I have written some functions in matlab.Now I need to get their outputs to C# .net form.I could success fully connect them through .Net Assembly and able to get output of a function which returns only one output to c#.Now I want to do it with a function which returns multiple outputs.Is there any particular way of doing this?????
thanks...
there are different signrature of the method available in the DLL, just use the proper one,
put the first input argument of the method as the number of outputs, then it will return an array of MWArray as outputs : (i.e below, 2 indicates that I expect to have an array of outputs with size 2)
MWArray[] res = MatlabDll.callMethod(2, x, y);
C# uses the Tuple Class for solving this issue.
Related
I have a script Function.m such that for example, when I write TEST=Function(1,2), I have TEST.x1=4 and TEST.x2=[5,6,7]. I want to use fsolve to help me find input. To be precise, I want to define a function, say a=#(y)Function(1,y)-4 so that when I use [z,vector]=fsolve(#(y)a(y),5), matlab can help me to obtain z=2 and vector=[5,6,7].
I would like to solve it by defining the same structure New_Function.m as Function.m such that it returns x1 values, i.e., TEST=New_Function(1,2) gives TEST=4 only. Then I write new_a=#(y)New_Function(1,y)-4 and solve z=fsolve(#(y)new_a(y),5) and define new_vector=Function(1,z) so that I can access new_vector.x2.
I want to know if it is possible to do my task without defining a new script or amending the content in the existing script. How to write code?
Since Matlab does not allow further referencing the result of a function call, you may need to help yourself with getfield. In your example (provided I got it right), it would be something like New_Func = #(y) getfield(Function(1,y),'x1'). This would take one scalar and return one scalar, i.e., New_Func(y) gives the field value of the struct returned by Function(1,y) associated to the field x1.
For example I have a 1*30 structure a.field, when I type a(:).field in command window it just iteratively display a(1).field, a(2).field,... However, when I was trying to assign a(:).field to another variable b, what b get is just a(1).field.
BTW, if I attampt to pass a(:).field to a function, Matlab just throws an error "too many input arguments".
What is the mechanism behind? My guess is that matlab threat colon equivlant to the first element during assignment, is that true?
You need to add brackets, otherwise matlab don't understand that your trying to store an array:
b = [a(:).field]
Another option that provide similar result:
b = horzcat(a(:).field)
I ran a quick test to see how if deals with multiple input values. It appears that the default behavior is to apply and to the collection of values, but I couldn't find any documentation. Can anyone confirm or provide a counterexample?
>> if([1,1,1]) disp(sprintf('hi'));end;
hi
>> if([1]) disp(sprintf('hi'));end;
hi
>> if([1,1,0]) disp(sprintf('hi'));end;
EDIT: to clarify, I don't intend to try to use this "feature," but wanted to be sure I knew how erroneous input would be handled. Suppose, for example, your code read
if(my_function) and the (badly written) my_function usually returns a single value but occasionally returns multiple values. Good practice, of course , would parse the returned values appropriately and feed a single value to if.
I don't find any practical reason to create an if statement which depends on anything but a scalar.
Regarding what's done in MATLAB practically?
You may assume MATLAB applies the function all on the input of the if statement.
This will hold as intuition given the array is non empty.
For example, if we have array - array4Example which is not empty, the statement if on the array - if(array4Example) is equivalent of the statement if on the scalar - if(all(array4Example(:))).
This matches the documentation if the if function.
depfun's documentation gives the following:
[list,builtins,classes] = depfun(fun) returns the MATLAB classes that
fun requires.
Excellent, this is exactly what I want. However, when I call that on my function it tells me there are too many output arguments. So, I tried
list = depfun(Dynamo)
and to my surprise the same error occurred. How can this be? depfun(Dynamo) must return at least one argument, no?
What I'm trying to do is to create a dependency graph in the way as suggested by Andrew Janke in Automatically generating a diagram of function calls in MATLAB
The following works and gives me a nice report, but I don't want the graph to contain all the hidden functions which is why I'm opting for depfun.
profile on
Dynamo;
profile off
profview
Any insight is much appreciated
You need to pass the function argument as a string
>> [list,builtins,classes] = depfun( 'Dynamo' )
Is there an idiomatic way in Matlab to bind the value of an expression to the nth return value of another expression?
For example, say I want an array of indices corresponding to the maximum value of a number of vectors stored in a cell array. I can do that by
function I = max_index(varargin)
[~,I]=max(varargin{:});
cellfun(#max_index, my_data);
But this requires one to define a function (max_index) specific for each case one wants to select a particular return value in an expression. I can of course define a generic function that does what I want:
function y = nth_return(n,fun,varargin)
[vals{1:n}] = fun(varargin{:});
y = vals{n};
And call it like:
cellfun(#(x) nth_return(2,#max,x), my_data)
Adding such functions, however, makes code snippets less portable and harder to understand. Is there an idiomatic to achieve the same result without having to rely on the custom nth_return function?
This is as far as I know not possible in another way as with the solutions you mention. So just use the syntax:
[~,I]=max(var);
Or indeed create an extra function. But I would also suggest against this. Just write the extra line of code, in case you want to use the output in another function. I found two earlier questions on stackoverflow, which adress the same topic, and seem to confirm that this is not possible.
Skipping outputs with anonymous function in MATLAB
How to elegantly ignore some return values of a MATLAB function?
The reason why the ~ operator was added to MATLAB some versions ago was to prevent you from saving variables you do not need. If there would be a syntax like the one you are searching for, this would not have been necessary.