i had a code that c send back 1 number (mex)
the matlab code was
vMsg=unit32(Gateway_test_app(2))
now i added 1 more return value to Gateway_test_app(2) which is s STRING
what i need to do to get the two values back
i was thinking about something like this:
[vMsg,errMsg]=??????(Gateway_test_app(2))
what should i put in the ????? place?
thx for any help
johnny.
ps
using codegen and need not to get err when building
First call the function and store the two outputs, then run your extra function unit32 (what does it do, by the way?) on the first output only:
[vMsgOriginal, errMsg] = Gateway_test_app(2);
vMsg = unit32(vMsgOriginal);
This assumes that you don't want to process your new string output through your unit32 function.
Related
I'm trying to do a pytest on a function without return value, but obviously value is None in pytets. I was wondering if there is a solution for that?
here is function which I'm trying to test:
def print_top_movies_url():
for item in movie_link[:100]:
print item.contents[1]
The best thing to do would be to separate getting the top movies and printing them.
For example, you could have a top_movie_urls which looks like this:
def top_movie_urls():
urls = []
for item in movie_link[:100]:
urls.append(item.contents[1])
return urls
(or make it a generator function)
That's easy to test, and wherever you call it, you can now just do something like print('\n'.join(top_movie_urls())).
If you really want to test the output instead, you can use pytest's output capturing to access the output of the tested function and check that.
I have a structure such as:
specimen.trial1 = 1
I now want to add another trial to the specimen, so that
specimen.trial1 = 1
specimen.trial2 = 2
I can do this without a problem within the workspace and command window. But, if I'm using a function to calculate the numbers for each trial (with dynamic fields), the new field and value erases the previous one. Eg:
function [specimen] = dummy(trial,value)
specimen.(trial) = value
end
run the function:
[specimen] = dummy('trial1',1)
then run the function again with different inputs, but keeping the structure intact in the workspace
[specimen] = dummy('trial2',2)
Instead of getting a structure with 2 fields, I get just one with Trial2 being the only field. Does that make any sense? What would like is to use the outputs of a function to progressively add to a structure.
Thank you,
Chris
Yes it makes sense, because you're creating a new struct specimen within your function.
Solution: pass the the previous specimen to the function as well.
function [specimen] = dummy(specimen,trial,value)
specimen.(trial) = value
end
and call:
[specimen] = dummy(specimen,'trial1',1)
or alternativly leave out the assignment at all and use the following
function [output] = dummy(value)
output = value
end
and call:
[specimen.trail1] = dummy(1)
which really depends on what you actually want to do. Put passing a name to a function which uses this name to define a struct is a little pointless unless you "use" that name otherwise. Also if you want to have input-dependent dynamic names you'd also go with the first alternative
let us suppose that we have following function
function [y1,y2,y3,y4]=mystery(a,x);
y1=a*x;
y2=a*x^2;
y3=a^2*x^2;
y4=a*x^3+5;
end
now what i want to make sure is order of result returned from this code,for instance
[y1,y2,y3,y4]=mystery(3,5);
does it return in reverse order or directly in direct form?i meant when m file is executed does it first return last result,then previous of last line and so on?thanks in advance
The parameters are always returned in the order of the declaration. The order of evalutation does not matter. So, in your case, you will always have the order [y1,y2,y3,y4].
Edit:
If you want to access the second or third parameter only, you can do [~,y2]=mystery(1,2) or [~,~,y2]=mystery(1,2) respectively.
Matlab executes line by line in the script. The first line is always executed first.
I've been looking throught the documentation, but can't seem to find the bit I want.
I have a for loop and I would like to be able to view every value in the for loop.
for example here is a part of my code:
for d = 1 : nb
%for loop performs blade by blade averaging and produces a column vector
for cc = navg : length(atbmat);
atb2 = (sum(atbmat((cc-(navg-1):cc),d)))/navg;
atbvec2(:,cc) = atb2;
end
%assigns column vector 'atbvec2' to the correct column of the matrix 'atbmat2'
atbmat2(d,1:length(atbvec2)) = atbvec2;
end
I would like to view every value of atb2. I'm a python user(new to MATLAB) and would normally use a simple print statement to find this.
I'm sure there is a way to do it, but I can't quite find how.
Thankyou in advance.
you can use disp in Matlab to print to the screen but you might want to use sprintf first to format it nicely. However for debugging you're better off using a break point and then inspect the variable in the workspace browser graphically. To me, this is one of Matlab's best features.
Have a look at the "Examine Values" section of this article
The simplest way to view it everywhere is to change this line:
atb2 = (sum(atbmat((cc-(navg-1):cc),d)))/navg;
Into this, without semicolon:
atb2 = (sum(atbmat((cc-(navg-1):cc),d)))/navg
That being said, given the nature of your calculation, you could get the information you need as well by simply storing every value of abt2 and observing them afterwards. This may be done in atbmat2 already?
If you want to look at each value at the time it happens, consider setting a breakpoint or conditional breakpoint after the line where abt2 is assigned.
I am getting an error when running matlab code. Here I am trying to use one of the outputs of previous code as input to my new code.
??? Reference to non-existent field 'y1'.
Can anyone help me?
A good practice might be to check if the field exists before accessing it:
if isfield( s, 'y1' )
% s.y1 exists - you may access it
s.y1
else
% s.y1 does not exist - what are you going to do about it?
end
To take Edric's comment into account, another possible way is
try
% access y1
s.y1
catch em
% verify that the error indeed stems from non-existant field
if strcmp(em.identifier, 'MATLAB:nonExistentField')
fprintf(1, 'field y1 does not exist...\n');
else
throw( em ); % different error - handle by caller?
end
end
Have you used the command load to load data from file(s)?
if yes, this function overwrite your current variables, therefore, they become non-existent, so when you call, it instead of using:
load ('filename');
use:
f=load ('filename');
now, to refer to any variable inside the loaded file use f.varname, for
example if there is a network called net saved within the loaded data you may use it like:
a = f.net(fv);
I would first explain my situation and then give the solution.
I first save a variable op, it is a struct , its name is coef.mat;
I load this variable using coef = load( file_path, '-mat');
In a new function, I pass variable coef to it as a parameter, at here, the error Reference to non-existent field pops out.
My solution:
Just replace coef with coef.op, then pass it to the function, it will work.
So, I think the reason behind is that: the struct was saved as a variable, when you use load and want to acess the origin variable, you need point it out directly using dot(.) operation, you can directly open the variable in Matlab workspace and find out what it wraps inside the variable.
In your case, if your the outputs of previous code is a struct(It's my guess, but you haven't pointed out) and you saved it as MyStruct, you load it as MyInput = load(MyStruct), then when use it as function's parameter, it should be MyInput.y1.
Hops it would work!
At first load it on command window and observe the workspace window. You can see the structure name. It will work by accessing structure name. Example:
lm=load('data.mat');
disp(lm.SAMPLE.X);
Here SAMPLE is the structure name and X is a member of the structure