problem in calling a function, it does not recognize "switch case"

Please suggest the solution for the following problem. I am doing this in MATLAB 2021a. Thanks

I have three functions (1). function DSSK_Cons_Diagram = DSSK_Cons_Diagram_Gen(Nt )

(2). function DSM_Cons_Diagram=DSM_Cons_Diagram_Gen(Nt ,M)

(3). function DSMTConstellation_Mat = DSMT_Cons_Diagram_Gen(DSMT_SyS ,Nt ,M)

(1) and (2) works properly when I call them separately in the command window but the (3) has a problem it always says "unknown system". To call (3), I am writing like this,

DSMT_SyS =["dssk", "dsm"];  %DSMT_SyS is A string indicating the DSMT system  for :
% −’DSSK’ for differential space shift keying ;
% − DSM’ for differential spatial modulation .
Nt=2,M=2; 
DSMT_Cons_Diagram_Gen(DSMT_SyS ,Nt ,M)

The (3) is written here,

function DSMTConstellation_Mat = DSMT_Cons_Diagram_Gen(DSMT_SyS ,Nt ,M)
switch lower(DSMT_SyS)
    case 'dssk'
        DSMTConstellation_Mat = DSSK_Cons_Diagram_Gen(Nt ) ;
    case 'dsm'
        DSMTConstellation_Mat = DSM_Cons_Diagram_Gen(Nt ,M) ;
    otherwise
        error('Unknown system' )
end
end

[Stephen23]

You cannot supply SWITCH with a non-scalar string array as you are doing, you must provide it with a scalar string (or a character vector). You could use a loop, ARRAYFUN, or CELLFUN.

[Dyuman Joshi]

1 - Your input is string and the comparison is done with char (switch statement)

2 - Your input is an array while the comparison is done for a (singular) element

EDIT - My first statement is incorrect, as showed by Stephen below.

[Stephen23]

@Dyuman Joshi: the SWITCH operator accepts STRING objects (and all objects that have an EQ method):

str = "hello"; % string
switch str
    case 'hello'
        disp world
    otherwise
        disp failed
end

world

The problem is that the OP provides a non-scalar string array.

[Dyuman Joshi]

@Stephen23, I was not aware of this. Thanks for the info. I will edit my comment accordingly.

Also, If you don't mind me asking, What do you mean by EQ method?

[Sajid Sarwar]

Stephen23 Thanks for the answer. I got it.

[Stephen23]

"What do you mean by EQ method?"

https://www.mathworks.com/help/matlab/ref/eq.html

https://www.mathworks.com/help/matlab/ref/switch.html#description

methods('string')

Methods for class string:

append          contains        eq              extractAfter    gt              issorted        lt              pad             reverse         startsWith      
cellstr         count           erase           extractBefore   insertAfter     join            matches         plus            sort            strip           
char            double          eraseBetween    extractBetween  insertBefore    le              ne              replace         split           strlength       
compose         endsWith        extract         ge              ismissing       lower           or              replaceBetween  splitlines      upper           

[Dyuman Joshi]

Oh, okay, eq is short for equality, alright. Thanks for the info, it's quite helpful!

[Steven Lord]

Most of the operators have a function associated with them that you can overload to overload that operator (for example, plus is the function you overload to customize how your class works with the + operator.) See the table on this documentation page for more information about the operators and their corresponding function forms.