I want to create a re-usable matlab org-babel source block vectsb (say), which takes two vectors from a call statement, performs some operations with them, and returns the result in the call statement. A MWE is as follows

#+NAME: vectsb
#+begin_src matlab :var a=[0], b=[0] :session 

#+CALL: vectsb(a=[1,2,3],b=[3,2,1])

| 1040 | 650 |

I am getting this type of errors in the input arguments

a=[1 (, 2) (, 3)];
Error: Invalid expression. When calling a function or indexing a variable, use
parentheses. Otherwise, check for mismatched delimiters.

No matter how much I read the org-babel manual I can't figure out what I am doing wrong. Partly because there are few examples for Matlab.

1 Answer 1


Here's a version that seems to work (discovered by trial-and-error; and BTW it is using octave, since I don't have matlab):

  #+NAME: vectsb
  #+begin_src octave :var a=[0] :var b=[0] :session

  #+RESULTS: vectsb
  : 0
  #+CALL: vectsb(a=[1 2 3],b=[3 2 1])

  | 4 | 4 | 4 |

The org-babel section of the Org mode manual contains very little about individual languages, which are decribed in a bit more detail in Worg. Unfortunately, the octave/matlab page is very rudimentary: if you are going to work with octave/matlab, you might want to request edit rights to Worg and improve it.

  • Unbelievable. To hit a wall because of not adding :var for each input argument and using spaces instead of commas when passing on the vectors in the call statement. Thank you very much! Org-mode addictiveness has just increased another thousandfold.
    – Ajned
    Commented Oct 25, 2020 at 18:52
  • The separate :var header argument for each variable is required by Org mode and you will just have to get used to it. However, octave (and I presume matlab) syntax requires commas when specifying a literal vector, so it it natural to include them: why Org mode objects to that is not clear to me - I assume that it has something to do with the (generic) parsing of #+CALL: arguments, but I have not checked the code. But I'm glad you are past that road block - and still feel positively towards Org mode!
    – NickD
    Commented Oct 25, 2020 at 20:27
  • Strike that: octave (and matlab?) do NOT require commas when specifying a literal vector - you can use spaces: [1 2 3] works. So Org mode does not support the commas, but it does support the spaces notation. That's much better than I thought.
    – NickD
    Commented Oct 25, 2020 at 22:44

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