CODEWITHSUNDEEP
matlabplotmatlab-figuregraphic
Jac
Jac

Reputation: 101

Error plot matlab

i have a list of functions:

[ x - 3^(1/2)/2, x - 4967757600021511/81129638414606681695789005144064, x + 3^(1/2)/2, x - 4160783518353059/4503599627370496, x - 1723452963400281/4503599627370496, x + 3446905926800561/9007199254740992, x + 4160783518353059/4503599627370496, x - 8566355544790271/9007199254740992, x - 2647149443198255/4503599627370496, x - 4967757600021511/81129638414606681695789005144064, x + 5294298886396509/9007199254740992, x + 8566355544790271/9007199254740992, x - 8700286382685973/9007199254740992, x - 2^(1/2)/2, x - 291404338770025/1125899906842624, x + 2331234710160199/9007199254740992, x + 2^(1/2)/2, x + 2175071595671493/2251799813685248, x - 8781369964030313/9007199254740992, x - 7042111946219083/9007199254740992, x - 3908077291623905/9007199254740992, x - 4967757600021511/81129638414606681695789005144064, x + 122127415363247/281474976710656, x + 880263993277385/1125899906842624, x + 4390684982015157/4503599627370496]

and I would like to plot the functions with this command "plot(funciones_che(1))" but when I make the plot throws me the following error:

Error using plot. A numeric or double convertible argument is expected

I have also tried x = -10: 10 and plot (x, funciones_che (1)) but I get the same error

Upvotes: 0

Views: 3272

Answers (1)

Mad Physicist
Mad Physicist

Reputation: 114518

You do not have a vector of functions. The variable funciones_che is just a long concatenated sequence of numbers. If you run size(funciones_che), you should get 1 x m*n where m is length(x) and n is the number of "functions" you have. Having a true vector of functions would actually complicate your life unnecessarily.

If you have a symbolic expression somewhere along the line, it may be a bit difficult to clear: http://www.mathworks.com/help/symbolic/clear-assumptions-and-reset-the-symbolic-engine.html. My recommendation is to reset the entire symbolic engine with all its assumptions just to be safe: reset(symengine).

MATLAB is very good at plotting matrices like the one you have, but the size has to be right:

  1. Separate your plots with semi-colons (;) rather than commas (,):

    funciones_che=[ x - 3^(1/2)/2; x - 4967757600021511/81129638414606681695789005144064; x + 3^(1/2)/2; .....]

    Now size(funciones_che) will be n x m.

  2. Transpose the matrix (to make plot interpret it correctly):

    funciones_che = funciones_che';

    Now size(funciones_che) will be m x n.

Plot as you wanted to: plot(funciones_che(:, 1)) for the first vector, or plot(funciones_che) to put all of them on the same plot. If you are not interested in the second version, you do not have to transpose the matrix. If you do not transpose the matrix, plot using plot(funciones_che(1, :)) instead.

Final point: you do need to initialize x, for example to -10:10 as you tried.

Upvotes: 1

Related Questions