Community Profile

photo

Peng Li


Last seen: Today
134 total contributions since 2020

Peng Li's Badges

  • Revival Level 2
  • 3 Month Streak
  • Thankful Level 1
  • Knowledgeable Level 3
  • First Answer

View details...

Contributions in
View by

Answered
How can I fit a linear mixed-effects model with only quadratic/second-order terms?
This is an old post now. Just for future readers, you can explicitly get rid of any items you don't want by minus it. For the qu...

3 hours ago | 0

Answered
How to interpret FFT output signal?
Based on your code, your sampling frequency is 1/3 Hz. There is no way you can detect a component of 0.316 Hz using 1/3 Hz sampl...

3 hours ago | 0

Answered
Which formula fits better for this Linear Mixed-Effects Model?
To understand your dataset, I still believe that descriptive statics can give you the broad general picture. In terms of statist...

17 hours ago | 0

Answered
readtable with multiple date formats
A workaround for me I think is to just load that column in string format. After loading you can do some cleaning before you conv...

20 hours ago | 0

Answered
Averaging subsets of a large dataset
You can load this datasheet to matlab using readtable. after that, you have a table variable that allows easier manipulation. T...

1 day ago | 1

| accepted

Answered
Integrate kernel probability distribution function
https://www.mathworks.com/help/matlab/ref/trapz.html trapz is a function that deals with numerical integration. Check the above...

1 day ago | 0

Answered
LME and multiple comparisons
If I understand your question correctly, you were asking a post hoc comparison issue? coefTest method of LinearMixedModel object...

1 day ago | 0

Answered
I am looking for a function in R that can help me deal with the different structures of the variance-covariance matrix. And thank you in advance
are you looking for solutions in MATLAB or in R? This is the community for MATLAB. and get back to your question, fitlme or fit...

1 day ago | 0

| accepted

Question


speed up renamecats/categorical multiple columns
I have a huge csv file of about 16GB which over 9k columns. Each column is initially filled with some codes (either integer or s...

3 months ago | 0 answers | 0

0

answers

Answered
Extracting and plotting max/min values from timeseries
Better take advantage of table format and splitapply function. tbl = readtable('data.csv'); tbl.day = day(tbl.Date); tbl.h...

3 months ago | 0

| accepted

Answered
What does the ' symbol mean?
transpose. https://www.mathworks.com/help/matlab/ref/transpose.html

3 months ago | 0

| accepted

Question


datastore readsize and buffer chunk
I am working with a single csv file of over 10G size. I'm trying to use mapreduce to perform some analyses. The program works as...

3 months ago | 1 answer | 0

1

answer

Answered
How can i get contour plot like this?
https://www.mathworks.com/help/matlab/ref/contourf.html This might be what you need.

3 months ago | 1

| accepted

Answered
Can some one please tell me how to find the maximum amplitude frequency of the ecg signal? I have attached below my code. I keep getting maximum frequency at 0 Hz.
try Y = fft(ecgData - mean(ecgData), NFFT); It is expected that the DC contains most of the energy of the signal. You could e...

3 months ago | 0

| accepted

Answered
Having trouble with legend
Try this %Line Colors strColor = {'-r','-g','-b'}; %Legend String strLegend = {'nSamples = 5','nSamples = 10','nSamples = 15...

3 months ago | 0

Answered
convert a double matrix in cell within a table
t = table([ones(1, 4); ones(1, 4)*2; ones(1, 4)*3]) t = 3×1 table Var1 ________________ 1...

3 months ago | 1

| accepted

Answered
Finding average of a large csv file
why do you need a loop? you said you have ONE cvs file with 1 column and 301 rows? you just need to import the cvs file and do t...

3 months ago | 0

Answered
Indices of the values for which two conditions are true
tbl = table(abbrev(:), firstword(:), number(:)); [gp, outTbl] = findgroups(tbl(:, 1:2)); outTbl.sum = splitapply(@sum, tbl.(3)...

3 months ago | 0

| accepted

Answered
Help with Linear Mixed effects model formulas
For statistical questions, the first thing we ask is what the hypothesis is. From your equation, I guess you'd like to examine ...

3 months ago | 1

Answered
How can i export data from an 'edit text box' in app designer to an excel file?
I assume that you have properties linked to each of these values. In the callback, you can create a structure or a table involv...

3 months ago | 0

Answered
Is There a Way to Execute splitapply Functionality on Subtables of Master Table?
you'd better do this way: splitapply(@(x) sum(x, 1), T{:, 2:3}, G);

3 months ago | 0

Answered
HOW TO FIND THE R-SQUARED VALUE
mdl.Rsquared check https://www.mathworks.com/help/stats/linearmodel.html for properties and methods related to linear regressio...

3 months ago | 0

| accepted

Answered
What is the reference category in the output for a Fitlme with categorical variables and three-way interaction terms?
The table you copied isn't the default display from matlab, so it's difficult to tell anything from there. It's like an ANOVA ou...

3 months ago | 0

| accepted

Question


Reduce function if concatenated intermediate results doesn't fit in memory
I'm trying to decode a huge dataset of rougly 500k*10k size. What I'm doing is actually load the file into a datastore, replace ...

3 months ago | 0 answers | 0

0

answers

Answered
Reading EEG data downloaded from University of Bonn
This is a single channel EEG database. Each zip file has 100 txt files. Each txt file has 4096 samples . What does this mean ? ...

3 months ago | 0

| accepted

Answered
custom labels for errorplot
using annotation annotation('textbox', pos, 'String', str, 'FitBoxToText', 'on'); pos is the position where you want to put th...

3 months ago | 0

| accepted

Answered
How to find the max value of amplitude in Fast Fourier Transform function?
I believe it is correct. you can always test it by plotting them. plot(freq, SSAS); hold on; plot(freq_max, SSAS_max, 'ro'); a...

3 months ago | 0

Answered
MATLAB does not recognize the matrix
qlt_pts = u(kk) * score(kk); your score is a char array. so what do you want this multiplication to give you?

3 months ago | 0

Answered
Converting these 5 lines of MATLAB code to C++?
As creating a vector that increments by 3. So is the first line creating an array of values that starts at one, increments by 2,...

3 months ago | 0

| accepted

Answered
How can I check if a table contains numbers only?
I guess your question re the x-values isn't quite clear. For the first part of your question, it is tricky to determine whether...

3 months ago | 1

| accepted

Load more