I'm new to MATLAB, and I can't manage to make my function work in order to save my data into a .mat file.
The input:
A structure, with 5 fields:
data: 3D matrix of 19x1000x143
labels: 1x143 matrix with 1 or -1 in it
subject_number: an integer
sampling_rate: an integer, 500 Hz
channel_names: 1x19 matrix with text in it
name: a string for the name of the file
clean: a matrix 1x143 with 1 or 0 in it.
The idea is to save only the clean data, marked as 1 in the clean matrix.
If clean(i) is equal to 1:
save data(:,:,i) and labels(:,i)
This is the code I've tried to implement in the saving.m file:
function saving(EEG_struct, clean, name)
subject_number = EEG_struct.subject_number;
fs = EEG_struct.sampling_rate;
chan_names = EEG_struct.channel_names;
nb_epoch = size(EEG_struct.data, 3);
for j=1:nb_epoch
if clean(j) == 1
% Keep the epoch and label
data = cat(3, data, EEG_struct.data(:,:,j));
labels = cat(2, labels, EEG_struct.labels(:,j));
end
end
save(name, data, labels, subject_number, fs, chan_names)
As you can see, I would like to save the data as a structure with the same shape as the EEG_struct input.
Moreover, I would like to use a parfor instead of a for, but it raised me an error I didn't quite get:
An UndefinedFunction error was thrown on the workers for 'data'. This might be because the file containing 'data' is not accessible on the workers. Use addAttachedFiles(pool, files) to specify the required files to be attached. See the documentation for 'parallel.Pool/addAttachedFiles' for more details. Caused by: Undefined function or variable 'data'.
Thanks for the help !
You can use your clean variable as a logical index and parse out your data and labels at once. So there is no need for a loop.
Also the save command needs the "names" of the vars to save not the variables themselves. So I just put ' ' around each one.
function saving(EEG_struct, clean, name)
subject_number = EEG_struct.subject_number;
fs = EEG_struct.sampling_rate;
chan_names = EEG_struct.channel_names;
nb_epoch = size(EEG_struct.data, 3);
%No need for a loop at all
data = EEG_struct.data(:,:,logical(clean));
labels = EEG_struct.labels(logical(clean)); %This is a 1xN so I removed the extra colon operator
save(name, 'data', 'labels', 'subject_number', 'fs', 'chan_names');
EDIT:
Per you comment if you want to just leave everything in the structure. I gave you 2 options for how to save it.
function saving(EEG_struct, clean, name)
%Crop out ~clead data
EEG_struct.data = EEG_struct.data(:,:,logical(clean));
EEG_struct.labels = EEG_struct.labels(logical(clean)); %This is a 1xN so I removed the extra colon operator
% Option 1
save(name, 'EEG_struct');
% Option2
save(name, '-struct', 'EEG_struct');
Option 1 will directly save the struct to the MAT file. So if you were to load the data back like this:
test = load(name);
test =
EEG_struct: [1x1 struct]
You would get your structure placed inside another structure ... which might not be ideal or require an extra line to de-nest it. On the other hand just loading the MAT file with no outputs load(name) would put EEG_struct into your current workspace. But if in a function then it sort of springs into existence without every being declared which makes code a bit harder to follow.
Option 2 uses the '-struct' option which breaks out each field automatically into separate vars in the MAT file. So loading like this:
EEG_struct = load(name);
Will put all the fields back together again. To me at least this looks cleaner when done within a function but is probably just my preference
So comment out which ever you prefer. Also, not I did not include clean in the save. You could either append it to the MAT or add it to your structure.
To get a structure the same as EEG_struct but with only the data/labels corresponding with the clean variable, you can simply make a copy of the existing structure and remove the rows where clean=0
function saving(EEG_struct, clean, name)
newstruct = EEG_struct;
newstruct.data(:,:,logical(~clean)) = '';
newstruct.labels(logical(~clean)) = '';
save(name,'newstruct');
Related
So I have an iterative loop that extracts data from .csv files in MATLAB's active folder and plots it. I would like to take it one step further and run the script on two folders, each with their own .csv files.
One folder is called stress and the other strain. As the name implies, they contain .csv files for stress and strain data for several samples, each of which is called E3-01, E3-02, E3-03, etc. In other words, both folders have the same number of files and the same names.
The way I see it, the process would have the following steps:
Look in the stress folder, look inside file E3-01, extract the data in the column labelled Stress
Look in the strain folder, look inside file E3-01, extract the data in the column labelled Strain
Combine the data together for sample E3-01 and plot it
Repeat steps 1-3 for all files in the folders
Like I said, I already have a script that can find the right column and extract the data. What I'm not sure about is how to tell MATLAB to alternate the folder that the script is being run on.
Instead of a script, would a function be better? Something that accepts 4 inputs: the names of the two folders and the columns to extract?
EDIT: Apologies, here's the code I have so far:
clearvars;
files = dir('*.csv');
prompt = {'Plot name:','x label:','y label:','x values:','y values:','Points to eliminate:'};
dlg_title = 'Input';
num_lines = 1;
defaultans = {'Title','x label','y label','Surface component 1.avg(epsY) [True strain]','Stress','0'};
answer = inputdlg(prompt,dlg_title,num_lines,defaultans);
name_plot = answer{1};
x_label = answer{2};
y_label = answer{3};
x_col = answer{4};
y_col = answer{5};
des_cols = {y_col,x_col};
smallest_n = 100000;
points_elim = answer{6};
avg_x_values = [];
avg_y_values = [];
for file = files'
M=xlsread(file.name);
[row,col]=size(M);
if smallest_n > row
smallest_n = row;
end
end
smallest_n=smallest_n-points_elim;
avg_x_values = zeros(smallest_n,size(files,1));
avg_y_values = zeros(smallest_n,size(files,1));
hold on;
set(groot, 'DefaultLegendInterpreter', 'none');
set(gca,'FontSize',20);
ii = 0;
for file = files'
ii = ii + 1;
[n,s,r] = xlsread(file.name);
colhdrs = s(1,:);
[row, col] = find(strcmpi(s,x_col));
x_values = n(1:end-points_elim,col);
[row, col] = find(strcmpi(s,y_col));
y_values = n(1:end-points_elim,col);
plot(x_values,y_values,'DisplayName',s{1,1});
avg_x_values(:,ii)=x_values(1:smallest_n);
avg_y_values(:,ii)=y_values(1:smallest_n);
end
ylabel({y_label});
xlabel({x_label});
title({name_plot});
colormap(gray);
hold off;
avg_x_values = mean(avg_x_values,2);
avg_y_values = mean(avg_y_values,2);
plot(avg_x_values,avg_y_values);
set(gca,'FontSize',20);
ylabel({y_label});
xlabel({x_label});
title({name_plot});
EDIT 2: #Adriaan I tried to write the following function to get a column from a file:
function [out_col] = getcolumn(col,file)
file = dir(file);
[n,s,r] = xlsread(file.name);
colhdrs = s(1,:);
[row, col] = find(strcmpi(s,col));
out_col = n(1:end,col);
end
but I get the error
Function 'subsindex' is not defined for values of class 'struct'.
Error in getcolumn (line 21)
y = x(:,n);
not sure why.
You can do both, of course, and it depends on preference mainly, provided you're the sole user of the script. If others are going to use it as well, use functions instead, as they can contain a proper help file and calling help functionname will then give you that help.
For instance:
folders1 = dir(../strain/*)
folders2 = dir(../stress/*)
for ii 1 = 1:numel(folders)
operand1 = folders1{ii};
operand2 = folders2{ii};
%... rest of script
%
% Or function:
data = YourFunction(folders1{ii},folders2{ii})
end
So all in all you can use both, although from experience I find functions easier to use in the end, as you just pass parameters and don't need to trawl through the complete code to change the parameters each run.
Additionally you can partition off small parts of your program which do a fix task. If you nest your functions, and finally call just a single function in your scripts, you don't have to look at hundreds of lines of code each time you run the script, but rather can just run a single function (which can also be inside a script or function, ad infinitum).
Finally, a function has its own scope; meaning that any variables that are in that function stay within that function unless you explicitly set them as output (apart from global variables, but those are problematic anyway). This can be a good thing, or a bad thing, depending on the rest of your code. If you function would output ~20 variables for further processing, the function probably should include more steps. It'd be a good thing if you create lots of intermediate variables (I always do), because when the function's finished running, the scope of that function will be removed from memory, saving you clear tmpVar1 tmpVar2 tmpVar3 etc every few lines in your script.
For the script the argument in favour would be that it is easier to debug; you don't need dbstop on error and can step a bit easier through the script, keeping check of all your variables. But, after the debugging has been completed, this argument becomes moot, and thus in general I'd start with writing a script, and once it performs as desired, I rework it to a function at minimal extra effort.
I have a long list of variables in my workspace.
First, I'm finding the potential variables I could be interested in using the who function. Next, I'd like to loop through this list to find the size of each variable, however who outputs only the name of the variables as a string.
How could I use this list to refer to the values of the variables, rather than just the name?
Thank you,
list = who('*time*')
list =
'time'
'time_1'
'time_2'
for i = 1:size(list,1);
len(i,1) = length(list(i))
end
len =
1
1
1
If you want details about the variables, you can use whos instead which will return a struct that contains (among other things) the dimensions (size) and storage size (bytes).
As far as getting the value, you could use eval but this is not recommended and you should instead consider using cell arrays or structs with dynamic field names rather than dynamic variable names.
S = whos('*time*');
for k = 1:numel(S)
disp(S(k).name)
disp(S(k).bytes)
disp(S(k).size)
% The number of elements
len(k) = prod(S(k).size);
% You CAN get the value this way (not recommended)
value = eval(S(k).name);
end
#Suever nicely explained the straightforward way to get this information. As I noted in a comment, I suggest that you take a step back, and don't generate those dynamically named variables to begin with.
You can access structs dynamically, without having to resort to the slow and unsafe eval:
timestruc.field = time;
timestruc.('field1') = time_1;
fname = 'field2';
timestruc.(fname) = time_2;
The above three assignments are all valid for a struct, and so you can address the fields of a single data struct by generating the field strings dynamically. The only constraint is that field names have to be valid variable names, so the first character of the field has to be a letter.
But here's a quick way out of the trap you got yourself into: save your workspace (well, the relevant part) in a .mat file, and read it back in. You can do this in a way that will give you a struct with fields that are exactly your variable names:
time = 1;
time_1 = 2;
time_2 = rand(4);
save('tmp.mat','time*'); % or just save('tmp.mat')
S = load('tmp.mat');
afterwards S will be a struct, each field will correspond to a variable you saved into 'tmp.mat':
>> S
S =
time: 1
time_1: 2
time_2: [4x4 double]
An example writing variables from workspace to csv files:
clear;
% Writing variables of myfile.mat to csv files
load('myfile.mat');
allvars = who;
for i=1:length(allvars)
varname = strjoin(allvars(i));
evalstr = strcat('csvwrite(', char(39), varname, '.csv', char(39), ', ', varname, ')');
eval(evalstr);
end
I have a loop which runs 100 times. In each iteration there is a string, double and a table assigned, and in the next iteration new values are assigned for them. What I want to do is to accumulate these values and after the loop finishes save the total result as result.mat using the matlab save function. I've tried putting them in cell-array but its not working so far, so if anyone could please advise how this can be done.
This is what I did:
results_cell=(100,3);
.
.
.
results_cell(i,1)=stringA;
results_cell(i,2)=TableA;
results_cell(i,3)=DoubleA;
But it gives this error Coversion to Cell from Table is not possible. So I've tried converting TableA to array of Doubles using table2array but I still get this Coversion to Cell from Double is not possible
I think using a structure would be a good way to store your data, since they are of different types and you can assign it meaningful field names for easy reference.
For example, let's call the structure Results. You can initialize it like so.
Results = struct('StringData',[],'TableData',[],'DoubleData',[])
Since you know its dimensions, you can even do this:
N = 100;
Results(N).StringData = [];
Results(N).TableData = [];
Results(N).DoubleData = [];
This automatically create a 1xN structure with 3 fields.
Then in your loop you can assign each field with its associated data like so:
for k = 1:N
Results(k).StringData = String(k);
Results(k).TableData = Table(k);
Results(k).DoubleData = Double(k);
end
where String(k), Table(k) and Double(k) are just generic names for your actual data.
When you're done with the loop you can access any type of data using a single index and the right field name.
In order to save a .mat file, use something like this:
save SomeFileName.mat Results
Which you can load into the workspace as you would with any .mat file:
Eg:
S = load('SomeFileName.mat')
R = S.Results
Hope that helps!
This is a problem I am working on in Matlab.
I am looping through a series of *.ALL files and stripping the field name by a delimiter '.'. The first field is the network, second station name, third location code and fourth component. I pre-allocate my structure based on the number of files (3) I run through which for this example is a 3x3x3 structure that I would like to define as struct(station,loc code,component). You can see these definitions in my code example below.
I would like to loop through the station, loc code, and component and fill their values in the structure. The only problem is for some reason the way I've defined the loop it's actually looping through the files more than once. I only want to loop through each file once and extract the station, comp, and loc code from it and put it inside the structure. Because it's looping through the files more than once it's taken like 10 minutes to fill the structure. This is not very efficient at all. Can someone point out the culprit line for me or tell me what I'm doing incorrectly?
Here's my code below:
close all;
clear;
[files]=dir('*.ALL');
for i = 1:length(files)
fields=textscan(files(i).name, '%s', 'Delimiter', '.');
net{i,1}=fields{1}{:};
sta{i,1}=fields{1}{2};
loc{i,1}=fields{1}{3};
comp{i,1}=fields{1}{4};
data = [];
halfhour(1:2) = struct('data',data);
hour(1:24) = struct('halfhour',halfhour);
day(1:366) = struct('hour',hour);
PSD_YE_DBT(1:length(files),1:length(files),1:length(files)) =
struct('sta','','loc','','comp','','allData',[],'day',day);
end
for s=1:1:length(sta)
for l=1:1:length(loc)
for c=1:1:length(comp)
tempFileName = strcat(net{s},'.',sta{s},'.',loc{l},'.',comp{c},'.','ALL');
fid = fopen(tempFileName);
PSD_YE_DBT(s,l,c).sta = sta{s};
PSD_YE_DBT(s,l,c).loc = loc{l};
PSD_YE_DBT(s,l,c).comp = comp{c};
end
end
end
Example file names for the three files I'm working with are:
XO.GRUT.--.HHE.ALL
XO.GRUT.--.HHN.ALL
XO.GRUT.--.HHZ.ALL
Thanks in advance!
I need to output .mat files for the below data. I need one file to have cell (1,1) to be Mean_RPM_list1, cell (2,1) to be Mean_RPM_list2 etc. And then I need another file to have cell(1,1) to be Mean_Torque_list1 to have cell(1,1).....and so on.
Can anybody shed any light on this for me?
Also if someone knows how to automate me calling the matrices A and B so I could have A = [Mean_rpm1:Mean_rpmMAX], that would also be very helpful.
TIA for any help.
A = [Mean_rpm1 Mean_rpm2 Mean_rpm3 Mean_rpm4 Mean_rpm5 Mean_rpm6 Mean_rpm7 Mean_rpm8 Mean_rpm9 Mean_rpm10 Mean_rpm11 Mean_rpm12];
B = [Mean_torque1 Mean_torque2 Mean_torque3 Mean_torque4 Mean_torque5 Mean_torque6 Mean_torque7 Mean_torque8 Mean_torque9 Mean_torque10 Mean_torque11 Mean_torque12];
plot(A,B,'*')
for i = 1:num_bins;
bin = first + ((i-1)/10);
eval(sprintf('Mean_RPM_list%0.f = A;',bin*10));
eval(sprintf('Mean_Torque_list%0.f = B;',bin*10));
end
First of all this is really bad idea to create a set of variables with names different by numbers. As you can see it's very difficult to deal with such variables, you always have to use eval (or other related) statements.
It's much easier to create a cell array Mean_rpm and access its elements as Mean_rpm{1}, etc.
If the vectors are numeric and have the same size you can also make a 2D/3D array. Then access as Mean_rpm(:,:,1) etc.
Next, to store a cell array to a mat-file you have to create this array in MATLAB. No options (at least for now) to do it by parts in a loop. (But you can do it for numeric vectors and matrices using matfile object.) So why do you need this intermediate Mean_RPM_list variable? Just do Mean_RPM_list{bin*10} = A in your loop.
For your first question, if you already have those variables you have to use eval in a loop. Something like
A = [];
for k=1:K
eval(sprintf('A{k} = [A, Mean_rpm%d];',k));
end
You can also get names for all similar variables and combine them.
varlist = who('Mean_rpm*');
A = cell(1,numel(varlist);
for k = 1:numel(varlist)
eval('A{k} = varlist{k};');
end
Here is one without loop using CELL2FUN:
A=cellfun(#(x)evalin('base',x),varlist,'UniformOutput',0);
You should avoid having all these individual variables around in the first place. Data types like arrays, cell arrays and structure arrays exist to help you with this. If you want each variable to be associated with a name, you can use a structure array. I've made an example below. Instead of assigning a value to Mean_rpm1 like you are doing now, assign it to meanStruct.Mean_rpm1 then save the entire structure.
% as you generate values for each variable, assign them to the
% appropriate field.
meanStruct.Mean_rpm1 = [10:10];
meanStruct.Mean_rpm2 = [12:15];
meanStruct.Mean_rpm3 = [13:20];
meanStruct.Mean_rpm4 = [14];
meanStruct.Mean_rpm5 = [15:18];
meanStruct.Mean_rpm6 = [16:20];
meanStruct.Mean_rpm7 = [17:22];
meanStruct.Mean_rpm8 = [18:22];
meanStruct.Mean_rpm9 = [19:22];
meanStruct.Mean_rpm10 = [20:22];
meanStruct.Mean_rpm11 = [21:22];
meanStruct.Mean_rpm12 = [22:23];
% save the structure array
save('meanValues.mat','meanStruct')
% load and access the structure array
clear all
load('meanValues.mat')
temp = meanStruct.Mean_rpm3