Community Profile

photo

Walter Roberson


Last seen: Today
48.026 total contributions since 2011

I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location.

Contact

Walter Roberson's Badges

  • Roberson Cup
  • Most Accepted 2019
  • Most Accepted 2018
  • Solver
  • First Review
  • Most Accepted 2017
  • 36 Month Streak
  • Most Accepted 2016
  • Most Accepted 2015
  • Most Accepted 2011
  • Most Accepted 2012
  • Most Accepted 2013
  • Thankful Level 4
  • Grand Master
  • Revival Level 4

View all

Contributions in
View by

Answered
Infinite symsum returns symbolic number.
I do not know why that happens, but do this for a workaround: syms n x=0.5; y=1.5; f = (400/sinh(2*n*pi))*(((n*pi)*(1-(((-...

ongeveer 4 uur ago | 0

| accepted

Answered
Repeating a sequence of code multiple times in a for loop with random intervals in between
rec=@(x) (x)>=0.75; for counter = 1 : 150 j = (0 : 0.01 : 29); k = sin(j); f = rec(k); [a,b]=find(f~=0); ...

ongeveer 5 uur ago | 0

Answered
Using matlab's spmd to compute simple triple integral is giving me incorrect solution, any thoughts on what I am doing wrong?
You integrate the first section of x with the first section of y and the first section of z, and the second section of x with th...

ongeveer 5 uur ago | 0

Answered
Make a matrix with matching numbers per column from a bigger one
mask = A(:,1) == 2011 & A(:,5) == 101; B = A(mask,:);

ongeveer 5 uur ago | 1

| accepted

Answered
Generate a 100000x100000 matrix that takes less time and memory
a=zeros(ni,ni,'uint8'); You are already using only one byte per entry. If you were to create logic that packed 8 adjacent ent...

ongeveer 5 uur ago | 0

Answered
Start an external program (.exe) inside a matlab window
External processes always run as a separate window. However for non-graphic processes, you can control the standard output and s...

ongeveer 5 uur ago | 0

Answered
Imaginary Number Notation/ Formatting Real and Complex Results
An exact 0 imaginary part shows up as +0i if it is being displayed as part of a matrix of values in which some are not complex, ...

ongeveer 5 uur ago | 1

| accepted

Answered
how to put them text lines into loop to reduce the coding line?
text(repmat(1.688, 1, 8),[0.038, 0.028, 0.02, 0.13, 0.0076, 0.004, 0.0015, 0], {'ola', 'ola1', 'ola2', 'ol3', 'ol4', 'ola5', 'ol...

ongeveer 17 uur ago | 1

| accepted

Answered
plot with equals in matlab
yy=sin(x)+0.2*sin(2x)-0.3*sin(3x); MATLAB has absolutely no implied multiplication anywhere. Not even in the symbolic toolbox. ...

ongeveer 17 uur ago | 1

Answered
determine whether or not the following signals are periodic
plot(t,x) That should be plot(t,y) the second time. sol=mean(diff(locs)*0.1) why 0.1 ? Finding the average difference betwee...

ongeveer 17 uur ago | 0

Answered
Adding edges to a Graph
Graph = addedge(Graph, TobeAdded(1:end-1), TobeAdded(2:end))

ongeveer 18 uur ago | 1

Answered
how can I write more than 1 objective in linprog line
You cannot have multiple objectives using linprog(), not even in the case where the constraints are the same for all objectives....

ongeveer 18 uur ago | 0

Answered
Lagrangian interpolation index exceeds matrix dimensions
>> fid = fopen('force.m','r'); n = fscanf(fid,'%f',1) n = [] >> type force.m F = [0.107 100;0.172 200;0.238 300;...

ongeveer 18 uur ago | 0

Answered
How to add offset to image?
clc; clearvars; close all; x=zeros(224,224); x(10:20,10:20)=randn(11,11); h=real(ifft2(x)); %h=real(ifft2(x))+5; "5" is for...

ongeveer 19 uur ago | 0

Answered
How to convert .slx model to .m or .p or . mlx or .mex?
You would need Simulink Coder, which would generate C or C++ code that you would call from Python.

ongeveer 20 uur ago | 0

Answered
Convert cell array of syms to double
double([X{:}]).'

ongeveer 20 uur ago | 0

| accepted

Answered
Need Help with surface plot. Getting error that dimensions of S do not match
clear all clc close all tspan=logspace(-10,6,(16*10)+1) y0=[1;0;0]% IC of Concentration Ea1=linspace(10,15); Ea2=lin...

ongeveer 24 uur ago | 0

Answered
Writing data in columns from "for loop" to ".txt" file
The only way to write column-by-column to a text file is to arrange the code so that at each step, it reads the existing content...

ongeveer 24 uur ago | 1

| accepted

Answered
Assign multiple elements of one cell array to another
B(:,:,2) = A;

1 dag ago | 0

| accepted

Answered
Please explain the training set for neural network
how to get numdate ? In the example there "Electricity Load Forecasting using Neural Networks" then you have to look at the fir...

1 dag ago | 0

| accepted

Answered
Getting error: Second argument must be a variable or a nonnegative integer specifying the number of differentiations.
It is not possible to differentiate with respect to a function. You have to make a substitution and hope that the system remain...

1 dag ago | 1

| accepted

Answered
How do I plot an Inverse Laplace? (symbolic to vectorized equations)
As is not uncommon, the inverse laplace of that particular function is defined in terms of a quantity evaluated over the sum of ...

1 dag ago | 1

| accepted

Answered
column operator erases complex property
For reasons I do not understand, z(:) is being treated as an expression. If you make z larger but complex, then reshape(z,[],1) ...

1 dag ago | 0

| accepted

Answered
solving ode45 with mutliple classes
You are trying to return a cell from your odefun. ode45 requires that you return a numeric column vector with the same number of...

1 dag ago | 0

Answered
How to display vector elements in a structure field?
MATLAB does not give any control over the number of elements displayed by @struct/display Some similar matlab routines choose...

1 dag ago | 1

| accepted

Answered
draw a plot-graph
If F(n) is not a constant, then you have the problem that you have three independent variables and one dependent variable. That ...

1 dag ago | 1

Answered
Error using eig. Input matrix contains NaN or Inf.
Revised code1.m. Please re-check whether the data is indeed lat/lon or is cartographic (km) datavariety = 1; %1: data is lat/l...

1 dag ago | 1

| accepted

Answered
Plot not looking like equation should.
point (0,y) should be joined to point (C-y, 0) for some constant C eg 0 1 to 5 0, 0 2 to 4 0, 0 3 to 3 0, 0 4 to 2 0, 0 5 to ...

2 dagen ago | 0

Answered
Multiple Iterations over a system of linear equations
u(1:1:N) = 0; u(N+1) = 1; So all of your u values are 0 except for the last one k(j) = ((1-G(t))*u(j))+((G(t)/2)*(u(j+1)+u(j-...

2 dagen ago | 0

| accepted

Answered
Dot indexing is not supported for variables of this type when trying to write value into static text box
function text7_CreateFcn(hObject, eventdata, handles) value = 1; set(hObject, 'String', num2str(value))

3 dagen ago | 0

Load more