integration using s-functions in simulink

function task1(block)
  setup(block);

function setup(block)

    block.NumDialogPrms = 3;
    block.DialogPrmsTunable={'a','b','c'};
    block.NumInputPorts  = 1;
    block.NumOutputPorts = 1;
    block.SetPreCompInpPortInfoToDynamic;
    block.SetPreCompOutPortInfoToDynamic;
    block.InputPort(1).Dimensions        = 1;
    block.InputPort(1).DirectFeedthrough = false;
    block.OutputPort(1).Dimensions       = 1;
    block.SampleTimes = [0 0];
    block.NumContStates = 1;
    block.SimStateCompliance = 'DefaultSimState';
    block.RegBlockMethod('InitializeConditions',    @InitConditions);  
    block.RegBlockMethod('Outputs',                 @Output);  
    block.RegBlockMethod('Derivatives',             @Derivative);  

function InitConditions(block)
 block.ContStates.Data = block.DialogPrm(3).Data;

function Output(block)
 block.OutputPort(1).Data = block.ContStates.Data;

function Derivative(block)
 a = block.DialogPrm(1).Data;
 b = block.DialogPrm(2).Data;
 c =  block.DialogPrm(3).Data;

       if (block.ContStates.Data <= a && c < 0) || (block.ContStates.Data >= b && c > 0)
         block.Derivatives.Data = 0;
       else
         block.Derivatives.Data = c;
       end

this is my code for making s-function written in script file ".m" format. it is giving the following errors-

1.Invalid setting specified for the tunability of the dialog parameters of 'task1' in 'untitled/integration'. The tunability for dialog parameters should be a [1x3] cell array of the form {'Tunable','Nontunable','SimOnlyTunable',...}.

2.Error evaluating the initialization for M-S-Function 'task1'. Invalid setting specified for the tunability of the dialog parameters of 'task1' in 'untitled/integration'. The tunability for dialog parameters should be a [1x3] cell array of the form {'Tunable','Nontunable','SimOnlyTunable',...}. The following is the MATLAB call stack (file names and line numbers) that produced this error: 
['C:\Users\Admin\Downloads\The Grand Design - Stephen Hawking (Audiobook) [128k mp3] politux\task1.m'] [8]
['C:\Users\Admin\Downloads\The Grand Design - Stephen Hawking (Audiobook) [128k mp3] politux\task1.m'] [2]

how do i resolve this problem?? thanks.

Answer 1

[Kaustubha Govind]

block.DialogPrmsTunable must be a cell-array that contains any of the following strings: 'Tunable','Nontunable','SimOnlyTunable'. You cannot say:

block.DialogPrmsTunable={'a','b','c'};

'a', 'b' and 'c' are not valid strings.