Community Profile # Chunru

Last seen: Today Active since 2013

Matlab user since 1990

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How to plot the convolution integral of two functions
Use symbolic math: syms x y h tau %x = 0:0.5:10; y = exp(-x); % use -1 and -2 to ensure convolution exist h = exp(-2...

14 hours ago | 0

Error: Edge vector must be monotonically non-decreasin with isosurface
Nx = 32; Ny = 32; Nz = 32; Lx = 2*pi; Ly = 2*pi; Lz = 2*pi; x = (0:Nx-1)/Nx*2*pi; % x coordinate in Four...

14 hours ago | 0

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How to plot envelope of a signal
load t.mat load signal.mat whos plot(t, signal); hold on [yupper,ylower] = envelope(signal,1000, 'peak'); plot(t, yupper, ...

15 hours ago | 0

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Cross Correlation lag issue
P2 = randn(10, 1); P3 = [zeros(5, 1); P2]; % P3 is P2 delayed by 5 [xc2,lags2] = xcorr(P2,P3); plot(lags2, xc2) [rho2,imax...

1 day ago | 0

Adding XYZ axis in RGB colors in the corner of a plot
plot(rand(10,1)) annotation('arrow', [0.8, 0.7], [0.8, 0.75], 'Color', 'r') annotation('textbox', [0.68, 0.70 0.05 0.05], 'Str...

1 day ago | 0

How to label a structure name in a loop
low.t1 = 2; low.t2 = 3; for i=1:2 data = low.("t"+i) end

1 day ago | 0

Reorder vector without for loop
A = randn(583200, 10); B =reshape(A, 540, [], 10); B = permute(B, [2 1 3]); B = reshape(B, 583200, 10); whos % To verif...

1 day ago | 0

using subplot in bar , how to adjust bar width
x1 = [1 2 3]; y1 = [1 2 3 ]; x2 = [1 2 3 4 5]; y2 = [1 2 3 4 5]; % Make xlim same so that the bar width is the same h1= s...

2 days ago | 0

Rotate Basis Vectors Programmatically
V1 = orth(randn(6)) % your original orthonormal basis % Then you can apply any other orthonormal basis to it % For e...

4 days ago | 1

Sorting Values my Integer and Decimal Values
p = [8.1 8.2]; if floor(p(1)) == floor(p(2)) disp("A pair.") end f = [2.1 , 3.1 , 4.1, 5.1, 6.1]; if all(abs(diff(mo...

5 days ago | 1

Correlate Signals with different time points
You can resample the data into sime sampling time: doc resample doc retime doc interp1 After both signals are sampled in the...

5 days ago | 0

How to remove the AWGN noise from data?
Uo=[20 30 40 50]; % signal U=awgn(Uo,30) % add noise to signal % Uo=U-awgn(30); % if you don't know t...

5 days ago | 0

How to trasform from cell to matrix and transpose from horizontal to vertical at the same time?
Data.my_cell{1} = randn(1, 11); Data.my_cell{2} = randn(1, 11); Data.my_cell{3} = randn(1, 11); Data.my_cell my_matrix = cel...

6 days ago | 1

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How do I zoom in on a certain section of a magnitude bode plot
num = ; den = [1 0.04946 3.00316 0.0989847 3.00322 0.0494631 1.00006]; g=tf(num, den) bode(g) grid on ax = findobj(gcf, ...

6 days ago | 0

Obtaining Sine Wave From Square Wave
% generate a square wave with no fixed period f = 0.125; fs=1; s = 0.3+sin(2*pi*f*(0:40)); % a sine wave with offset x =2* (...

6 days ago | 0

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why do I get this error while using qammod? "Expected input number 1, X, to be an array with all of the values < 4."
A few bugs in program. The major one is generating input signa which should bel: tx_bits=randi([0 M-1], [N_data_symbol,1]); N...

6 days ago | 1

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Using trapz function to provide answers using loop
% The way to use trapz x= 1:20; % x y = randn(20, 1); % y ytrapz = trapz(x, y) % integr...

6 days ago | 0

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Storing sparse matrices in cell or struct without converting them to full
The sparse array in cell is still sparse array as shown below, Can you show the problem you have encountered? a = sparse(eye(1...

6 days ago | 0

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How to import exponent number from Excel column to MATLAB
x = readtable("2powx.xlsx") y = cellfun(@(a) sscanf(a, "%d^%d")', x.LSB, "UniformOutput", false) y = cell2mat(y) y = y(:, 1)....

7 days ago | 0

How to fit a gaussian distribution curve on a bar diagram?
p = [1/36,2/36,3/36,4/36,5/36,6/36,5/36,4/36,3/36,2/36,1/36]; xsum =[2,3,4,5,6,7,8,9,10,11,12] ; bar(xsum, p) mu = sum(p.*xsu...

7 days ago | 0

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Why do I get error when using a simple global variable?
Not sure what the code is trying to do. However, the error is due to the wrong usage of ( ) rather than global variables. glob...

7 days ago | 1

How can I plot direction of principal components in PCA
x = randn(4, 2); plot(x(:,1), x(:,2), 'ro', 'DisplayName', 'data'); axis equal; hold on p = pca(x); xc = mean(x); quiver(x...

7 days ago | 0

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Smoothing data with sgolay filter
framelen = 11; order = 3; % adjust these values smootheddata = sgolayfilt(z, order, framelen);

7 days ago | 0

Unrecognized function or variable 'sum'.
classdef question2 methods function q2a = l1qa(~,table) % clear sum; s...

7 days ago | 0

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I have a 2x2 matrix with values [0.5694 -0.8220; -0.8220 -0.5694] How do I plot this matrix?
x = [0.5694 -0.8220; -0.8220 -0.5694] heatmap(x); figure plot(x(:, 1), x(:,2)) % take 1st column as x and 2nd column as y (...

7 days ago | 0

Get the displacement component which is perpendicular to the triangle (finite element)
% In order to know the normal of triangle, you need the coordinated of % triangle postri = randn(3, 3) % x y z v = dif...

7 days ago | 1

Separating a timestamp into individual components
times = [ 20082009 21082009 22082009 23082009]; d = floor(times/1e6); m = mod(floor(times/...

7 days ago | 0

Suppress Window using System Command
cd("C:\Program Files\Bentley\Offshore\MAXSURF CONNECT Edition V23") cmd = "MaxsurfModeler64.exe display off" system(cmd)

7 days ago | 0

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