def spectrum(omega):

    model = a*sin(omega*t) + b*cos(omega*t)
    fit = find_fit(variations, model, parameters= [a, b], variables = [t], solution_dict = True)
    sp_en = ((fit[a])**2 + (fit[b])**2)/2

    return fit[a], fit[b], sp_en

Then I call the function and print values:

c, v, energy = spectrum(20)   #enter arbitray angular frequency here
print "Values for the given angular frequency : \n \n a = %f, b = %f, spectral_energy = %f " % (c, v, energy)

Now I have to plot only sp_en output.

"Semi-solution"

It is easy to that if a spectrum function return only sp_en. It is sufficient than to write:

var('t')
plot(spectrum(t), (t, 1, 100))

Which returns: energy-omega plot

The question than is: how do I plot this function if I want to print all three outputs?

steven · Answer 1 · 2016-02-19T15:48:48.277

0

Just call the plot function with only the energy variable

omega=10
c, v, energy = spectrum(omega)   #enter arbitray angular frequency here
print "Values for the given angular frequency : \n \n a = %f, b = %f, spectral_energy = %f " % (c, v, energy)

plot(energy, (omega, 1, 100))

edited Feb 19 '16 at 15:48

answered Feb 18 '16 at 16:33

steven

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Thanks for the answer. This line doesn't work. I get the error: "Variable omega is not defined". – userzg Feb 19 '16 at 15:40
I just reused it from your func. definition, edited so it works now. – steven Feb 19 '16 at 15:48

score 0 · Accepted Answer · answered Feb 18 '16 at 16:33

0

Just use indexing on the return value from spectrum:

plot(spectrum(t)[2], (t, 1, 100))

answered Feb 18 '16 at 16:33

tmdavison

64,360
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Thanks for the answer. I didn't know I can use indexing this way. Indexing did plot only energy. But still something was missing. This is the correct solution. `plot(lambda t:spectrum(t)[2], (t, 1, 100))` – userzg Feb 19 '16 at 15:42

How can I plot output from a function which returns multiple values in Python?

Short intro

Code

"Semi-solution"

2 Answers2

Linked