plot axis based on a function found online

I found the following function:

http://www.mathworks.ch/support/solutions/en/data/1-216M68/index.html?product=ML&solution=1-216M68

what do I not to do to be able to save that function to my matlab and is there a way somebody else who hasen't downloaded that file is still able to see what it's doing?

Answer 1

[Walter Roberson]

At the bottom of that page there is a header

Related Documents/Files:

below which there is a link for drawaxis.m . Click on that link to download the file. Put the file in a convenient location on your MATLAB path.

Anyone who wishes to execute your code will need a copy of the file. You could include it along with your code.

[Locks]

I have downloaded it, but can I now execute a function with the code:

drawaxis(gca, 'x', 0, 'movelabel', 1)

and matlab automatically knows to which function this is referring to?

[Walter Roberson]

It does not work on the basis of functions or individual lines: it works on the basis of axes, by examining the axes limits, which plotting automatically sets based on the range of values you plotted values over.

[Locks]

I am sorry, but I do not get what I have to do after downloading the file, could you explain to me what excatly is necessary to work with this?

[Walter Roberson]

Use the command

pathtool

and ensure that the directory where you stored drawaxis.m is on the MATLAB path.

Once it is, then after you have done all your other plotting for the axis you want to affect, put the command in your code

drawaxis(gca, 'x', 0, 'movelabel', 1)

[Locks]

doing this, I get this error:

Error using drawaxis (line 87) Specified X crossing outside axis limits

do you have any idea why that could be?

[Walter Roberson]

You did not follow the instructions to "set axis limits appropriately".

YL = get(gca, 'YLim');
YL(1) = min(0, YL(1));
YL(2) = max(0, YL(2));
set(gca, 'YLim', YL);

Note: you might find that once the above is done that you do not need to use drawaxis()

[Locks]

I tried to insert your code, but it doesn't word, here is the full code:

x  =[0:0.01:20]
  y1=blsprice(x,10,0.02,0.2,0.2)-blsprice(10,10,0.02,0.2,0.2)
  y2=max(x-10,0)-blsprice(10,10,0.02,0.2,0.2)

    plot(x,y1,'k',x,y2)

What do I need to change?

    xlabel('Stock Price at Maturity ($)');
    ylabel('Gain ($)');
    axis([8.5 11.5  -0.5 1]);
    set(gca,'xtick',9:0.5:11.5)

    y1L = get(gca, 'yLim');
    y1L(1) = min(0, y1L(1));
    y1L(2) = max(0, y1L(2));
    set(gca, 'yLim', y1L);

    annotation(gcf,'doublearrow',[0.515 0.515],[0.2 0.36])

    text(10.25,-0.2,'Time value')

    set(gca,'Box','off')

[Walter Roberson]

Are you getting an error message? I do not have the toolbox with blsprice() in it, so I cannot test your code.

[Locks]

x  =[0:0.01:20]
  y1=blsprice(x,10,0.02,0.2,0.2)-blsprice(10,10,0.02,0.2,0.2)
  y2=max(x-10,0)-blsprice(10,10,0.02,0.2,0.2)
    plot(x,y1,'k',x,y2)

      xlabel('Stock Price at Maturity ($)');
      ylabel('Gain ($)');
      axis([8.5 11.5  -0.5 1]);
      set(gca,'xtick',9:0.5:11.5)    

      annotation(gcf,'doublearrow',[0.515 0.515],[0.2 0.36])    
      text(10.25,-0.2,'Time value')    
      set(gca,'Box','off')

this code is perfectly working so I guess it can't be blsprice ()

could you tell me what I excatly ned to change in my code and where I have to place the new elements?