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Matrix product: inv or \ ?
"Why using \ is faster than inv? Is there a numerical reasone?" Yes: because the two division operators use completely differen...

6 years ago | 0

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Answered
The min and max function return incorrect result!
The default display format short displays arrays with five significant figure precision and a common multiplier for all values i...

6 years ago | 1

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For loop problem; could you help?
thi = 0.1:0.1:1; T = 273.15:1:273.15+60; %%% temperature N = numel(T); w = nan(numel(thi),N); % preallocate! Pg = nan(1,N); ...

6 years ago | 0

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Answered
Create Matrix By Several Matrices These Matrices Have Elements By Equations
Having lots of numbered variables is not a good approach, you should place all of those sub-matrices into one cell array when th...

6 years ago | 0

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Too many input arguments. (the equations and conditions are given i am running the code but giving error kindly suggest me )
The anonymous function F only has one input argument: F = @(as)... but you are calling it with two inputs: f = F(asc,L); Pro...

6 years ago | 0

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How to perform mathematical operation in columns on certain elements and make the other elements zero??
Something fancy... >> M = [0,0;0,0;1,0;2,7;5,8;3,11;4,12;2,9] M = 0 0 0 0 1 0 2 7 5 8 ...

6 years ago | 0

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removing specific values in a cell array
>> A = {1:10,1:10}; % square brackets are not required. >> F = @(a)a(a>=3&a<=8); >> B = cellfun(F,A,'uni',0); >> B{:} ans = ...

6 years ago | 1

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Answered
convert a cell array to 3-d array
B = permute(cat(3,A{:}),[3,1,2])

6 years ago | 1

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Answered
How do I split cells in an array and save data into a bigger cell array?
Use a comma-separated list to help concatenate them into one cell array or string array: >> arr = {'hello i welcome you';'what ...

6 years ago | 0

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Answered
cover cell array into vector
Numeric arrays do not have empty elements: every element has one value. But you can easily store the sizes and recreate the cel...

6 years ago | 0

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Answered
Removing loaded variables from workspace after changing name with eval
Do NOT use eval for such trivial tasks as importing data. Either access the fieldname, e.g. S = dir('C:\MyFolderPath'); N = n...

6 years ago | 0

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Answered
Replacing values in cell array in for loop
It is simpler and more efficient to use max: F = @(m) max(m,spect_threshold); Y = cellfun(F, Y, 'UniformOutput', false);

6 years ago | 0

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Answered
What is the best way to implement thousands of data in multiple matrices ?
I would not use either of the first two methods, because they are an easy way to get latent, almost undetectable errors in your ...

6 years ago | 0

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Answered
Replacing Values Between a 0 and a 1 in a Vector
This should be reasonably efficient: A = [0,0,0,2,2,2,1,2,1,2,2,0,0]; D = diff(A); B = find([0,D]==2); E = find([D==-1,true]...

6 years ago | 0

Answered
Toeplitz Matrix Generation from 2 MATRICES
>> A = rand(3,3); >> B = rand(3,5); >> N = 4; >> F = @(n)(A^n)*B; >> C = arrayfun(F,0:N,'uni',0); >> C = [{zeros(size(B))},...

6 years ago | 0

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Reading data from ASCII file
Importing the entire file data as character, converting to string, spltting that string into multiple little strings, and then f...

6 years ago | 0

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if all elemets of a array equal, which array will be choose by MAX function?
There is no inbuilt function, but you can do it yourself very easily: >> a = [0,0,0,0,0]; >> ida = find(a==max(a)); >> idx = ...

6 years ago | 0

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Answered
How to set the no if iterations of a for loop dynamically ?
The MATLAB approach is to do these two steps before the loop: create a cell array of the folder names use setdiff or ismember ...

6 years ago | 0

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Answered
How to save fields of a struct through for loop iteration.
You don't need a loop, just use the -struct flag to save the fields of a scalar structure: save(filename,'-struct','data') Whe...

6 years ago | 0

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Answered
Declaring types in MATLAB
"When preallocating, is it possible to declare types? " When preallocating you can select any suitable data type, e.g.: A = ze...

6 years ago | 0

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Answered
Multiple outputs by a loop
Replace the fopen with these two lines: fnm = sprintf('output%d.txt',i); fid = fopen(fnm,'wt');

6 years ago | 0

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how can i plot the function of each function?
"what's wrong on this code?" if does not change subsets of an array like that (you would need to use if inside of a loop). You...

6 years ago | 0

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Answered
Skill with regexprep?
This should get you started: >> str = '5*0.02 0.02 0.04 0.08 0.15 0.3 0.5 1 2 3 30*5 30*10 30*20 30*40 30*60'; >> fun = @(n,c)...

6 years ago | 0

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Creating a structure from a cell array with nested structure fields
Nope, that won't work. Best approach: split on the period characters, then use setfield and getfield as appropriate: S.field1....

6 years ago | 0

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Answered
(1/3)*3-1 evaluates to 0 instead of some numerical error. Why?
The reason is very simple: because 1 is the closest (double) binary floating point number that can approximate the value of (1/3...

6 years ago | 2

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Answered
PLEASE HELP ME -- unexpected expression
fprintf('1. kök: %g \n 2. kök: %g \n ',y1,y2); % ^ your code is missing this comma % ...

6 years ago | 0

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Answered
Change of color of variables
The teal color indicates a shared scope for that variable: https://www.mathworks.com/help/matlab/matlab_prog/check-variable-sco...

6 years ago | 0

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Answered
List all cells that match logical criteria
>> C = {1,'13_dogs';[],'24_dogs';1,'100_dogs';[],'7_dogs'}; >> X = cellfun(@(a)isequal(a,1),C(:,1)); >> D = C(X,2); Checking:...

6 years ago | 0

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Answered
Randperm without number 1
r = 1+randperm(N-1,N20);

6 years ago | 0

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Answered
How can I save the outputted string (retaining tabs/added lines) to a .txt file?
[fid,msg] = fopen('yourfile.txt','wt'); assert(fid>=3,msg) fprintf(fid,'%s',MESSAGE); fclose(fid);

6 years ago | 0

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