I wanted to run this line but unfortunately it throws an error. Any ideas?
Undefined function or variable mr.
Error in Playground (line 23)
X = min(mr);
j = 1;
for i = 1:(resolution1+1)
line(i) = m(a(1))*ab(i)+c;
end
for i = 1:(resolution1)
if or(or(line(i)>ab_y(i) & line(i+1)<ab_y1(i+1),line(i)<ab_y1(i)& line(i+1)>ab_y1(i+1)),line(i)==ab_y1(i))
mr(j) = ab1(i);
rk(j) = ab_y1(j);
j = j+1;
end
end
X = min(mr);
Y = max(mr);
Your condition:
or(or(line(i)>ab_y(i) & line(i+1)<ab_y1(i+1),line(i)<ab_y1(i)& line(i+1)>ab_y1(i+1)),line(i)==ab_y1(i))
returns always false, so the statements inside
mr(j)=ab1(i); rk(j)=ab_y1(j);
are never executed. Therefore variable mr does not exist.
Add an mr = []; statement before the loop to initialize the variable (and also revise your condition why it returns always false).
Related
First, sorry for the bad title - I'm new to OO programming - basically I'd like to understand how Matlab works with oop classes.
Before I ask my question, here is a basic example of what I want to do:
I have two houses and some data about them and I got the idea, to work with oop classes. Here is my .m file.
classdef building
properties
hohe = 0;
lange = 0;
breite = 0;
xabstandsolar = 0;
yabstandsolar = 0;
end
methods
function obj = building(hohe, lange, breite, xabstandsolar, yabstandsolar)
obj.hohe = hohe;
obj.lange = lange;
obj.breite = breite;
obj.xabstandsolar = xabstandsolar;
obj.yabstandsolar = yabstandsolar;
end
function hohenwinkel(h)
h = h
d = sqrt(obj.xabstandsolar^2 + yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end
end
end
I filled it with some data - for example
>>H1 = building(10,8,6,14,8)
>>H2 = building(18,8,6,14,0)
And now I want to calculate "gamma_v" (as an 1x2 array) for each building. Any ideas, how I can archive this?
Edit:
I want to create gamma_v (as an array) automatically for all objects in the class "building". There will be a lot more "houses" in the final script.
Your hohenwinkel method needs to accept two input arguments. The first argument for non-static methods is always the object itself (unlike C++, you'll have to explicitly list it as an input argument) and the second input will be your h variable. You'll also want to actually return the gamma_v value using an output argument for your method.
function gamma_v = hohenwinkel(obj, h)
d = sqrt(obj.xabstandsolar^2 + obj.yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end
Then you can invoke this method on each building to get the value
gamma_v1 = hohenwinkel(H1);
gamma_v2 = hohenwinkel(H2);
If you want to have an array of buildings, you can create that array
houses = [building(10,8,6,14,8), building(18,8,6,14,0)];
gamma_v = hohenwinkel(houses);
and then construct your hohenwinkel function to operate on each one and return the result
function gamma_v = hohenwinkel(obj, h)
if numel(obj) > 1
% Compute hohenwinkel for each one
gamma_v = arrayfun(#(x)hohenwinkel(x, h), obj);
return
end
d = sqrt(obj.xabstandsolar^2 + obj.yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end
there is some tricky solution (and its not recommended)(#Suever solution is better)
you should create a handle class
classdef gvclass<handle
properties
gvarr=[];
end
methods
function setgvarr(obj,value)
obj.gvarr=[obj.gvarr,value];
end
end
end
then use this class in your building class
classdef building<handle
properties
gv
hohe = 0;
lange = 0;
breite = 0;
xabstandsolar = 0;
yabstandsolar = 0;
end
methods
function obj = building(hohe, lange, breite, xabstandsolar, yabstandsolar,handle_of_your_gv_class,h)
obj.hohe = hohe;
obj.lange = lange;
obj.breite = breite;
obj.xabstandsolar = xabstandsolar;
obj.yabstandsolar = yabstandsolar;
obj.gv=handle_of_your_gv_class;
obj.hohenwinkel(h);
end
function hohenwinkel(obj,h)
d = sqrt(obj.xabstandsolar^2 + yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
obj.gv.setgvarr(gamma_v);
end
end
end
finally before creating any building you should create an object of gv class and pass it to the building constructor,
Egv=gvclass();
H1 = building(10,8,6,14,8,Egv,2)
H2 = building(18,8,6,14,0,Egv,3)
and to access gv array:
Egv.gvarr
you should do more effort on this issue to debug possible errors.
In simulink, I made some model using "MATLAB function"block
but I met error message here.
here is code and error message.
function [VTAS,postVTAS]=fcn(mode,initialVTAS,a,t,preVTAS)
if mode == 1
VTAS = initialVTAS + (a * t) ;
postVTAS = VTAS;
elseif mode == 2
datasize = length(preVTAS);
lastvalue = preVTAS(datasize);
VTAS = lastvalue + 0;
postVTAS = VTAS;
end
end
Output argument 'VTAS' is not assigned on some execution paths.
Function 'MATLAB Function' (#36.25.28), line 1, column 26:
"fcn"
Launch diagnostic report.
I think there is no problem about output "VTAS"
please teach me what is a problems.
As the compiler tells you, under some circumstances there is no output value assigned to VTAS. The reason is that you only assign values to that output if mode is 1 or 2. The compiler doesn't know what values are feasible for mode. To remedy this, you need to make sure that VTAS is assigned under any and all circumstances.
This could be accomplished by, e.g. adding an else construct, like so:
function [VTAS,postVTAS]=fcn(mode,initialVTAS,a,t,preVTAS)
if mode == 1
VTAS = initialVTAS + (a * t) ;
postVTAS = VTAS;
elseif mode == 2
datasize = length(preVTAS);
lastvalue = preVTAS(datasize);
VTAS = lastvalue + 0;
postVTAS = VTAS;
else
VTAS = NaN;
postVTAS = NaN;
end
end
Edit:
Additionally, it would be good practice for the else case to throw an error. This would be helpful for debugging.
As a minor note, for every case, postVTAS is equal to VTAS, so essentially it is superfluous to return both from the function.
I'm new to Matlab and now learning the basic grammar.
I've written the file GetBin.m:
function res = GetBin(num_bin, bin, val)
if val >= bin(num_bin - 1)
res = num_bin;
else
for i = (num_bin - 1) : 1
if val < bin(i)
res = i;
end
end
end
and I call it with:
num_bin = 5;
bin = [48.4,96.8,145.2,193.6]; % bin stands for the intermediate borders, so there are 5 bins
fea_val = GetBin(num_bin,bin,fea(1,1)) % fea is a pre-defined 280x4096 matrix
It returns error:
Error in GetBin (line 2)
if val >= bin(num_bin - 1)
Output argument "res" (and maybe others) not assigned during call to
"/Users/mac/Documents/MATLAB/GetBin.m>GetBin".
Could anybody tell me what's wrong here? Thanks.
You need to ensure that every possible path through your code assigns a value to res.
In your case, it looks like that's not the case, because you have a loop:
for i = (num_bins-1) : 1
...
end
That loop will never iterate (so it will never assign a value to res). You need to explicitly specify that it's a decrementing loop:
for i = (num_bins-1) : -1 : 1
...
end
For more info, see the documentation on the colon operator.
for i = (num_bin - 1) : -1 : 1
I am new in matlab I am trying to define a function and I keep getting this error
" input argument "ip" is undefined.
Error in ==> edge_mapping at 2
size_ip = size(ip(:,:,1)); "
here is my code
function[op1,op2,op3] = edge_mapping(ip)
size_ip = size(ip(:,:,1));
s=size_ip(1);
op1= cat(3,zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s));
op2= cat(3,zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s));
op3= cat(3,zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s),zeros(s));
for i = 1 : 10
op1(:,:,i)=edge(ip(:,:,i),'sobel');
op2(:,:,i)=edge(ip(:,:,i),'prewitt');
op3(:,:,i)=edge(ip(:,:,i),'canny');
end
function [op1, op2, op3] = edge_mapping(ip)
op1 = zeros(size(ip));
op2 = zeros(size(ip));
op3 = zeros(size(ip));
for i = 1 : size(ip, 3)
op1(:,:,i)=edge(ip(:,:,i),'sobel');
op2(:,:,i)=edge(ip(:,:,i),'prewitt');
op3(:,:,i)=edge(ip(:,:,i),'canny');
end
return
But I think it's better to write a simple function:
function op = edge_mapping(ip, edge_mode)
op = zeros(size(ip));
for i = 1 : size(ip, 3)
op(:,:,i)=edge(ip(:,:,i), edge_mode);
end
return
and then call it:
op_sobel = edge_mapping(ip, 'sobel');
op_prewitt = edge_mapping(ip, 'prewitt');
op_canny = edge_mapping(ip, 'canny');
This code is a function. It has to be save as m-file and run from MATLAB command line, script or another function as
[op1,op2,op3] = edge_mapping(ip);
where arguments ip, op1, op2, and op3 can have different names.
Make sure you have space after function keyword.
To avoid this error you can assign a default value for the input argument if it's undefined (not exist in the function's scope):
if ~exist(ip, 'var')
ip = []; %# or other default value
end
Is it somehow possible to concatenate two matlab structures recursively without iterating over all leaves of one of the structures.
For instance
x.a=1;
x.b.c=2;
y.b.d=3;
y.a = 4 ;
would result in the following
res = mergeStructs(x,y)
res.a=4
res.b.c=2
res.b.d=3
The following function works for your particular example. There will be things it doesn't consider, so let me know if there are other cases you want it to work for and I can update.
function res = mergeStructs(x,y)
if isstruct(x) && isstruct(y)
res = x;
names = fieldnames(y);
for fnum = 1:numel(names)
if isfield(x,names{fnum})
res.(names{fnum}) = mergeStructs(x.(names{fnum}),y.(names{fnum}));
else
res.(names{fnum}) = y.(names{fnum});
end
end
else
res = y;
end
Then res = mergeStructs(x,y); gives:
>> res.a
ans =
4
>> res.b
ans =
c: 2
d: 3
as you require.
EDIT: I added isstruct(x) && to the first line. The old version worked fine because isfield(x,n) returns 0 if ~isstruct(x), but the new version is slightly faster if y is a big struct and ~isstruct(x).