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Walter Roberson


Last seen: Today Con actividad desde 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. I am currently caught up to T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

Programming Languages:
C, MATLAB, Shell, Perl, Fortran
Spoken Languages:
English

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Respondida
How is the streamline function implemented?
streamlines() is implemented by calling stream2() or stream3() to figure out where the lines go. Then it just draws the lines. ...

23 minutos hace | 0

Respondida
for loop inside while loop
count = 0; iters = 0; while count < 100 iters = iters + 1; a = randperm(100,20); for i=1:length(a) i...

alrededor de 1 hora hace | 0

Respondida
what does A/b mean when solving matrix Ax=b
If you have A*x = b then x = A\b is very likely what you need But if for some reason you want to know what meaning A/b would ha...

alrededor de 2 horas hace | 0

Respondida
Running Matlab in the linux background using nohup
I suspect that in your shell, matlab is an alias rather than an executable file on your path. For example on Mac, you would hav...

alrededor de 2 horas hace | 0

Respondida
How to solve the elements are different between X0 and H in quadprog
The initial value parameter, x_start in this context, must be a vector .

alrededor de 7 horas hace | 0

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Respondida
Matlab Solve and simplify functions not working
V1 = -(760*(348475767795489804396578940311480912*3^(1/2) + 168032379110159424438402050627659277))/(3*(38588796620235615516044318...

alrededor de 8 horas hace | 0

Respondida
Can Matlab Home run on a Persistent Live Ubuntu USB Stick Operating System?
It is certainly possible to install MATLAB onto a removable drive, whether that drive is spinning rust, or SSD, or USB keychain ...

alrededor de 11 horas hace | 0

Respondida
Help with matlab Homework
As I identified in https://www.mathworks.com/matlabcentral/answers/2058504-need-help-with-matlab-homework#answer_1368659 you sh...

alrededor de 12 horas hace | 0

Respondida
How to open new command window?
https://www.mathworks.com/matlabcentral/fileexchange/48593-save-entire-command-history-updated-fast can be used to save the comm...

alrededor de 16 horas hace | 0

Respondida
How can evaluate the integral (r*bessilei(1,k*r)) dr, k is a constant?
syms k r solution = int(besseli(1, k*r), r)

1 día hace | 0

Respondida
How to add calculated column to existing matrix in for loop
r2 = 40/1000; r3 = 120/1000; r4 = 70/1000; r5 = 60/1000; %t = linspace(0,5,500); t = (0:1:5); % 50 steps N = le...

1 día hace | 0

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Respondida
Why do I receive the error while running the code?
[ode1, ode2, ode3] = dsolve(eq1, eq2, eq3, 'u(x0) == u0', 'u(xn) == vn', 'w(x0) == w0', 'Dw(xn) == 0'); MATLAB is not able to s...

1 día hace | 0

Respondida
I need help learning how to input a code of subdividing intervals equally
linspace Caution: linspace takes an parameter that is the number of points involved, not the number of intervals involved. The ...

1 día hace | 0

Respondida
Is normalization necessary for input and output data in an Artificial Neural Network (ANN)? Does it impact the network's performance?
Is normalization necessary for input and output data in an Artificial Neural Network (ANN) No, it is not necessary. Does it im...

1 día hace | 0

Respondida
How to use a global variable when using ode45()?
The first parameter to the ode function, often referred to as t, is mostly not an integer (but might turn out to be an integer b...

1 día hace | 1

Respondida
Need help with Matlab homework
data = readmatrix("products inventory.xlsx"); You used readmatrix() to read from a .xlsx file. When readmatrix() works, the out...

1 día hace | 1

Respondida
Why does abs cause bad matlabfunction evaluation?
You are taking the derivative of abs(), but abs() does not have a continuous derivative. You have the sub-expression abs(((x - ...

1 día hace | 1

Respondida
Access property of class object found by "whos"
What you are looking for is VALUE = evalin(caller, s(matches).name + ".LastUpdate") We do not recommend this, however. If you...

2 días hace | 1

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Respondida
Unable to meet integration tolerances without reducing the step size
[t, u] = ode15s(@(t, u) MyODEs(t, u, Nx, dx, f, c, D), tspan, u0,options); ode15s is defined as passing a scalar value as the f...

2 días hace | 0

Respondida
Interpolation across only 1 dimension for a multi-dimensional array
Use interp1(). The first input must be a vector; the second input can be an array of any size; permute() it so that you are inte...

2 días hace | 0

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Respondida
Calculation of mortgage interest from the amount of the mortgage, annuity monthly installments and number of years
M = 100000; a = 8791.59; r = 1; syms x eqn = a == M*(x/1200*(1+x/1200)^(r*12))/((x/1200+1)^(r*12)-1) sol = solve(eqn, x); ...

2 días hace | 0

Respondida
How to deal with files in which rows have different numbers of columns
You could readcell but I wouldn't recommend it. I would suggest using textscan with appropriate format for what you are expecti...

2 días hace | 0

Respondida
Unable to perform assignment because the left and right sides have a different number of elements.
This version of the code does more work than is necessary, but has the minimal change needed to prevent the particular error you...

3 días hace | 0

Respondida
Split array into groups of close numbers
No -- because there is no rigourous meaning to what "close" means. For example, in [1 3 5 7], surely 1 is not "close" to 7, but...

3 días hace | 0

Respondida
Operator '>' is not supported for operands of type 'cell'.
filename = 'T.xlsx'; opt = detectImportOptions(filename); opt = setvaropts(opt, [2:6,13:15,18:19], 'Prefixes', "'", 'Suffixes'...

3 días hace | 0

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Respondida
Having multiple different bins in a histogram that don't overlap
Are you looking for bar with the 'stacked' option? Or are you looking for bar() with groups? Generally speaking, there are two...

3 días hace | 0

Respondida
Can we generate best fitted nonlinear equation between 4 inputs and 1 output, if we dont know the equation initially
No, you cannot. There are multiple constructive proofs that if you have a finite number of points known to finite precision, the...

3 días hace | 0

Respondida
Loading variables to a specifc workspace
How can i use the load command to load variables to a specific workspace MATLAB does not provide any way to do that. I would...

3 días hace | 0

Respondida
Please optimize this code by using a loop to display the polynomial coefficients.
fprintf('p%d=%.8f.\n', K, z(K+1)) However, you are using different widths for different coefficients. You will need to build a ...

3 días hace | 0

Respondida
FSOLVE requires all values returned by functions to be of data type double. showing while solving an algebraic equation in matlab ??
F and G are int() calls. Even if they evaluate to closed forms that were rational numbers, they have symbolic results. When you ...

3 días hace | 0

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