Jos (10584)

Last seen: 12ヶ月前 | 2006 年からアクティブ

I have been using Matlab since version 4 (1999 or so) and still prefer it over all other software tools available for data manipulation :-)

My professional interests: neuroscience (motor control & eye movements), cognitive psychology physics, mathematics, teaching

"The most important part of programming is writing the comments!"

Statistics

All

バッジを表示

Content Feed

回答済み
for loop taking too long to operate
Pre-allocation, and recoding using logical indexing and sum should speed things up popn1 = nan(300,1) ; % pre-allocation for i...

2年以上前 | 1

| 採用済み

回答済み
How to make columns the same size
A solution: A = [1 3 ; 2 4 ; 5 7] B = [10 11 12 ; 13 14 15] newB = repmat(mean(A,2), 1, size(B,2)) newB(1:size(B,1),:) = B

3年弱前 | 0

| 採用済み

送信済み

COLSHIFT
Circularly shift each column of a matrix

約3年前 | ダウンロード 1 件 |

回答済み
How can I search a cell array for all instances of a character and replace it with something else?
Something along these lines, perhaps? C = {1.1 pi '*' ; 3 '*' 2.2} tf = cellfun(@(x) isequal(x,'*'), C) idx = find(tf)

3年以上前 | 0

回答済み
If a number in a matrix is <9 add 5 to it
Use the same selection on the right hand side of the equal sign A(A<9) = A(A<9) + 5 I myself prefer to code it like this tf =...

3年以上前 | 0

| 採用済み

回答済み
How to set the diagonal of a cell array of matrices?
Well found, Mohammed! You should put as an answer here :-) Here is another method A = cell(4,4) % a cell array n = size(A,1)...

3年以上前 | 0

| 採用済み

回答済み
how to add a row and column to a matrix ?
One easy option is to do this for rows and columns separately A = [1 2 3 ; 4 5 6 ; 7 8 9] x = 3 ; % add a row/column of ones b...

3年以上前 | 5

| 採用済み

回答済み
How can I assign a variable to all the columns and all the rows of a matrix?
Are you looking for the function SIZE? data = rand(20,10) ; [numsubs, numtrials] = size(data)

3年以上前 | 0

| 採用済み

回答済み
Can this line in a code be written in a smarter way?
as others have mentioned before this makes ones head spin ... However, C(:,:,c)=(dC*C(:,:,c)+(dC*C(:,:,c)')'+C(:,:,c)*(-b)+C(:...

3年以上前 | 0

回答済み
Indexing sections of arrays
x = 101:110 n = 3 tf = mod(0:numel(x)-1, 2*n) < n a = zeros(size(x)) a(tf) = x(tf) index = find(tf)

3年以上前 | 1

| 採用済み

回答済み
combinations with 2 columns
Take a look at ALLCOMB on the File Exchange: https://uk.mathworks.com/matlabcentral/fileexchange/10064-allcomb-varargin X = [1...

3年以上前 | 0

回答済み
Combination of 4 Element
I make use of my function NCHOOSE, available here: https://www.mathworks.com/matlabcentral/fileexchange/20011-nchoose % bl is ...

3年以上前 | 0

| 採用済み

回答済み
How to find angle between two lines?
Use the dot product between the two vectors (v1 and v2) given by the four x,y pairs points. Given the formula: dot(v1,v2) = | ...

3年以上前 | 0

回答済み
The most efficient way to locate the first 1's in each row of a matrix
m = [0 1 1 1 ;1 0 1 0; 0 0 1 1 ; 0 0 0 1] % a simple solution [r, c] = find(m') ; clear v1 v1(r,1) = c % another solution ...

3年以上前 | 0

回答済み
Could anyone suggest me is there any way of choosing maximum and minimum values together
Here is a nice trick that also allows you to combine functions in a single call, which also can return the other outputs of thes...

3年以上前 | 1

回答済み
How to have a multiple choice questionnaire that will ask the next question depending on the answer?
Take a look at all the dialog functions in matlab like questdlg, listdlg etc. Start however drawing a graph of all the question...

3年以上前 | 0

回答済み
how to find nearest date corresponding value ?
Does this return what you want? R = AOD_440(closestIndex, [1 2]) % select first (date?) and second (values?) columns

3年以上前 | 0

| 採用済み

回答済み
Plotting an Archimedean Spiral
In the computation of x and y you wrongly multiply b with Th. You should multipy by Th / (2*pi): r = 12.5; %outer radius a =...

3年以上前 | 1

| 採用済み

回答済み
replace duplicate value by 0 in matrix or vector
% for small vectors: b = [1 2 1 3 2 1 4 2] b(sum(triu(b == b')) > 1) = 0

3年以上前 | 1

回答済み
concatenate arrays after performing addition
A little simpler than all those permutes and reshapes: A = [1 2 3 ; 4 5 6 ; 7 8 9] ; B = [2 3 4 5] ; C = repmat(A, numel(B), ...

3年以上前 | 0

回答済み
Alternation without for loop
% a sorting trick A = [1 2 3 4 5 6 7 8 9 10] B = [0.5 0.2 0.4 0.8 0.9] C = [A B] ; [~,ix] = sort([1:numel(A) 1:numel(B)]) C...

3年以上前 | 0

回答済み
Matching closest values to each other
For larger vectors, where BSXFUN will require a lot of memory, function NEARESTPOINT might be useful A = rand(1000000,1) ; B = ...

3年以上前 | 1

| 採用済み

回答済み
Sort Descend Scientific Notation Error
You misuse the sort command. Simply: sortedu = sort(u ,'descend') would do :-) Moreover, if you remove the semicolons, you ...

3年以上前 | 0

回答済み
making an array to simulate states of a paramagnet with values of -1,+1.
Create a random vector with two values and map those to -1 and 1. An easy solution (with n=10): x = 2 * randi([0 1], 1, 10) - 1...

3年以上前 | 0

| 採用済み

回答済み
for loop that changes specific letters to numbers
Another option: str = 'apple'; TF1 = any(lower(str) ~= 'aeiou'.')

3年以上前 | 2

回答済み
Finding Min Value in array with changing condition
tf = a == 1 % create a logical array temp = cost(tf) % logical indexing to retrieve certain values mincost = min(t...

3年以上前 | 0

回答済み
How to genetate random number under constraint
Brute force attempt: N = 20 ; xyRange = [100 1900] ; minimumDistance = 200 ; attempt_counter = 1 ; Distances = 0 ; while ...

3年以上前 | 0

回答済み
Add an element to a 3D array
To concatenate two arrays A and B in the third dimension, use cat cat(3, A, B) Note that all the other dimensions of A and B s...

3年以上前 | 0

回答済み
To concatenate rows in matrix within for loop based on if else statement
This code is weird. In each iteration of "index" you fill either a matrix temp or a matrix temp_noise with m rows of values. T...

3年以上前 | 1

回答済み
To generate matrix from an array
More general, using indexing: A = [1 22 3 44 55 666 7 888 9] n = 2 B = A(((1:numel(A)-n).' + (0:n)))

3年以上前 | 0

さらに読み込む

Jos (10584)

Statistics

Community

MATLAB Answers

MATLAB Answers

Cody

Cody

File Exchange

File Exchange

File Exchange

File Exchange

File Exchange

MATLAB Answers

MATLAB Answers

Content Feed