In Matlab, in order to change the value of a block I do
set_param('model/V','Amplitude','100')
and the value of V is 100. But if I do
for i=1:10
set_param('model/V','Amplitude','P(i)')
...
end
The it stores the value of V as P(i). But in order to access the i-th element of the 20-by-1 P matrix, I need to refer to it by P(i). What is my error?
Change the value to string using:-
set_param('model/V','Amplitude',num2str(P(i)) );
Also it will set the value of 'model/V' to P(20) i.e. last one.
You might want to loop through the current blocks too
Something like : (just example)
set_param(['model/V' num2str(i)],'Amplitude',num2str(P(i)) );
for model/V1, model/V2,...model/V20 .
Related
I have an if statement something like
t(2,5)
P(6,1)
if x:length(t)
t(2,3)>P
P=0
elseif t(2,3)<P
P=1
end
basically what I want to achieve is a loop that runs through t and compares it to p, if the value of t is smaller than the value of P a new matrix should be created and record the value as "1", if the value of t is bigger than the value of P record value as "0", I can't get it to work unfortunately.
If you just want to check if the values in array/matrix t is less than a certain constant value, say P, then better run t<P. That will do the job.
If t and P are both matrices, of equal length, then also you can use t<P. No need for loops or if statements.
I have a Matlab function which returns an array with probability alpha and nothing (i.e. an empty array) with probability 1-alpha:
function [binary_array_e1 , binary_array_e2 ] = croiser(binary_array_p1,binary_array_p2,alpha )
binary_array_e1=[];
binary_array_e2=[];
compt=1;
if (rand <= alpha)
% some stuff that will put sth in binary_array_e1 and binary_array_e2
end
My question is: how should I manage the fact that the function could return empty arrays at the call of the function? Is something like:
[binary_array_e1 , binary_array_e2]=croiser(binary_array_p1,binary_array_p2,alpha);
be sufficient?
If you want to return an empty variable from a function call, you are totally allowed to do it and you are on the right path. Initialize your variables as empty at the beginning of the function...
function [binary_array_e1 , binary_array_e2 ] = croiser(binary_array_p1,binary_array_p2,alpha )
binary_array_e1=[];
binary_array_e2=[];
% ...
end
and then just check the outcome whenever you need to do it, for example:
[binary_array_e1,binary_array_e2] = croiser(binary_array_p1,binary_array_p2,alpha);
if (isempty(binary_array_e1))
% do something 1...
elseif (isempty(binary_array_e2))
% do something 2...
else
% do something 3...
end
Of course, in order to check the outcome, both variables must be returned and evaluated. But if you are returning two empty arrays in one case and two non-empty arrays in the other case, you could also check only one array:
if (isempty(binary_array_e1))
% do something...
else
% do something else...
end
Anyway... there are so many ways to obtain the same result. For example, you could also return a 'logical' variable that tells you immediately if your arrays have been filled with something or not, or you could return a 'struct' filled with your data in order to make everything more compact (I can elaborate on these solutions if you want). It's up to you but I see nothing wrong in your approach!
Yes, that should be fine. You can later check if the output is an empty array using the function isempty
So I am creating an app to work out a value based on a series of variables. The variables are:
Gender
Age
Weight
Creatinine
Here's what the app looks like:
In order to simplify the process somewhat I decided to make the gender selection a dropdown menu, this has caused me some issues since I have it setup like so:
And the maths associated with the button looks like so:
function CalculateButtonPushed(app, event)
gender = app.PatientGenderDropDown.Value ;
age = app.PatientAgeEditField.Value ;
weight = app.LeanBodyWeightEditField.Value ;
serum = app.SerumCreatinineEditField.Value ;
final = (gender*(age)*weight) / (serum) ;
app.ResultEditField.Value = final ;
end
end
Running this gives the following error:
Error using
matlab.ui.control.internal.model.AbstractNumericComponent/set.Value
(line 104) 'Value' must be numeric, such as 10.
As far as I am aware, the values I input into ItemsData are numeric values. Have I missed something or is there a better way to do this?
If you put a breakpoint in the offending file on the appropriate line (by running the below code),
dbstop in uicomponents\+matlab\+ui\+control\+internal\+model\AbstractNumericComponent.m at 87
you could see the following in your workspace, after clicking the button:
There are two separate problems here, both of which can be identified by looking at the newValue validation code (appearing in AbstractNumericComponent.m):
% newValue should be a numeric value.
% NaN, Inf, empty are not accepted
validateattributes(...
newValue, ...
{'numeric'}, ...
{'scalar', 'real', 'nonempty'} ...
);
Here are the issues:
The new value is a vector of NaN.
The reason for this is in this line:
final = (gender*(age)*weight) / (serum) ;
where serum has a value of 0 - so this is the first thing you should take care of.
The new value is a vector of NaN.
This is a separate problem, since the set.Value function (which is implicitly called when you assign something into the Value field), is expecting a scalar. This happens because gender is a 1x4 char array - so it's treated as 4 separate numbers (i.e. the assumption about ItemsData being a numeric is incorrect). The simplest solution in this case would be to str2double it before use. Alternatively, store the data in another location
(such as a private attribute of the figure), making sure it's numeric.
Is it possible to refer back to/access the names of variables (say nx1 arrays) that make up a matrix? I wish to access them to insert there names into a plot or figure (as a text) that I have created. Here is an example:
A = [supdamp, clgvlv,redamp,extfanstat,htgvlv,occupied,supfanspd]
%lots of code here but not changing A, just using A(:,:)'s
%drawn figure
text(1,1,'supdamp')
...
text(1,n,'supfanspd')
I have failed in an attempt create a string named a with their names in so that I could loop through a(i,1), then use something like text(1,n,'a(i,1)')
Depending on your problem, it might make sense to use structures with dynamical field names.
Especially if your data in the array have some meaning other than just entries of a matrix in linear algebra sense.
# name your variables so that your grandma could understand what they store
A.('supdamp') = supdamp
A.('clgvlv') = clgvlv
...
fieldsOfA = fieldnames(a)
for n = 1 : numel(fieldsOfA )
text(1, n, fieldsOfA{n})
end
Can anyone tell me how to compare this for loop array value pp1 with the single value of pp. If the value of pp is present in pp1 then it must show 1 or must show 0. I'm getting 1 only the last value of pp1. The code is:
[pp,pf1]=pitchauto(x,fs);
for ix=1:2
V='.wav';
ie=num2str(ix);
Stc=strcat(ie,V);
[x1,fs1]=wavread(Stc);
figure,plot(x1);
title('Test Audio');
[pp1,pf1]=pitchauto(x1,fs1);
end
if (pp==pp1)
msgbox('Matching');
else
msgbox('Not Matching');
end
Kindly do reply with the correct answers.
You calculate a value for pp1 each time, do nothing with it, then let the next loop iteration overwrite it. To make use of it, either put the test inside the loop:
for ix=1:2
V='.wav';
ie=num2str(ix);
Stc=strcat(ie,V);
[x1,fs1]=wavread(Stc);
figure,plot(x1);
title('Test Audio');
[pp1,pf1]=pitchauto(x1,fs1);
if (pp==pp1)
msgbox('Matching', num2str(ix)); % show the index number as msgbox title
else
msgbox('Not Matching', num2str(ix));
end
end
or collect the values of pp1 in an array to test afterwards:
for ix=1:2
V='.wav';
ie=num2str(ix);
Stc=strcat(ie,V);
[x1,fs1]=wavread(Stc);
figure,plot(x1);
title('Test Audio');
[pp1(ix),pf1]=pitchauto(x1,fs1); % assuming pitchauto returns a scalar
end
matchidx = (pp == pp1);
if any(matchidx)
msgbox(strcat('Matching indices: ', num2str(find(matchidx))));
else
msgbox('Not Matching');
end
If the values aren't scalar, then this approach is a bit more difficult - you could still use a matrix to collect equal-sized vectors, or a cell array to collect anything - but it's probably easier to stick with the first approach in that case.