Akira Agata

MathWorks

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ベクトルと平面のなす角の算出
順を追って説明します。まず、ベクトル a と b のなす角は以下の式で求められます。では平面とベクトル a のなす角は？？というご質問ですが、考えてみると平面の法線ベクトルを使って求められそうです。たとえば平面の法線ベクトルを n とすると...

2 months ago | 2

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Storing values in a matrix out of nested for loops
how about the following? m1 = [0.5; 0.5]; m2 = [0.6; 0.4]; m3 = [0.2; 0.8]; [q, p, r] = meshgrid(m2, m1, m3); s4 = p.*q.*r;...

2 months ago | 0

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Answered
データ数の圧縮,リサンプリング,補間について
時系列信号のリサンプリングに関するご質問と想定して回答します。ご理解のとおり、resample 関数を使ってこの課題を解決するには、目標のサンプル点数に対応するサンプリング周波数を求める必要があります。もっと簡単な別の方法として、関数 interp...

2 months ago | 0

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Answered
Read csv file 2 and 3rd row and store them in different matrices
How about the following? % File path url = 'https://jp.mathworks.com/matlabcentral/answers/uploaded_files/978985/2022-04-22%2...

2 months ago | 0

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Answered
How to convolve a 3D matrix along one of its dimension?
The function smoothdata must be applicable, like: % Sample data A = rand(100, 100, 2000); % Gaussian filter window win = 1...

2 months ago | 1

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This file format i want to extract time and Value. What should I do??
How about the following? % Read and arange the data url = 'https://jp.mathworks.com/matlabcentral/answers/uploaded_files/97604...

2 months ago | 0

Answered
フォルダー内の画像のlab値を読み取り，それぞれの値を変数l,a,bに代入する．
以下のような処理のイメージでしょうか？ % フォルダー内の画像を読み取る． I = imread('peppers.png'); % 画像のlab値を読み取る． Ilab = rgb2lab(I); % 変数l,a,bを定義し，画像のla...

2 months ago | 0

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Answered
行列の各行に対してラベル付け
グラフ理論を使う方法はどうでしょうか？配列Aの各要素をノード番号、各行をエッジとみなすと、配列からグラフGを構成することができます。すると、「求めたいラベル番号」は「エッジが属するサブグラフの番号」と等価になります。言葉だけでは分かりにくいと思...

2 months ago | 2

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Answered
BPSK modulatorブロックの搬送周波数について
おそらく BPSK Modulator Baseband ブロックに関するご質問かと思いますが、このブロックは名称のとおりベースバンド信号を生成します。このため、ある搬送波周波数 [Hz] のBPSK信号を生成するには、このブロックの出力を別途でアッ...

2 months ago | 0

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Answered
Vector to Indicate if Data equals the Maximum by group
How about the following? data = [1;2;3;6;5]; group = [1;1;2;3;3]; idx = splitapply(@(x) {x == max(x)},data,group); idx = c...

2 months ago | 0

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Answered
２つ以上の同じ要素を持つ列を削除
arrayfun 使った別の方法： % 配列の一例 (行・列数は任意) A = [... 1 2 3 4 5;... 2 3 4 4 6;... % -> 削除 7 5 5 5 2;... % -> 削除 0 9 7 8 1];...

3 months ago | 1

Answered
Finding the value of the below curve
If you have a Signal Processing Toolbox, pulsewidth function will be a simple and effective solution.

3 months ago | 0

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finding the slope of each segement in a fitted curve
By applying interpolation, you can decrease and, as a result, the deviation will be more accurate. The following is an example...

3 months ago | 1

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Plot summation series | For Loop | Creep Strain
How about the following? s = 100; % constant tensile stress, (MPa) t = linspace(0, 10000)'; % duration of applied stress on sp...

3 months ago | 0

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構造体から特定のデータを抜き出す方法
関数 structfun をうまく使うと、ID = true の要素だけを抽出した構造体 t01_ver1 を作成することができます（下記 Solution 1）。ただ、このようなデータであればテーブル型変数にしたほうが扱いやすいと思いますので、テーブ...

3 months ago | 0

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Finding the number of edges per each node in a graph
Please reffer to the degree function.

3 months ago | 0

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Convert a table vector of 31 by 13 elements to matrix of 13 by 31.
How about the following solution? % Read data file L = readlines('https://jp.mathworks.com/matlabcentral/answers/uploaded_file...

3 months ago | 0

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Answered
Inserting a column of repeated values
How about the following method? % Sample data load('outdoors.mat'); T = timetable2table(outdoors); T.Humidity([1, 6, 15]) = ...

3 months ago | 0

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Answered
Combination of DATA in arrange manner
How about the following? % Create D and E D = -0.02+0.0001*(0:70); E = 160:200; % Apply meshgrid function [xg, yg] = mesh...

3 months ago | 1

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Answered
Find out the cell index from matric values
How about using histcount2 ? The following is an example: % Sample data A = [... 0.7, 0.1;... 0.1, 0.2;... 0.8, 0.6;...

3 months ago | 0

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Answered
Best way to get rid of/ prevent function from creating complex numbers?
How about using isreal function?

4 months ago | 0

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Create all permutations of 1x13 vector used for Leave-p-out Cross-Validation
How about the following? Though this generates 78x11 (instead of 13x78 which you expected), the result contains all possible co...

4 months ago | 0

Answered
return value of [ ] for an 'if' or 'for' function
How about the following? function output = yourFunction(input) if isempty(input) output = 'unknown'; elseif isa(input,'n...

4 months ago | 0

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Answered
How to speed up my code?
Avoiding for-loop will enhance computational efficiency. For example, the first for-loop: for i=1:n2 K(:,:,i)=M(:,:,i); en...

4 months ago | 0

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Answered
How to use 'mkdir' command to make folders labelled as 1, 2, 3 till 100 using for loop in matlab code?
How about the following? rootFolder = 'E:\P2'; for kk = 1:100 subFolder = num2str(kk); folderPath = fullfile(rootFolde...

5 months ago | 0

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Answered
How to calculate the number from a database
How about the following? List = arrayfun(@(x) x.country, TV,... 'UniformOutput', false); [Group, Country] = findgroups(Li...

7 months ago | 1

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Answered
行列からある条件を満たした部分以降を抽出する方法
find 関数を使う下記の方法ではいかがでしょうか？ % A の2列目が >= 1 となる最初の行番号を pt として取得 pt = find(A(:,2) >= 1, 1); % pt行目から最後までの行を配列 B として保存 B = A(p...

7 months ago | 1

Answered
Assign number to certain value in cell
How about using ismember function? Like: % Sample cell arrays A = {'As', 'C', 'H', 'N'}; B = {'As', 'As', 'N', 'N', 'H', 'H',...

7 months ago | 0

Answered
replacing numbers with alphabets/letters in a matrix
One possible straight-forward solution would be like this: M = readmatrix('testfile_0.50.xlsx'); C = cell(size(M)); idx = i...

8 months ago | 0

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Answered
Assign partnames to two different tables with measurement datas
I wouold recommend using innerjoin or outerjoin functions for this kind of task.

8 months ago | 0