Plotting a matrix

[Dunnomuch]

Hi,

I've got a little problem in plotting a matrix that is build up in a class. Cause I've build it up in a class, I can't just plot the different arrays out of which it would consist when you build it up like this:

[[...],[...], ... , [...]]

I've tried to plot it by making a loop that consistently plots the rows which have f1, f2 and t in it (Respectively being the first function, the second function and the time). The problem I've got is that when I use this method, I plotting a part of my graph twice (you can see 2 lines that indicate that de functions go over this part twice). This is not what I should get.

[Glenton]

Hi

I'm afraid your question doesn't make much sense. Can you clarify what you mean by plot, and maybe post some code that helps explain the problem? What should you get? Unfortunately computer programmes have an annoying habit of doing what they're told...;P

[Dunnomuch]

Hi,

The matrix I mean looks like this:

class Matrix(object): 
    def __init__(self, kolommen, rijen): 
        self.kolommen = kolommen 
        self.rijen = rijen 
        # Creeer matrix met nullen
        self.matrix = [] 
        for i in range(rijen): 
            ea_rijen = [] 
            for j in range(kolommen): 
                ea_rijen.append(0) 
            self.matrix.append(ea_rijen) 
  
    def plaatselement(self, kolom, rij, v):   #Zet element v op plaats [kolom, rij]
        self.matrix[kolom-1][rij-1] = v 
  
    def neemelement(self, kolom, rij):  #Neemt element op plaats [kolom, rij]
        return self.matrix[kolom-1][rij-1] 
  
    def __repr__(self): #Dient om matrix te printen
        outStr = "" 
        for i in range(self.rijen): 
            outStr += 'Rij %s = %s\n' % (i+1, self.matrix[i]) 
        return outStr

I just fill it with numbers which are the solution of an N-dimensional ODE. The solving method I use is Forward Euler, but it shouldn't matter what's in the matrix. I now want to plot 2 collums out of this matrix. Is there a way to do this?

[Glenton]

Assuming you've got matplotlib installed (which you should do, along with numpy), the following will use your class (unadjusted) and plot one column against another graphically:

class Matrix(object): 

    def __init__(self, kolommen, rijen): 

        self.kolommen = kolommen 

        self.rijen = rijen 

        # Creeer matrix met nullen

        self.matrix = [] 

        for i in range(rijen): 

            ea_rijen = [] 

            for j in range(kolommen): 

                ea_rijen.append(0) 

            self.matrix.append(ea_rijen) 

 

    def plaatselement(self, kolom, rij, v):   #Zet element v op plaats [kolom, rij]

        self.matrix[kolom-1][rij-1] = v 

 

    def neemelement(self, kolom, rij):  #Neemt element op plaats [kolom, rij]

        return self.matrix[kolom-1][rij-1] 

 

    def __repr__(self): #Dient om matrix te printen

        outStr = "" 

        for i in range(self.rijen): 

            outStr += 'Rij %s = %s\n' % (i+1, self.matrix[i]) 

        return outStr 



#Create matrix

M=Matrix(10,10)

for i in range(10):

    for j in range(10):

        M.plaatselement(i,j,i+j)



#Plot 4th column vs 6th column

import pylab

pylab.plot(M.matrix[:][3],M.matrix[:][5])

pylab.show()