Invalid expression, check for mismatched delimiters. Trying to form a matrix using brackets.

I keep getting the error message: >> abc2sc

File: abc2sc.m Line: 21 Column: 28

Invalid expression. When calling a function or indexing a variable, use

parentheses. Otherwise, check for mismatched delimiters.

Here is my preliminary code.

function [symcomp] = abc2sc(fabc)
rankfabc=length(fabc(1,:));
if rankfabc == 2
    mag=fabc(:,1); ang=pi/180*fabc(:,2);
    fabcr=mag.(cos(ang)+jsin(ang));
elseif rankfabc ==1
    fabcr=fabc;
else
    fprintf('\n  Three phasors must be expressed in a one column array in rectangular complex form \n')
    fprintf('  or in a two column array in polar form, with 1st column magnitude & 2nd column \n')
    fprintf('  phase angle in degree. \n')
    return, end
a=cos(2*pi/3)+jsin(2*pi/3);
A = [1   1   1; 1 a^2  a; 1 a  a^2];
fa012=inv(A)*fabcr;
symcomp= fa012;
%scpolar = [abs(fa012)  180/piangle(fa012)];
%fprintf(' \n Symmetrical components \n')
%fprintf(' Magnitude  Angle Deg.\n')
%disp(scpolar)
fabc0=fa012(1) [ 1; 1; 1 ];
fabc1=fa012(2) [ 1;  a^2;  a ];
fabc2=fa012(3) [ 1;  a;  a^2 ];
end

Answer 1

[Jan]

What is the meaning of this line:

fabcr=mag.(cos(ang)+jsin(ang));

This treats "mag" as a struct and tries to interprete "cos(ang)+jsin(ang)" as field name. What is "jsin"? Maybe you mean:

fabcr = mag .* (cos(ang) + 1j * sin(ang));

The error appears in these lines, I guess (by the way, if you post the complete error message, the readers would see, which line is failing):

fabc0=fa012(1) [ 1; 1; 1 ];
fabc1=fa012(2) [ 1;  a^2;  a ];
fabc2=fa012(3) [ 1;  a;  a^2 ];

What is the purpose of these lines? Did you forget some * characters for a multiplication? The output fabc0/1/2 is not used anywhere, so whay not simply omitting these lines?

This looks suspicious also:

a=cos(2*pi/3)+jsin(2*pi/3);

Did you really create a function called jsin()?

By the way, prefer the backslash operator instead of calling inv(). See: inv