I have problem with the following code:
.
.
.
a=zeros(1000,ctimes);
a1=zeros(1000,ctimes);
hold all
for i=num1:num2;
colors=Lines(i);
switch phantom
case 1
path=['E:\filename\'];
path1=['E:\filename2\'];
n=['S',num2str(emt),'_',num2str(i),'.m'];
d=load([path,name]);
a(:,i)=complex(d(:,2),d(:,3)));
n1=['S',num2str(emt),'_',num2str(i),'.m'];
d1=load([path1,name1]);
a1(:,i)=complex(d1(:,2),d1(:,3)));
the problem is that a(:,i) can not be defined. while there is no problem or with complex(d1(:,2),d1(:,3))) , can any expert body help me plz?!
thank you ...
Are you sure you are forming your file name correctly? You are doing something to create a variable n, but using a variable name when you form the path. Here are some recommended debugging steps:
1) make sure the file path is formed correctly:
filePath = fullfile(path, name);
disp(filePath);
The fullfile function concatenates elements of a file path & name, and takes care of using the right file path separator (good for portable code, stops you having to remember to add a / or \ to the end of a file path, etc).
2) check that d is loaded correctly:
clear d;
d = load(filePath);
disp(size(d));
3) check the size of the complex quantity you compute before assigning it to a(:,i):
temp = complex(d(:,2), d(:,3));
disp(size(temp));
By the time you have done these things, you should have found your problem (the dimensions of temp should be [1000 1] to match the size of a(:,i), of course).
As an aside, you should avoid using i as a variable name, especially when you are using complex numbers, since its built-in value is sqrt(-1). Thus, c = a + i * b; would create a complex number (a,b) and put it into c - until you change the meaning of i. A simple solution is to use ii. The same is true for j, by the way. It is one of the unfortunate design decisions in Matlab that you can overwrite built in values like that...
Related
I would like to add the sums of 5 one-column arrays in Matlab. The catch is that depending on previous inputs, any of these arrays may or may not exist, thus throwing an error when I try to add the sums of these arrays for post-processing.
After doing some digging I found the following function which I can use to return a logical statement if a certain variable exists in the workspace:
exist('my_variable','var') == 1
I'm not sure this helps me in this case though - Currently the line in which I add the sums of the various arrays looks as follows:
tot_deviation = sum(var1) + sum(var2) + sum(var3) + sum(var4) + sum(var4);
Is there a short way to add only the sums of the existing arrays without excessive loops?
Any help would be appreciated!
You can use if statements:
if ~exist('var1','var'), var1 = 0;end
if ~exist('var2','var'), var2 = 0;end
if ~exist('var3','var'), var3 = 0;end
if ~exist('var4','var'), var4 = 0;end
tot_deviation = sum(var1) + sum(var2) + sum(var3) + sum(var4) + sum(var4);
To my knowledge there is no quick way to do this in matlab. It seems to me that, depending on the structure of your code, you have the following alternatives:
1- Initialize all your variables to column arrays of zeros with something like
var = zeros(nbLines, 1);
2- Put all your columns vectors side to side in a single array and the use tot_deviation = sum(sum(MyArray)); which will work no matter how many columns and lines there is in the array.
3- If you pass your variables to a function you can check the number of inputs arguments inside the function using 'nargin' and then only proceed to sum the right number of variables.
I would recommend using the second method for it seem to me that it is the one that allows you to take the most advantage of matlab's array system which good.
The most robust solution is to initialise all of your variables to 0 at the top of the function. Then there is no chance they don't exist, and they influence the summation correctly.
Alternatively...
You could (read: shouldn't) use a really nasty eval trick here for flexibility...
vars = {'var1','var2','var3','var4'};
tot = 0;
for ii = 1:numel(vars)
if exist(vars{ii}, 'var')
tot = tot + eval(var);
end
end
I say it's "nasty" because eval should be avoided (read the linked blog). The check on the variable name existence mitigates some of the strife, but it's still not ideal.
As suggested in the MathWorks blog on evading eval, a better option would be a struct with dynamic field names. You could use almost the same syntax as above, but replace the if statement with
if isfield( myStruct, vars{ii} )
tot = tot + myStruct.(vars{ii});
end
This will avoid dynamically named variables and keep your workspace clean!
How to call an m file from another m file in MATLAB without add its folder path?
I don't want to add its folder via
addpath(genpath(''))
Similar to the functionality of MATLAB's built-in run for scripts, you can cd into the secondary path, execute your function, and then return to the previous directory.
A small example:
% testcode.m
function [output] = testcode(fullfunctionpath, A, B)
[pathname, functionName] = fileparts(fullfunctionpath);
olddir = cd(pathname);
output = feval(functionName, A, B);
cd(olddir);
end
% .\test\testing.m
function [output] = testing(A, B)
output = A + B;
end
With the call:
C = testcode('C:\testcode-matlab\test\testing.m', 1, 2);
Will return
C =
3
Note that this approach does not have error handling nor does it check for duplicates that already exist in your path definition. If the called function is not present in the target folder but does exist in the path, the function in MATLAB's path will still be executed. See: Function Precedence Order for more information.
All visibility rules for functions are based on Folders. If you want to have different visibilities you have to place your functions in different folders.
Typically, avoiding duplicate function names and just adding all source files to your search path is what works. To avoid duplicate function names you may want to take a look at packages.
I have many .txt files like these: "u1.txt", "i3.txt", "p10.txt"... How to load all of these files to matlab, to variables like these: "u1", "u2"... "p1"... Here is my code:
clc, clear all
%% loading data
for j=0:3
switch j
case 0
variable='i';
case 1
variable='u';
case 2
variable='p';
case 3
variable='q';
end
for i=0:15
name = strcat(variable, int2str(i), '.txt')
fid=fopen(name,'r');
data=textscan(fid,'%*s%*s%s%s%s%*s','HeaderLines',10,'CollectOutput',1);
fclose(fid);
data=strrep(data{1},',','.');
data=cellfun(#str2num, data);
end
end
Problem is with variable data - how to change this variable to: "u1", "u2"... "p1"... after every loop?
You could use the variable names u1 u2 etc.. but I would strongly recommend not to do so. Then these consecutive variables u1 to u15 are totally individual variables and basically matlab can not iterate over these variables. For this purpose, I would use a struct which contains cell arrays. Use this line to assign:
allData.(variable){i}=data
And to get your data, instead of u1 use allData.u{1}. These are some more characters to write, but having such structured data results in much simpler code when you use the data.
//Code:
for j=0:3
switch j
case 0
variable='i';
case 1
variable='u';
case 2
variable='p';
case 3
variable='q';
end
for i=0:15
name = strcat(variable, int2str(i), '.txt')
fid=fopen(name,'r');
data=textscan(fid,'%*s%*s%s%s%s%*s','HeaderLines',10,'CollectOutput',1);
fclose(fid);
data=strrep(data{1},',','.');
data=cellfun(#str2num, data);
allData.(variable){i}=data;
end
end
Use eval.
For example:
x = input('Enter the name of the new variable: ','s');
eval([x,'=0:4;']);
In your case:
variablename = strcat(variable,int2str(i));
eval([variablename,'=cellfun(#str2num,',variablename,')'];
This is a good read: Creating variables on the run
You could use eval to do this:
eval([name '=textscan(fid,'%*s%*s%s%s%s%*s','HeaderLines',10,'CollectOutput',1);']);
I think that syntax is correct but I'm not sure. You might have to play around with it a bit to get it to work, which is a huge drawback to using eval in the first place. Not to mention the syntax parser can't work with it, making it more difficult to debug.
My recommendation would be to utilize MATLAB's capability to use dynamic fieldnames.
data.(name)=textscan(fid,'%*s%*s%s%s%s%*s','HeaderLines',10,'CollectOutput',1);
Much cleaner and much easier to debug.
My other recommendation is that you evaluate why you need to utilize this naming scheme in the first place. It will be much easier to create an array (numeric or cell) and use that numeric ID as an index rather than include it with the variable name.
I want to create a structure with a variable name in a matlab script. The idea is to extract a part of an input string filled by the user and to create a structure with this name. For example:
CompleteCaseName = input('s');
USER WRITES '2013-06-12_test001_blabla';
CompleteCaseName = '2013-06-12_test001_blabla'
casename(12:18) = struct('x','y','z');
In this example, casename(12:18) gives me the result test001.
I would like to do this to allow me to compare easily two cases by importing the results of each case successively. So I could write, for instance :
plot(test001.x,test001.y,test002.x,test002.y);
The problem is that the line casename(12:18) = struct('x','y','z'); is invalid for Matlab because it makes me change a string to a struct. All the examples I find with struct are based on a definition like
S = struct('x','y','z');
And I can't find a way to make a dynamical name for S based on a string.
I hope someone understood what I write :) I checked on the FAQ and with Google but I wasn't able to find the same problem.
Use a structure with a dynamic field name.
For example,
mydata.(casename(12:18)) = struct;
will give you a struct mydata with a field test001.
You can then later add your x, y, z fields to this.
You can use the fields later either by mydata.test001.x, or by mydata.(casename(12:18)).x.
If at all possible, try to stay away from using eval, as another answer suggests. It makes things very difficult to debug, and the example given there, which directly evals user input:
eval('%s = struct(''x'',''y'',''z'');',casename(12:18));
is even a security risk - what happens if the user types in a string where the selected characters are system(''rm -r /''); a? Something bad, that's what.
As I already commented, the best case scenario is when all your x and y vectors have same length. In this case you can store all data from the different files into 2 matrices and call plot(x,y) to plot each column as a series.
Alternatively, you can use a cell array such that:
c = cell(2,nufiles);
for ii = 1:numfiles
c{1,ii} = import x data from file ii
c{2,ii} = import y data from file ii
end
plot(c{:})
A structure, on the other hand
s.('test001').x = ...
s.('test001').y = ...
Use eval:
eval(sprintf('%s = struct(''x'',''y'',''z'');',casename(12:18)));
Edit: apologies, forgot the sprintf.
I am trying to create a function call graph for around 500 matlab src files. I am unable to find any tools which could help me do the same for multiple src files.
Is anyone familiar with any tools or plugins?
In case any such tools are not available, any suggestions on reading 6000 lines of matlab code
without documentation is welcome.
Let me suggest M2HTML, a tool to automatically generate HTML documentation of your MATLAB m-files. Among its feature list:
Finds dependencies between functions and generates a dependency graph (using the dot tool of GraphViz)
Automatic cross-referencing of functions and subfunctions with their definition in the source code
Check out this demo page to see an example of the output of this tool.
I recommend looking into using the depfun function to construct a call graph. See http://www.mathworks.com/help/techdoc/ref/depfun.html for more information.
In particular, I've found that calling depfun with the '-toponly' argument, then iterating over the results, is an excellent way to construct a call graph by hand. Unfortunately, I no longer have access to any of the code that I've written using this.
I take it you mean you want to see exactly how your code is running - what functions call what subfunctions, when, and how long those run for?
Take a look at the MATLAB Code Profiler. Execute your code as follows:
>> profile on -history; MyCode; profile viewer
>> p = profile('info');
p contains the function history, From that same help page I linked above:
The history data describes the sequence of functions entered and exited during execution. The profile command returns history data in the FunctionHistory field of the structure it returns. The history data is a 2-by-n array. The first row contains Boolean values, where 0 means entrance into a function and 1 means exit from a function. The second row identifies the function being entered or exited by its index in the FunctionTable field. This example [below] reads the history data and displays it in the MATLAB Command Window.
profile on -history
plot(magic(4));
p = profile('info');
for n = 1:size(p.FunctionHistory,2)
if p.FunctionHistory(1,n)==0
str = 'entering function: ';
else
str = 'exiting function: ';
end
disp([str p.FunctionTable(p.FunctionHistory(2,n)).FunctionName])
end
You don't necessarily need to display the entrance and exit calls like the above example; just looking at p.FunctionTable and p.FunctionHistory will suffice to show when code enters and exits functions.
There are already a lot of answers to this question.
However, because I liked the question, and I love to procrastinate, here is my take at answering this (It is close to the approach presented by Dang Khoa, but different enough to be posted, in my opinion):
The idea is to run the profile function, along with a digraph to represent the data.
profile on
Main % Code to be analized
p = profile('info');
Now p is a structure. In particular, it contains the field FunctionTable, which is a structure array, where each structure contains information about one of the calls during the execution of Main.m. To keep only the functions, we will have to check, for each element in FunctionTable, if it is a function, i.e. if p.FunctionTable(ii).Type is 'M-function'
In order to represent the information, let's use a MATLAB's digraph object:
N = numel(p.FunctionTable);
G = digraph;
G = addnode(G,N);
nlabels = {};
for ii = 1:N
Children = p.FunctionTable(ii).Children;
if ~isempty(Children)
for jj = 1:numel(Children)
G = addedge(G,ii,Children(jj).Index);
end
end
end
Count = 1;
for ii=1:N
if ~strcmp(p.FunctionTable(ii).Type,'M-function') % Keep only the functions
G = rmnode(G,Count);
else
Nchars = min(length(p.FunctionTable(ii).FunctionName),10);
nlabels{Count} = p.FunctionTable(ii).FunctionName(1:Nchars);
Count = Count + 1;
end
end
plot(G,'NodeLabel',nlabels,'layout','layered')
G is a directed graph, where node #i refers to the i-th element in the structure array p.FunctionTable where an edge connects node #i to node #j if the function represented by node #i is a parent to the one represented by node #j.
The plot is pretty ugly when applied to my big program but it might be nicer for smaller functions:
Zooming in on a subpart of the graph:
I agree with the m2html answer, I just wanted to say the following the example from the m2html/mdot documentation is good:
mdot('m2html.mat','m2html.dot');
!dot -Tps m2html.dot -o m2html.ps
!neato -Tps m2html.dot -o m2html.ps
But I had better luck with exporting to pdf:
mdot('m2html.mat','m2html.dot');
!dot -Tpdf m2html.dot -o m2html.pdf
Also, before you try the above commands you must issue something like the following:
m2html('mfiles','..\some\dir\with\code\','htmldir','doc_dir','graph','on')
I found the m2html very helpful (in combination with the Graphviz software). However, in my case I wanted to create documentation of a program included in a folder but ignoring some subfolders and .m files. I found that, by adding to the m2html call the "ignoreddir" flag, one can make the program ignore some subfolders. However, I didn't find an analogue flag for ignoring .m files (neither does the "ignoreddir" flag do the job). As a workaround, adding the following line after line 1306 in the m2html.m file allows for using the "ignoreddir" flag for ignoring .m files as well:
d = {d{~ismember(d,{ignoredDir{:}})}};
So, for instance, for generating html documentation of a program included in folder "program_folder" but ignoring "subfolder_1" subfolder and "test.m" file, one should execute something like this:
m2html( 'mfiles', 'program_folder', ... % set program folder
'save', 'on', ... % provide the m2html.mat
'htmldir', './doc', ... % set doc folder
'graph', 'on', ... % produce the graph.dot file to be used for the visualization, for example, as a flux/block diagram
'recursive', 'on', ... % consider also all the subfolders inside the program folders
'global', 'on', ... % link also calls between functions in different folders, i.e., do not link only the calls for the functions which are in the same folder
'ignoreddir', { 'subfolder_1' 'test.m' } ); % ignore the following folders/files
Please note that all subfolders with name "subfolder_1" and all files with name "test.m" inside the "program_folder" will be ignored.