# Walter Roberson

I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location. I am currently caught up to T0099000; if you are waiting on a reply from me for an older issue, please send me a reminder.

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**Content Feed**

Error: "Difference order N must be a positive integer scalar"

There are two different functions named diff(). Symbolic diff is calculus differentiation. It needs a symbolic expression (sym...

25 minutes ago | 1

Error "Undefined function or variable"

Perhaps num_of_samples is less than 1. Perhaps data_files(data_counter).Video is empty for all num_of_samples different videos....

3 hours ago | 0

What should go in a next-generation MATLAB X?

Currently the model of MATLAB is that it always evaluates from left to right [*] finding the left-most unprocessed sub-expressio...

1 day ago | 1

Event function for ODE solver with binary values

It is not illegal, but it makes it more difficult to find the boundary. In the case of x < something resulting in a 0 that is t...

1 day ago | 0

Only graphing two out of three of my graphs

N = 1200; %arbitrary deltast = 2e-5; t1 = 0:deltast:deltast*(N-1); xlow=0.02394; zeropos=find(t1==xlow) Empty. No ex...

1 day ago | 0

find the values of a variable for which the determinant of the matrix become zero?

syms w real a = 2e-3; X = 150-3; h = 20e-3; b = 20e-3; A = b*h; l = 500e-3; I = (b*(h^3))/12; p = 2700; E= 69e9; v12 =...

2 days ago | 0

Removing one length from a matrix

C = A .* reshape(B, size(A,1), size(A,2), size(A,3), []); This assumes element-by-element multiplication, not matrix multiplica...

2 days ago | 0

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code is giving error ,unable to get output graphs...

This is closer. I had to speculate about what the validation was intended to do, and about what proper coordinates were. There...

2 days ago | 0

I have a Matrix , and I want to multiply this Matrix with something so I can get zeros

null(P1) Note: this may have different number of columns depending on the values in P1. Each column of the result will be inde...

2 days ago | 0

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Matlab warning when using log

axis([0 7*10^5 0 4.77./5]) set(gca,'YScale','log','XScale','log') %this is the reason for all of it. Do not use an axis lim...

2 days ago | 1

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Function readtable: how to insert the value of a variable double in the directory

basedir = fullfile('C:\Users', 'hp', 'OneDrive', 'Project', 'Results'); x = 'rig53'; y = 97; filename = fullfile(basedir, x, ...

2 days ago | 0

No constructor 'Stateflow.Annotation' with matching signature found

I confirm that the statement does not work in R2017b, which is the first release that has a documentation page for it. The R201...

2 days ago | 0

operations on two different matrices

D0 j=1,8 A(1, j)=D(2,j+1) end do Acol = size(A,2); A(1,:) = D(2,2:Acol+1); vec = DD1(1,:); A1(idx,:) = repmat(vec,numel(id...

2 days ago | 0

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Can I add display on MATLAB app interface which can showcase error or any statements there itself ?

Sure. As long as you have code that detects the error and updates the display. However, if your question is about somehow "red...

2 days ago | 0

Issue with int() function

The int() work out independent of theta. cos() integrated over 0 to 2*pi is sin(2*pi)-sin(0) which is 0.

3 days ago | 0

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vpaintegral() not showing output

You cannot. vpaintegral always gives up immediately when there are unbound variables besides the variable of integration. vpa...

3 days ago | 0

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Live Editor output fractions to decimals

sympref to change the default output style.

3 days ago | 0

Compare two strings with some restrictions

In https://www.mathworks.com/matlabcentral/answers/1452949-get-the-last-for-digits-as-the-time-this-message-was-sent#answer_7870...

3 days ago | 0

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error when using Matlab generated a function for read a file

That error is saying that you tried to run the importfile() function without passing it any file name. Perhaps you just pressed ...

3 days ago | 0

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Why is the file size different before and after applying wavelet decomposition and reconstruction to a 1D signal?

If you are comparing the size of a .mat that stores just the original signal, to the size of a .mat that stores just A1 together...

3 days ago | 0

Solving non linear equation "Circle" equations

syms xa ya R3 xc = [0; 40; 100.66]; yc = [0; 0; 49.07]; r3 = 52.59; R = [84.4; 68; R3]; eqn = (xa-xc).^2 + (ya-yc).^2 == R....

3 days ago | 1

cration of contents inside the cell array of uniform size

result = cellfun(@(C) full([(0:7).', sparse(C(:,[1 1])+1, [1*ones(1,size(C,1)), 2*ones(1,size(C,1))], C(:,[2 3]), 8, 2)]), Data,...

3 days ago | 0

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I want to plot a integral expression but it shows error as "Incorrect dimensions for raising a matrix to a power. Check that the matrix is square" Kindly help me out

syms hw sigma = 8.41/1000000; A = 4*10^(-14); C = 1.2404e+08; t = int((1/((C/sigma)*((sigma*hw)^3+(A)))),hw,0,hw); HW = [2:...

3 days ago | 0

Store data from a a loop

maxrating = 3; AAADowngrade = cell(maxrating,1); l=10; %end rating for rating = 1 : maxrating k = rating+1; %start r...

3 days ago | 0

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I am having error in this programme. i gave the call function also.

The function you are missing is on PDF page 108 of https://www.researchgate.net/file.PostFileLoader.html?id=5696da346143257e508b...

3 days ago | 1

Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 2.947558e-19. what dose it mean

https://www.mathworks.com/help/matlab/ref/rcond.html When the reciprocal condition number is very small, then the condition nu...

3 days ago | 0

my code is giving the error "not enough input arguments". How to resolve this error?(matlab2013a)

https://www.mathworks.com/help/matlab/ref/ode15i.html [t,y] = ode15i(odefun,tspan,y0,yp0) That is a minimum of four parameters...

3 days ago | 0

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How to numerically differentiate provided data?

x = [0,0.375,0.75,1.125,1.5,1.875,2.25,2.625,3]; y = [0,-0.2571,-0.9484,-1.9689,-3.2262,-4.6414,-6.1503,-7.7051,-9.275]; theta...

3 days ago | 0

Solving an equation with multiple variables in MATLAB

syms E h k L Ti Tsurr Ts x eqn = -k*(Ts - Ti)/L - h*(Ts - Tsurr) - E*x*(Ts^4 - Tsurr^4) == 0 sol_implicit = solve (eqn, Ts) s...

3 days ago | 0

Problem in solving a set of 5 odes and getting Nan values

K_M=[0 27 32 0 0]; First K_M is 0. W=6; initial_conditions=zeros(1,W-1); initial_conditions(5)=10; % ug/ml First bou...

4 days ago | 0

| accepted