https://ww2.mathworks.cn/matlabcentral/answers/questionsMATLAB Answers — New Questions2020-01-20T03:29:58Ztag:ww2.mathworks.cn,2005:Question/5010202020-01-20T01:05:09Z2020-01-20T03:29:58ZHow to split an array into two arrays? Hi,
I have an array like x = [ 0:10] and need to split it into x1 = [x(0,1),x(4,5),x(8,9)] and x2 = [x1(2,3),x(6,7)]. I am able to do this by using loops but for big dara is very time consuming. Is there any other way to do this?
Thanks
Mohammad Torabihttps://ww2.mathworks.cn/matlabcentral/profile/authors/6009385-mohammad-torabitag:ww2.mathworks.cn,2005:Question/5008982020-01-18T18:14:08Z2020-01-20T03:22:35Z3D Plotting in matlabI have got a function after integration in Matlab, f($\theta$,$g$) which is a complex function. I would like to get 3D plot the this function with respect to $\theta$ and g, where $g$ positive integer runs from 0 and $\theta $ runs from 0 to $\pi$. The function is very large and complicated one. Pl hep me to plot this.P Maityhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17312484-p-maitytag:ww2.mathworks.cn,2005:Question/4999482020-01-12T04:34:03Z2020-01-20T03:13:10ZHow to find the valley areas of the image?How to calculate the depth of the letters in the given image, so that i can find the valley areas ? Please help me.Skhttps://ww2.mathworks.cn/matlabcentral/profile/authors/16144792-sktag:ww2.mathworks.cn,2005:Question/5009642020-01-19T13:18:49Z2020-01-20T03:09:21ZClassification learner app input issueThe Classification learner app is only able to add one csv file for each session. May I know how is it able to add several csv file in order to train the classifier ? Otherwise how can I combine few excel file into one to train the classifier ?
Any suggestion or I can do because my train set is around 500 images. Teik Jin Limhttps://ww2.mathworks.cn/matlabcentral/profile/authors/9770976-teik-jin-limtag:ww2.mathworks.cn,2005:Question/5009602020-01-19T13:00:06Z2020-01-20T03:04:39Zhow to plot to get four plots of descriptive statistics in one figureI have attached the descriptive statistics of 4 different zones below.
Can you help me how to get the four plots in one figure?
I would like something like this https://se.mathworks.com/help/stats/exploratory-data-analysis.html
gjashtahttps://ww2.mathworks.cn/matlabcentral/profile/authors/12107468-gjashtatag:ww2.mathworks.cn,2005:Question/5010252020-01-20T02:54:12Z2020-01-20T02:54:12ZHow to convert gray image to HSV plane S - value image?Hi,
Given my image is a gray image and i don't have the rgb image of this gray image, can i know how can i convert this gray image to the HSV colour plane S - value plane image only?elsa changhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17319033-elsa-changtag:ww2.mathworks.cn,2005:Question/5010242020-01-20T02:44:35Z2020-01-20T02:44:35ZHow to convert datenum to datetime in a MATLAB TableHello, I have a table with list Ids in numbers and corresponding datenum in which these Ids were occured. Can you please help me to convert these datenum to dates?
The table is like this:
ID_1 Dates_1 ID_2 Dates_2
2 737735.191331019 6 737735.182129630
3 737735.182013889 7 737735.141481482
I tried this:
for counter= 1:(size(table,1))
if mod(counter,2)==0
col_name=table.Properties.VariableNames{counter};
table{:,col_name}=datetime(table{:,col_name},'ConvertFrom', 'datenum');
end
end
And i got error like this:
The following error occurred converting from datetime to double:
Undefined function 'double' for input arguments of type 'datetime'. To convert from datetimes to numeric, first subtract off a datetime origin, then convert to numeric using the SECONDS, MINUTES, HOURS, DAYS, or YEARS functions.Shambhavi Adhikarihttps://ww2.mathworks.cn/matlabcentral/profile/authors/12839231-shambhavi-adhikaritag:ww2.mathworks.cn,2005:Question/5009262020-01-19T05:00:36Z2020-01-20T02:43:43ZError in resizing GUIDE guiHello,
I am using GUIDE, and now am getting this error in modifying a GUIDE gui. The gui works, but not sure what's going on here!
Thanks..
Doug AndersonDouglas Andersonhttps://ww2.mathworks.cn/matlabcentral/profile/authors/4227986-douglas-andersontag:ww2.mathworks.cn,2005:Question/5006782020-01-17T01:36:45Z2020-01-20T02:43:21ZCan I receive real LTE data with zynq board & RF board?I have zc706 and FMCOMMS5.
I succeded to run example : Transmit and Receive LTE MIMO Using Analog Devices AD9361/AD9364
but, I want to receive the REAL LTE data in the air.
Can I receive real LTE data?
Thanks a lot.sarang Kimhttps://ww2.mathworks.cn/matlabcentral/profile/authors/10394942-sarang-kimtag:ww2.mathworks.cn,2005:Question/5006772020-01-17T01:34:32Z2020-01-20T02:37:49ZHow to make predictions using an already-trained LSTM model? Hello everyone,
I have the attached example LSTM code with the data file (omni.txt: hourly data).
I would like to know how to use the trained LSTM model to make a prediction for new data.
I think the answer lies within the lines starting from line 113, but I'm a novice with LSTM.
----------------------------------------------------------------------------------------------------------------------------------
A side question:
This code is dealing with only one input (feature) to predict its own evolution with time, How can we transform it to deal with several inputs at once?
How can we transform this code to take several inputs and predict the temporal evolution of another output?
For instance, like the feedforward backpropagation network in which it can take several inputs to predict a single output (or several outputs).
I appreciate your help!
Thank you, Mohamed Nedalhttps://ww2.mathworks.cn/matlabcentral/profile/authors/7573601-mohamed-nedaltag:ww2.mathworks.cn,2005:Question/5010032020-01-19T19:53:01Z2020-01-20T02:29:02ZHow to create a best fit line for data with an aymptote?I am currently trying to find the point at which the data reaches its max, the asymptote. However, te data fluctuates, so I need to create a best fit line, since finding the derivative of the data as it is now would not work. How would I programatically go about creating a best fit line for this? I need to be able to acess the equation from the code. The data takes the form of the attached images.Evan Shimounhttps://ww2.mathworks.cn/matlabcentral/profile/authors/16122404-evan-shimountag:ww2.mathworks.cn,2005:Question/5010232020-01-20T02:28:39Z2020-01-20T02:28:39ZHow to smooth out a surf plotI want a nice and smooth surface. Can someone please give me some hints ?
clear
zspan = linspace(0,2,100);
v2in_vals = linspace(0.01,0.05,10);
v0mat = [1 0.1 1];
N = size(v0mat, 1);
zsol = cell(N,1);
v1sol = cell(N,1);
v2sol = cell(N,1);
v3sol = cell(N,1);
v2in = cell(N,1);
for k=1:length(v2in_vals)
v0 = v0mat;
v0(2) = v2in_vals(k);
[z,v] = ode45(@rhs,zspan,v0);
zsol{k} = z;
v1sol{k} = v(:,1);
v2sol{k} = v(:,2);
v3sol{k} = v(:,3);
v2in{k} = v0mat(2) * ones(size(v2sol{k}));
end
all_z = [zsol{:}];
all_v2 = [v2sol{:}];
all_v2in = [v2in{:}];
v2in_vec = v2in_vals;
z_vec = all_v2(:,2);
surf(z_vec, v2in_vec, all_v2.')
xlabel('z');
ylabel('dw');
zlabel('w');
function parameters=rhs(z,v)
alpha=0.116;
db= 2*alpha-(v(1).*v(3))./(2*v(2).^2);
dw= (v(3)./v(2))-(2*alpha*v(2)./v(1));
dgmark= -0.01-(2*alpha*v(3)./v(1));
parameters=[db;dw;dgmark];
endTigist Beyenehttps://ww2.mathworks.cn/matlabcentral/profile/authors/14703804-tigist-beyenetag:ww2.mathworks.cn,2005:Question/5010212020-01-20T01:32:22Z2020-01-20T01:58:31ZOutput argument "XXX" (and maybe others) not assigned during call to "function".Not sure what this means. Code here:
global T d t v
T = 10;
d = 0.3;
[t,v]= ode23(@pwm,[0:1e-7:0.1], [0 0], options);
v = pwm(t,T,d);
figure,plot(t,v); %%Plot the datas
%Below is the function declaration, in a different file in the same folder.
function v = pwm(t,T,d)
if T <= t <d*T
v = 1;
end
if d*T <= t <T
v = 0;
end
endOscar Iphttps://ww2.mathworks.cn/matlabcentral/profile/authors/16442085-oscar-iptag:ww2.mathworks.cn,2005:Question/5007442020-01-17T13:47:05Z2020-01-20T01:44:21ZHow to create a table of 3 variables ?I have a matrix Thm = [hours,days,months], where hours is [1x24], days is [1x31] and months [1x12]. I would like to create a table of hours and days [hours, days] for each month. I was wondering if i could substitute a vector of months 1:12 to a vector of a string {'Jan','Feb',...}...Could anyone help me with this, please ?Aleksandra Ksiezykhttps://ww2.mathworks.cn/matlabcentral/profile/authors/7645635-aleksandra-ksiezyktag:ww2.mathworks.cn,2005:Question/5009862020-01-19T17:21:11Z2020-01-20T01:37:10Zdgemv produces only zero vectors as resultsHello, I am trying to link this simple matlab script
A = [2 3; -1 4];
B = [5; 3];
C = zeros(2, 1);
alpha = 1;
beta = 1;
C = mv_mult(A, B, alpha, beta)
with the following mexFunction
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "blas.h"
#include "mex.h"
#include "matrix.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
/* pointers to input & output matrices*/
double *A, *v, *Y, *a, *b;
ptrdiff_t rows_A, cols_A;
ptrdiff_t rows_v, cols_v;
// create input matrix (A)
A = mxGetDoubles(prhs[0]);
rows_A = mxGetM(prhs[0]);
cols_A = mxGetN(prhs[0]);
// create input vector (v)
v = mxGetDoubles(prhs[1]);
rows_v = mxGetM(prhs[1]);
cols_v = 1;
// parse scalars (a, b)
a = mxGetDoubles(prhs[2]);
b = mxGetDoubles(prhs[3]);
// create output matrix (Y)
plhs[0] = mxCreateDoubleMatrix(rows_A, cols_v, mxREAL);
Y = mxGetPr(plhs[0]);
printf("A[0]: %lf\n", A[0]);
printf("A[1]: %lf\n", A[1]);
// compute mm multiplication using blas2 operations
char chn = 'N';
const long int i_one = 1;
dgemv_(&chn, &rows_A, &cols_A,
a, A, &cols_v,
v, &i_one,
b, Y, &i_one);
}
The function compiles without errors nor warnings but matlab replies with [0 0]' instead of [19 7]'. I can't understand why though. Note that I am trying to use blas2 operations only.Nikolaoshttps://ww2.mathworks.cn/matlabcentral/profile/authors/16951974-nikolaostag:ww2.mathworks.cn,2005:Question/5008942020-01-18T17:25:55Z2020-01-20T01:28:00ZRMSE between original and predicted values.Hi,
If I have thousand samples of my signal in a vector form like 1*1000, and I will predict my signal at each iteration that results into 1*1000 also. Then In this case, how will I find the RMSE of my model?
Many Thanks
Asad Rasheedhttps://ww2.mathworks.cn/matlabcentral/profile/authors/15162628-asad-rasheedtag:ww2.mathworks.cn,2005:Question/5010092020-01-19T22:03:03Z2020-01-20T01:09:34ZBlank figures using plotI am running the following code and when the figures pop-up, they are blank without any lines.
I have tried running the Matlab in the software mode, thinking that the problem is in the OpenGL, but nothing changed.
So the error must be in the code , but I cannot figure out where. I appreacate any help on this, as I am stuck..
c1=3.74*10^8;
c2=1.44*10^4;
T1=30;
T2=90;
T3=120;
a1=0;
a2=0;
a3=0;
max1=0;
max2=0;
max3=0;
figure(1);
for a=0:0.01:300
M=c1/((a^5)*(exp(c2/(a*T1))-1));
plot(a,M,'b')
if M>max3
max3=M; a3=a;
end
hold on
end
figure(2);
for a=0:0.01:80
M=c1/((a^5)*(exp(c2/(a*T2))-1));
plot(a,M,'r')
if M>max2
max2=M; a2=a;
end
hold on
end
figure(3);
for a=0:0.01:80
M=c1/((a^5)*(exp(c2/(a*T3))-1));
plot(a,M,'g')
if M>max1
max1=M; a1=a;
end
hold on
endIvaylo Ivanovhttps://ww2.mathworks.cn/matlabcentral/profile/authors/7687354-ivaylo-ivanovtag:ww2.mathworks.cn,2005:Question/867172013-09-09T15:17:06Z2020-01-20T01:01:43ZHow to convert a video file to a bit stream in matlab?I'm trying to extract the motion vectors from a h.264 coded video. For this, I need to convert the video to its a respective bit stream first. Any idea or lines of code to do this will be appreciated.Joelhttps://ww2.mathworks.cn/matlabcentral/profile/authors/4074689-joeltag:ww2.mathworks.cn,2005:Question/5010192020-01-20T01:00:23Z2020-01-20T01:00:23ZHow to increase font size in the System Identification app window on Mac OS X?I've just started using the System Identification app for a course I am taking. I have an Apple Mac Mini with a 27" Thunderbolt display. When I open the System Identification app it appears very small on the display and the fonts are so small they are straining my eyes.
I know how to increase the font size in the main MATLAB_R2019b application (in MATLAB > Preferences) but it doesn't change the font in the System Identification app. I see Simulink preferences but no font setting there.
Couldn't find anything about fonts in the System Identification App help pages (although there is no search function).
System details
Mac Mini, 2012, OS X Mojave 10.14.6
Apple Thunderbolt Display, 27-inch, (2560×1440 pixels)
MATLAB: R2019b Update 2
System Identification Toolbox 9.11Bill Tubbshttps://ww2.mathworks.cn/matlabcentral/profile/authors/4985015-bill-tubbstag:ww2.mathworks.cn,2005:Question/5010182020-01-20T00:54:48Z2020-01-20T00:57:02ZHow to read an plot with coordinates a .tiff file?I'm currently using this code:
[X,map]= imread('Z1.tiff');
image(X);
colormap(map);
This is the file im trying to read: http://www.mediafire.com/view/dzifgp0s3ima3z2/Z1.tiff/file
And this is the plot im trying to obtain:
Any idea why my code is not working? Philippe Cornerhttps://ww2.mathworks.cn/matlabcentral/profile/authors/7103813-philippe-cornertag:ww2.mathworks.cn,2005:Question/3307942017-03-20T09:24:18Z2020-01-20T00:40:31ZField List of IQFeed Realtime DataHi,
I am getting IQFeed realtime data via MATLAB using a built-in function 'realtime'. As the data format is 1x67 cell for each record, I do not know the meaning of each column in one record. Could you please give me the field list for these 67 columns of data?
I also want to know the data sending frequency. I got one more question is when will you send me a new data (I mean what is the minimum difference between the adjacent data).
Any help is appreciated!Rui Zhanghttps://ww2.mathworks.cn/matlabcentral/profile/authors/8609554-rui-zhangtag:ww2.mathworks.cn,2005:Question/5010172020-01-20T00:34:11Z2020-01-20T00:34:11ZAssigning values to the array of Enumeration Class seems to be very slowHi, I met this problem when parsing a gps log.
I made an Enumeration Class GpsState as follows.
classdef GpsState
enumeration
Lost
Single
RTD
RTK_Float
RTK_Fix
end
end
Then I created an array of GpsState to record all the states of the log. The process was painfully slow.
Finally, I found out what the problem was caused by the assign of Enumeration Class array.
I simplified the code as follows, the process takes about 4.6s.
tic
test_num = 1e5;
gps_state = repmat(GpsState.Lost,test_num,1);
for ii = 1:test_num
gps_state(ii) = GpsState.RTK_Fix;
end
toc
Is there any problem with my usage mode of Enumeration Class?
Thanks for your reading.pingping zhanghttps://ww2.mathworks.cn/matlabcentral/profile/authors/15381093-pingping-zhangtag:ww2.mathworks.cn,2005:Question/4934192019-11-27T05:22:53Z2020-01-20T00:28:00ZDefining Simulink block parameters which are dependent on a signal value in Simulink I would like to define one of the parameters of a block in simulink as a function of the value of a signal in simulink. For example, suppose that I want to define the amplitude of a Sine wave as the RMS value of a random signal. How can I do that? Ali Hajnayebhttps://ww2.mathworks.cn/matlabcentral/profile/authors/13465240-ali-hajnayebtag:ww2.mathworks.cn,2005:Question/4592842019-04-30T01:11:35Z2020-01-20T00:26:56ZDatafeed Toolbox IQFeed Level 1 Data Fields DescriptionWhere can I get a list of the fields returned by the realtime command from the Datafeed Toolbox? For example:
realtime(q,'ABC')
openvar('IQFeedLevelOneData')
returns the 67 fields from IQFeed. Where can I get a description of the fields?Marc McLeanhttps://ww2.mathworks.cn/matlabcentral/profile/authors/14895585-marc-mcleantag:ww2.mathworks.cn,2005:Question/2928192016-06-29T03:16:55Z2020-01-20T00:26:39ZCalculating a time duration from the graphHello
I am interested in finding out the time between two points in a graph (x-axis is the time, y-axis is the quantity of interest). For testing my logic, I'm using a sinusoidal wave to see if I get the correct responses. In the sinusoidal wave defined below, I'm interested in calculating the starting and ending x-coordinate when the y-axis value is less than 0.4.
t= [0:0.1:2*pi];
a=sin(t);
figure;
h=plot(t,a);
for i=1:max(t)
y=get(h,'ydata');
if a < 0.4
start=get(h,'xdata');
if a > 0.4
fin=get(h,'xdata');
end
end
This is an infinite loop, which doesn't give any output. I'm not really familiar with matlab and am not able to figure out how to get the start and fin values above.
Any help is appreciated.
Thanks!Mridul Garghttps://ww2.mathworks.cn/matlabcentral/profile/authors/7142910-mridul-gargtag:ww2.mathworks.cn,2005:Question/5008592020-01-18T11:58:21Z2020-01-20T00:10:21ZHelp text does not work for user-defined functionsI just installed R2019b and the help function does not work. Example: I created the addme function from the Add Help for Your Program page in the documentation. Result:
>> help addme
addme is a function.
c = addme(a, b)
The help text in the file was not shown. Also:
>> help help
help not found.
A similar question was asked before, but the answer was not very helpful for me.
help seems to work ok for built-in functions.Are Mjaavattenhttps://ww2.mathworks.cn/matlabcentral/profile/authors/3934907-are-mjaavattentag:ww2.mathworks.cn,2005:Question/5006992020-01-17T06:57:56Z2020-01-20T00:07:55Zeigs gives wrong eigenvaluesHi,
I am using MATLAB R2019b to compute eigenvalues of sparse matrices and discovered that eigs gives wrong results if I only ask for the first several smallest eigenvlues.
The sparse matrices come from the mass and stiff matrices of an ANSYS model I build for modal analysis. Here I provide the toy example of a mass connected to the ground with a translational spring, and I know for sure that this toy example will have eigenvalues with real parts and NO imaginary parts.
Here is my question:
If I compute all the 1047 eigenvalues in my toy example by eig and eigs, I can get matching and correct results. However, if I use eigs to compute only the first several smallest eigenvalues, it gives wrong results with imaginary parts! To be specific, if I ask eigs to give out eigenvalues for the first 523 smallest eigenvalues (the length being equal or shorter than half of 1047), the results are WRONG. eigs only computes correctly when I ask for more than half of the available eigenvalues. I have read many posts on this forum about why eigs is different than eig, due to the former uses the random start, but this does not solve my problem.
My real ANSYS model is way more complex than this toy example, and I cannot afford to use eig to find all eigenvalues, instead, I will use eigs to find the first 20~50 smallest eigenvalues. What can I do with eigs being wrong when I ask it to give eigenvalues shorter than half of the total available eigenvalues?
I have included my data and script blow.
Thank you,
Chiao-Ting
clear; close all; clc;
K = load('stiff_mtx_NoMass.txt'); % Symmetric sparse matrix in MMF format
K = spconvert(K(2:end,:));
K = K + K' - speye(size(K,1)).*diag(diag(K));
M = load('mass_mtx_NoMass.txt');
M = spconvert(M(2:end,:));
M = M + M' - speye(size(M,1)).*diag(diag(M));
[V, D, flag] = eigs(K, M, 523, 'sm'); % NG
% [V, D, flag] = eigs(K, M, 524, 'sm'); % OK
% [V, D, flag] = eigs(K, M, 1047, 'sm'); % OK
D = diag(D);
vecWn = sqrt(D)/2/pi;
K2 = full(K);
M2 = full(M);
[V2, D2] = eig(K2, M2);
D2 = diag(D2);
D2 = sort(D2);
vecWn2 = sqrt(D2)/2/pi;
figure(1); clf;
plot(real(vecWn2), 's-', 'markersize', 4); hold on;
% plot(imag(vecWn2), '+-', 'markersize', 4);
plot(real(vecWn), 'x-', 'markersize', 4);
% plot(imag(vecWn), 'o-', 'markersize', 4);
grid on;
xlabel('DOF');
ylabel('Eigenfrequency (Hz)');
legend('eig; Re(\omega)', 'eigs; Re(\omega)');
set(legend, 'location', 'northwest');
Chiao-Ting Lihttps://ww2.mathworks.cn/matlabcentral/profile/authors/10052213-chiao-ting-litag:ww2.mathworks.cn,2005:Question/991272009-06-27T01:11:00Z2020-01-20T00:04:33ZWhy does the HOLD ON command not work when I try to update figures with subplots?I have subplots in my figure. I execute HOLD ON before making changes to the subplots, however the plot on one of the axes gets removed when I make changes. As an example consider the following code:
figure(1),
h1 = subplot(1,2,1),line
h2 = subplot(1,2,2),line
hold on
figure(1)
axes(h1),plot(sin(0:1))
axes(h2),plot(sin(0:1))
% subplot(1,2,1),plot(sin(0:1))
% subplot(1,2,2),plot(sin(0:1))MathWorks Support Teamhttps://ww2.mathworks.cn/matlabcentral/profile/authors/4622813-mathworks-support-teamtag:ww2.mathworks.cn,2005:Question/5008452020-01-18T08:31:00Z2020-01-19T23:57:00ZWhere's the debug tab?On the page Start the Simulink Debugger the text mentions a Debug tab. Where can I find it?Starhowlhttps://ww2.mathworks.cn/matlabcentral/profile/authors/6025396-starhowltag:ww2.mathworks.cn,2005:Question/5009902020-01-19T18:03:02Z2020-01-19T23:52:32Zhow can i solve this error?dx=0.1;
x=1:dx:6;
b=0.32;
ki=0;
for i=2:length(x)
temp(i-1,:)=Es*I*...
(- b^2*cos(x(i-1,:)*b) - b^2*cosh(x(i-1,:)*b) - ((cos(6*b) + cosh(6*b))*(b^2*sin(x(i-1,:)*b) + b^2*sinh(x(i-1,:)*b)))/(sin(6*b) + sinh(6*b)));
ki(i-1,:)=temp(i-1,:)*dx;
end
Es and I are constant.
error is
Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is
1-by-51.
Error in m2 (line 69)
ki(i-1,:)=temp(i-1,:)*dx;zahra zamanihttps://ww2.mathworks.cn/matlabcentral/profile/authors/16077155-zahra-zamanitag:ww2.mathworks.cn,2005:Question/5010152020-01-19T23:24:33Z2020-01-19T23:50:54ZProblem finding the nearest value to specific numberHello,
I am using this code seen in this thread:
https://es.mathworks.com/matlabcentral/answers/375710-find-nearest-value-to-specific-number
%Initial amplitud (50%time - 10%time)
time_10=((max(A)-min(A))*0.1)+min(A);
time_50=((max(A)-min(A))*0.5)+min(A);
[~,~,idx]=unique(abs(A-time_10));
[~,~,idx2]=unique(abs(A-time_50));
minVal_10=A(idx==1);
minVal_50=A(idx2==1);
T10=find(A==minVal_10); %Gives you the row where 10% of the time lies in the Intensity matrix
T50=find(A==minVal_50); %Gives you the row where 50% of the time lies in the Intensity matrix
I_T10=B1(T10,1);
I_T50=B1(T50,1);
ini_Amp=(I_T50-I_T10)*10^6;
However, I have problems with minVal_50. there are two values equally near to time_50. Therefore I got this warning:
Matrix dimensions must agree.
Error in foot_signal_analysis1 (line 60)
T50=find(A==minVal_50); %Gives you the row where 50% of the time lies in the Intensity matrix
T50=10.53350, and minVal_50 is either 10.53352 or 10.53348. How can I code to take the biggest number in this case? If statement?Jose Rego Terolhttps://ww2.mathworks.cn/matlabcentral/profile/authors/10100100-jose-rego-teroltag:ww2.mathworks.cn,2005:Question/3128902016-11-18T13:13:07Z2020-01-19T23:50:12ZWith eSignal/InteractiveData being discontinued in the DataFeed Toolbox, are there any other "mid-range" cost options for financial vendors?eSignal/InteractiveData is being discontinued in the DataFeed Toolbox. Any other "mid-range" cost options, that aren't $30,000+ per year for a data terminal, other than IQfeed which is mainly N. American data? Free data sources work for testing, but actual trading needs something more reliable. I think my only cost effective workaround is importing real-time interday data into excel and then reading that into Matlab at one minute intervals. Any suggestions?Richard McKeehttps://ww2.mathworks.cn/matlabcentral/profile/authors/488937-richard-mckeetag:ww2.mathworks.cn,2005:Question/5010122020-01-19T23:03:22Z2020-01-19T23:48:16ZCan I have an older runtime environment than the complier version I am using?For several reasons, I am using R2018a for distributing my software. I have discovered that on the Mac that the installers that the Matlab compiler generates do not run under Catalina (they just sit there displaying their splash screen). This situation has lead me to wonder if I can compile under the latest version of Matlab but have the compiler use R2018a's runtime library. Even if this does does not my installer problem, it would be very useful to have this ability.Donhttps://ww2.mathworks.cn/matlabcentral/profile/authors/49289-dontag:ww2.mathworks.cn,2005:Question/5010162020-01-19T23:27:21Z2020-01-19T23:46:30ZThis link pops up when I'm trying to download MATLAB through my school https://www.mathworks.com/licensecenter/total_headcount/6678493399004520332698519 why is it saying this?Michael Dotsonhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17318280-michael-dotsontag:ww2.mathworks.cn,2005:Question/5009992020-01-19T19:32:11Z2020-01-19T23:46:02ZDon't know how to make the loop works with variable Sorry new to all of this.
Whenever I try using 'Lb' as a range (from 0 to 15000 with load step of 1000) that I want the program to calculate for each, errors keep showing, and it won't continue with the calculations.
Thanks in advance.
%CALCULATIONS OF THE LATERAL TORSIONAL BUCKLING
%---------------
Cb = 1;
Lb = 0:1000:15000;
if (Sxt/Sxc >= 0.7)
FL = 0.7*Fy;
elseif (Sxt/Sxc < 0.7)
if (Fy*Sxt/Sxc >= 0.5*Fy)
FL = Fy*Sxt/Sxc;
elseif (Fy*Sxt/Sxc < 0.5*Fy)
FL = 0.5*Fy;
end
end
%CALCULATIONS OF THE LIMITING LATERALLY UNBRACED LENGTH FOR THE LIMIT STATE
%OF YIELDING, mm
Lp = 1.76*ry*sqrt(E/Fy);
%CALCULATIONS OF THE LIMITING UNBRACED LENGTH FOR THE LIMIT STATE
%OF INELASTIC LATERAL TORSIONAL BUCKLING, mm
Lr = 1.95*rt*(E/FL)*sqrt((J/(Sxc*h0))+sqrt(((J/(Sxc*h0))^2)+(6.76*(FL/E)^2)));
%CALCULATIONS OF THE NOMINAL MOMENT (Lp < Lb <= Lr)
if (Iyc/Iy > 0.23)
R1 = Mp/Myc;
elseif (Iyc/Iy <= 0.23)
R1 = 1;
end
for Mn2 = Cb*((R1*Myc)-(((R1*Myc)-(FL*Sxc))*((Lb-Lp)/(Lr-Lp))))
if (Mn2 < R1*Myc)
disp('Mn2 = Cb*((R1*Myc)-((R1*Myc)-((FL*Sxc)*((Lb-Lp)/(Lr-Lp)))))')
Mn2 = Cb*((R1*Myc)-(((R1*Myc)-(FL*Sxc))*((Lb-Lp)/(Lr-Lp))));
elseif (Mn2 >= R1*Myc)
disp('Mn2 <= R1*Myc')
Mn2 = R1*Myc;
end
end
%CALCULATIONS OF THE NOMINAL MOMENT (Lb > Lr)
if (Iyc/Iy <= 0.23)
R1 = 1 & 'J = 0';
end
R2 = sqrt(1+(0.078*(J/(Sxc*h0))*(Lb/rt)^2));
for Mn3 = Cb*pi*pi*E*Sxc*R2/(Lb/rt)^2
if (Mn3 < R1*Myc)
disp('Mn3 = Cb*pi*pi*E*Sxc*R2/(Lb/rt)^2')
Mn3 = Cb*pi*pi*E*Sxc*R2/(Lb/rt)^2;
elseif (Mn3 >= R1*Myc)
disp('Mn3 = R1*Myc')
Mn3 = R1*Myc;
end
end
if Lb <= Lp
disp('Mn = Mn1')
Mn = Mn1
else if Lb > Lp && Lb <= Lr
disp('Mn = Mn2')
Mn=Mn2
else Lb > Lr
disp('Mn = Mn3')
Mn=Mn3
end
end
plot(Lb,Mn)
Ahmed Sayedhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17317395-ahmed-sayedtag:ww2.mathworks.cn,2005:Question/5009672020-01-19T13:24:44Z2020-01-19T23:38:29Zhow can i make this loop?hi friends im new in matlab could you please help me in this problem.
I have an equations A ; A=x*a-b
x=[1 2 5 8 10];
i want to put x values into equation A one by one to solve it, which i mean x1=1, to solve A1 and x2=2 to solve A2 and so on.
after that i want to use the results that i found in this equation B= (A1...An / c).
thanksMamad Mamadihttps://ww2.mathworks.cn/matlabcentral/profile/authors/14468931-mamad-mamaditag:ww2.mathworks.cn,2005:Question/4977212019-12-22T13:32:28Z2020-01-19T23:33:28Zmerge images from diffrent folderHi,I need a code that merges 2 folders Jpg images that inside each of the folders 120 images,the format that I need to merge is on by on (1 from folder1 by 1 from folder2, 2 from folder 1 by 2 from folder 2, so on.) and pastes the merged images into a separate folder(new path).
Thank for help.Hamid Ebrahimihttps://ww2.mathworks.cn/matlabcentral/profile/authors/17138242-hamid-ebrahimitag:ww2.mathworks.cn,2005:Question/5009942020-01-19T18:38:50Z2020-01-19T23:25:46ZMatrix sequence manipulation for multiple value assignmentIs there a quick (& simple) way to do the following without a loop? Not even sure why I don't want loops but still figured it'd be nice to know if there was a way. Feels like something obvious I'm just not thinking of..
I have an array and a matrix of indices, e.g.
A = zeros(20, 1);
idxes = [1, 5; ...
10, 13; ...
19, 20];
and I'd like to convert it such that the following is achieved without hardcoding in the indices:
A([1:5, 10:13, 19:20]) = 1;
Equivalent solution with a loop:
for i = 1:size(idxes, 1)
A(idxes(i, 1):idxes(i, 2)) = 1
end
Kevin Chenhttps://ww2.mathworks.cn/matlabcentral/profile/authors/6124791-kevin-chentag:ww2.mathworks.cn,2005:Question/5009702020-01-19T14:31:33Z2020-01-19T23:25:43ZMake entries of first row and column of matrix all equal to zero. I'm trying to create an nxn matrix that has all entries in the first row and column equal to zero, and also all of the diagonal entries need to be equal to zero. The other entries are random 1's and 0's. I have so far made the diagonals equal to zero but am struggling with making the first row and column equal to zero. Below is what I have so far:
n = 10;
B = randi([0,1],n,n);
v = zeros(1,n);
B = B + diag(v-diag(B));
ThanksCiara McHughhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17274312-ciara-mchughtag:ww2.mathworks.cn,2005:Question/5010142020-01-19T23:22:13Z2020-01-19T23:24:20ZComparing natural frequency by Rayleigh Ritz method(RRM) and assumed mode method(AMM) for simply supported beam with point massesI am trying to get similar results from RRM and AMM for simply supported beam with point masses. But I am getting totaly different result from both cases. Please help me in pointing out error in codes. Below is image representing loading condition and code.
clc
clear
%Program to compute Natural frequency using AMM
L=5; b=0.05; E=69e9; rho=2500; % Material Propertise
syms x ld
h=0.2; %Beam height
m1=200; m2=90; m3=50; m4=30; m5=10; %Point Masses
Ar=h*b; % Beam Area
I=(1/12)*b*(h)^3; %Beam Inertia
phi=[sin(pi*x/L) sin(2*pi*x/L) sin(3*pi*x/L) sin(4*pi*x/L) sin(5*pi*x/L) ...
sin(6*pi*x/L) sin(7*pi*x/L) sin(8*pi*x/L)];
dphi=diff(phi,x);
ddphi=diff(dphi,x);
for i=1:7
for j=1:7
im=rho*Ar*int(phi(i)*phi(j),x,0,L)...
+m1*subs(phi(i)*phi(j),x,0.2*L)+m2*subs(phi(i)*phi(j),x,0.4*L)...
+m3*subs(phi(i)*phi(j),x,0.5*L)+m4*subs(phi(i)*phi(j),x,0.6*L)...
+m5*subs(phi(i)*phi(j),x,0.8*L);
M(i,j)=im;
ik=E*I*int(ddphi(i)*ddphi(j),x,0,L);
K(i,j)=ik;
end
end
A=K-(ld*M);
p=coeffs(det(A),ld);
l=roots(p);
%End of AMM
% Code for RRM
L=5; N=11; b=0.05; E=69e9; rho=2500; % Material Propertise as per paper
syms x
h=0.2; m1=200; m2=90; m3=50; m4=30; m5=10; %Design parameters
Ar=h*b; % Beam Area
I=(1/12)*b*(h)^3; %Beam Inertia
% Mass and Stiffness matrix
for i=1:N
for j=1:N
im=double(int(rho*Ar*sin(i*pi*x/L)*sin(j*pi*x/L), x, 0, L)...
+m1*sin(i*pi*0.2)*sin(j*pi*0.2)+m2*sin(i*pi*0.4)*sin(j*pi*0.4)...
+m3*sin(i*pi*0.5)*sin(j*pi*0.5)+m4*sin(i*pi*0.6)*sin(j*pi*0.6)...
+m5*sin(i*pi*0.8)*sin(j*pi*0.8));
ik=double(int(E*I*sin(i*pi*x/L)*sin(j*pi*x/L)*(pi/L)^4*(i*j)^2, x, 0, L));
K(i,j)=ik; %Stiffness matrix
M(i,j)=im; %Mass matrix
end
end
%Natural Frequency and modal vector
A=M\K;
[v,e]=eig(A);
w=double(sqrt(e));
C=length(v);
%End of RRMAniket Bharamgondahttps://ww2.mathworks.cn/matlabcentral/profile/authors/16166538-aniket-bharamgondatag:ww2.mathworks.cn,2005:Question/5010132020-01-19T23:14:41Z2020-01-19T23:14:41ZRecolouring Sentinel2 multispectral imageHello,
I am trying to recolour an image composed of the red, green and blue channels of Sentinel 2 imagery (Bands 4, 3 and 2, respectively). I have processed this imagery in the SNAP toolbox and exported in netCDF4-BEAM format.
Firstly, I read in the required image bands and create the RGB image:
address = %file location on computer;
ncid = netcdf.open(address);
bands{1} = transpose(im2double(netcdf.getVar(ncid,4))); %Red channel
bands{2} = transpose(im2double(netcdf.getVar(ncid,3))); %Green channel
bands{3} = transpose(im2double(netcdf.getVar(ncid,2))); %Blue channel
Image = cat(3,bands{1},bands{2},bands{3}); %RGB image, datatype of double
When I try to visualise the image with imshow(Image), the result is near monochromatic. I understand this is due to correlation between channels and so I wish to recolour the image.
What is the best way to do this?
I have tried to use the code below, however this makes no difference:
stretchedImage = imadjust(Image,stretchlim(Image));
I have also investigated the image histograms however I don't understand why there is a difference between histogram(Image) and imhist(Image). I think the differences in the outputs of these may be related to my issues with strethlim, hopefully you can help shine a light on this for me!
Many thanks.Aidan Woodhttps://ww2.mathworks.cn/matlabcentral/profile/authors/9032996-aidan-woodtag:ww2.mathworks.cn,2005:Question/3645512017-11-01T04:00:00Z2020-01-19T23:12:53ZWhy is MATLAB unable to run the MATLABWindow application on Linux?Why is MATLAB unable to run the MATLABWindow application on Linux, with the following warning?
>> simulink
Warning: MATLABWindow application failed to launch. Unable to launch the MATLABWindow application
MathWorks Support Teamhttps://ww2.mathworks.cn/matlabcentral/profile/authors/4622813-mathworks-support-teamtag:ww2.mathworks.cn,2005:Question/5008672020-01-18T13:56:59Z2020-01-19T23:00:47ZMatlab gives no result when I use the ODE (Ordinary Differential Equations)When trying to find the symbolic solution in the following code, I got a warning and empty sym!
syms y(t) y0 Dy0
A=1;
B=2;
Dy = diff(y,t);
D2y = diff(y,t,2);
ode = diff(y,t,2)-A*(y)^2-B^2*y==0;
cond1 = y(0) == 1;
cond2 = Dy(1) == 0;
conds = [cond1 cond2];
ySol(t) = dsolve(ode,conds);
ySol = simplify(ySol, 'Steps',20)
disp(ySol(t))
Warning: Explicit solution could not be found.
> In dsolve (line 201)
In symbolic_Fun (line 11)
ySol(t) =
[ empty sym ]
[ empty sym ]
What was my mistake?
Please advise.Samer Atawnehhttps://ww2.mathworks.cn/matlabcentral/profile/authors/14055129-samer-atawnehtag:ww2.mathworks.cn,2005:Question/5009922020-01-19T18:24:25Z2020-01-19T23:00:13ZNon-linear Multivariate regression using genetic algorithmI would like to perform non-linear multivariate regression using genetic algorithm in matlab.
I have five independent variables and one response. How can I do non-linear regression by minimizing the mean square error in matlab using genetic algorithm?
R = f (x1, x2, x3, x4)
I want to fit the data to the equation similar to the following:
Thus, my objective is to find the constants C1, C2, C3,..., C21 using the GA in matlab by minimizing the difference between the actual response and the response from the model.Tad2020https://ww2.mathworks.cn/matlabcentral/profile/authors/17317080-tad2020tag:ww2.mathworks.cn,2005:Question/5010062020-01-19T20:57:05Z2020-01-19T22:51:38ZGetting the coordinates of vertices of an A4 sheet with coins on it, for its further projective transformation and coin detectionI need to transform my tilted image in a way I can find coins on an A4 paper. So far, I have been getting four coordinates of edges of my paper by manually selecting them with ginput.
targetImageData = imread('coin1.jpg');
imshow(targetImageData);
fprintf('Corner selection must be clockwise or anti-clockwise.\n');
[X,Y] = ginput(4);
Is there a way to automate this process, say, apply some edge detector and then find coordinates of each vertex and then pass them as the coordinates needed for transformation?
Baldr Odinsonhttps://ww2.mathworks.cn/matlabcentral/profile/authors/17056864-baldr-odinsontag:ww2.mathworks.cn,2005:Question/5010072020-01-19T21:13:25Z2020-01-19T22:46:24ZPleaaaaaaaase i need help !!!!I want to solve this error in simulink.
""Derivative of state '1' in block 'Moteur4/Integrator' at time 0.0039708154447165821 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances) "
Component: Simulink | Category: Block error
yousra yahiahttps://ww2.mathworks.cn/matlabcentral/profile/authors/11672404-yousra-yahiatag:ww2.mathworks.cn,2005:Question/5010112020-01-19T22:38:14Z2020-01-19T22:38:14ZPrediction function code? What is the MATLAB code to find the optimal ˆθ for the prediction function fθ such that θ = argmin θ LLS(θ)?Bao Lehttps://ww2.mathworks.cn/matlabcentral/profile/authors/7609984-bao-letag:ww2.mathworks.cn,2005:Question/5008022020-01-17T20:43:13Z2020-01-19T22:21:19ZHow can I write a function for this I finally wrote a simple code to plot two slope lines but the problesm is when I run it the next slope line begins a bit high then the first one. How can I fix that like the graph belowe?
K1 = 3;
K2 = 8;
Idff1 = 20;
endline=100;
XIntersect=50;
IB =[];
ID = [];
for Ibias=0:endline
if Ibias<=XIntersect
Idiff = Idff1 + K1 * Ibias;
ID=[ID, Idiff];
IB = [IB, Ibias];
else
Idiff = K2 * Ibias;
ID=[ID, Idiff];
IB = [IB, Ibias];
end
end
plot(IB, ID);
Samanhttps://ww2.mathworks.cn/matlabcentral/profile/authors/2714358-samantag:ww2.mathworks.cn,2005:Question/4788192019-09-04T07:41:33Z2020-01-19T22:08:59ZRemove baseline wander from ECGI am using the AD8232 and the Arduino pro mini 328-3V. I want to remove the motion artifacts from my signal. I am using matlab for the signal processing and this code for the serial communication with arduino. How can I do the motion artifacts removal?
clc
close all
clear all
if ~isempty(instrfind)
fclose(instrfind);
delete(instrfind);
end
%close all
clc
disp('Serial Port Closed')
s = serial('COM5','BaudRate',9600);
fopen(s);
fprintf(s,'*IDN?');
i = 1;
while true
x(i) = str2double(fscanf(s));
i = i + 1;
plot(x)
pause(0.1)
endAnna Karimahttps://ww2.mathworks.cn/matlabcentral/profile/authors/16117637-anna-karimatag:ww2.mathworks.cn,2005:Question/5010082020-01-19T21:36:36Z2020-01-19T21:36:36ZIOT4SH01DS problem Thingspeak-automatic parameter resetHi, I have a big problem, I perfectly made the device parameters work and set and connected to the ThingViever app, but as soon as I write L'apikey and I enable Thingspeak the IOT4SH01DS device correctly sends about 4 times the temperature to the app and after you it disconnects from the network and all its settings return as factory.
Also the access password that I tried to change returns to the factory one (Littlepig).
Until he transmits all the settings remain correct, as soon as I enable Thinghspeak after a while the settings that I had modified for its correct functioning return to the factory settings.
What could be the problem?
Being in a remote area where there is no internet, the device is connected to a Telenor router wifi data modem with a IOT Thingmobile sim card that connects to the wind network.
Thanks.Rosario Rosariohttps://ww2.mathworks.cn/matlabcentral/profile/authors/17299241-rosario-rosario