Community Profile

photo

Walter Roberson


43.900 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

  • First Review
  • Most Accepted 2018
  • 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
  • Knowledgeable Level 4
  • First Answer
  • Solver

View details...

Contributions in
View by

Answered
how to store large data during the execution of a program without getting out of memory
You will need to go through calculating the all partitions and writing them to a file, but keeping only a limited working set in...

alrededor de 1 hora ago | 1

| accepted

Answered
Trouble reading the file with strread and textscan
DataDate=dir('C:**file path in included here**/'); for viv=1:length(DataDate)-3 That code is incorrect. It is an attempt to sk...

alrededor de 2 horas ago | 0

Answered
Variable 'nb11' originally saved as a NaiveBayes cannot be instantiated as an object and will be read in as a uint32.
The class NaiveBayes is not available when you load the .mat . The NaiveBayes class was removed a few years ago. https://www.m...

alrededor de 3 horas ago | 0

Answered
shift the first 5 characters of str to the end using loops
You need to create an output vector the same size as the input vector. Then copy from location 6 of input to location 1 of outpu...

alrededor de 3 horas ago | 0

Answered
How to quickly find the first NaN?
You could adapt https://www.mathworks.com/matlabcentral/fileexchange/24641-vectorized-find-with-first-option to do the nan tes...

alrededor de 11 horas ago | 0

Answered
Valid indices are restricted in parlor loop
You cannot do that. Output arrays must be indexed in very simple ways, never as a range computed from the loop variable. You ...

alrededor de 11 horas ago | 0

Answered
Formula retrieval in .m files
You may wish to use Live Scripts instead of .m files. .m files never store output.

alrededor de 11 horas ago | 0

Answered
How to make empty array of specific size?
https://www.mathworks.com/matlabcentral/fileexchange/31362-uninit-create-an-uninitialized-variable-like-zeros-but-faster

alrededor de 11 horas ago | 0

Answered
how to load the data from strut
In the case where it is already loaded into Cell1 then output_matrix = [structfun(@(S) S.V(1), Cell1(:)), structfun(@(S) S.V(en...

alrededor de 15 horas ago | 0

Answered
Image Processing need to make an image circular
No. There are no data structures in MATLAB that are circular. You have two choices: Masking (alphadata) Use a cell array wit...

alrededor de 15 horas ago | 0

| accepted

Answered
How to have arbitrary markers in 'scatter'
For numerals and characters, text() them into place. For general shapes, you will need to create one or more patch() objects.

alrededor de 16 horas ago | 1

| accepted

Answered
What is the order when calling a directory?
MATLAB uses whatever order is returned by the operating system. It happens that in MS Windows, and MacOS, and Linux, that the o...

alrededor de 16 horas ago | 0

Answered
How to add a new column in table?
YourTablename.GenderCode = strcmp(YourTablename.gender, 'M')*2 - 1; %+1 for M, -1 otherwise

1 día ago | 1

| accepted

Answered
color Image filtration.
Is it possible to convert an RGB image into gray and keep one or two color? Yes, provided the result is to be RGB. For exampl...

1 día ago | 0

Answered
How to obtain the optimal parameter values for an objective function at certain values of objective function while using the fminunc function for optimization?
You would not use any minimizer for that. You would use fsolve() or vpasolve(), as in F = @(z) ht(z) - predetermined_value) pa...

1 día ago | 0

Answered
How to convert this formula to matlab language
a = mod(atan2(y-1/3,x-1/3), 2*pi)

1 día ago | 0

Answered
Why my coding keep running non stop?
You might have a bug in your code. Your program might just take a long time to complete. You might have run out of memory and ...

1 día ago | 0

Answered
how to run function 1000 times to find minimum
N = 1000; all_scores = zeros(1,N); all_groupings = cell(1,N); for iter = 1 : N [all_scores(iter), all_groupings{N}] = ge...

1 día ago | 1

Answered
Array indices must be positive integers or logical values.
pfx(x)= ((9000*x^2)-(111210*x)+77091)/500000; does not define a formula relating a function name pfx and an input value x. Inst...

1 día ago | 0

| accepted

Answered
Please, I need a CascadeBackstepping.m to solve obtain the optimal control for a cascade system of ODE.
That model does not use any MATLAB code. It consists of integrators and gain blocks and scopes and goto & from blocks. It has no...

1 día ago | 0

Answered
While Loop, question how to implement it
n=100; x=rand(1,n); k=1; while k<n && x(k) <= 0.95 k=k+1; end disp([num2str(k), ‘ is the index of the first element in ...

1 día ago | 0

| accepted

Answered
Moving 3D patch object along a trajectory
There are three ways of doing this. Create a patch and record its handle. At each time step, update the patch XData and YData ...

1 día ago | 0

| accepted

Answered
Argument of a function includes another function
[leftbound, rightbound, whatever_nf_stands_for] = bisect(@fofx, some_a, some_b, tolerance_to_use);

1 día ago | 0

Answered
Summation of Random Numbers
I would use a while loop. while summation <= x %add a random integer to the summation end

1 día ago | 0

| accepted

Answered
How do I only take the first 1000 elements of a vector?
NameOfVariable(1:1000)

1 día ago | 0

| accepted

Answered
For loops and If statements not working correctly
https://www.mathworks.com/matlabcentral/answers/480004-need-help-with-taking-an-array-inside-a-for-loop-and-plotting-it#answ...

1 día ago | 0

Answered
Please help me !!! Error using * Inner matrix dimensions must agree. Error in GRAFICA_TOTAL_2 (line 40) Volum= (2*T.^2*q1+q2*T.^3*((1/2-(A1*(A2-A3))/2*C*Ro*G(A1+A2-A3))))
Volum= (2*T.^2*q1+q2*T.^3*((1/2-(A1*(A2-A3))/2*C*Ro*G(A1+A2-A3)))) q2 is 1 x 301. T is 1 x 301. The * operator is algebraic mat...

1 día ago | 1

| accepted

Answered
read 20 images in ordered manner
See the File Exchange contribution https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort Or, ...

1 día ago | 0

Answered
Distance between point and an array.
pdist2()

1 día ago | 0

Answered
error using imfinfo()
Images in memory such as your compareimages do not have a "bitdepth", and cannot be queried with imfinfo() Before you while lo...

1 día ago | 1

Load more