Walter Roberson
Last seen: Today
49.902 total contributions since 2011I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location.
Walter Roberson's Badges
Reach 100000 reputation points. Honors the first contributor to reach this milestone, Walter Roberson
Awarded to Walter Roberson on 14 Aug 2020
The contributor whose answers received the most acceptances in 2019
Awarded to Walter Roberson on 01 Jan 2020
The contributor whose answers received the most acceptances in 2018
Awarded to Walter Roberson on 18 Jan 2019
Solve a problem for the first time
Awarded to Walter Roberson on 10 Jun 2017
Publish your first comment or rating
Awarded to Walter Roberson on 09 Oct 2019
The contributor whose answers received the most acceptances in 2017
Awarded to Walter Roberson on 02 Jan 2018
Contribute at least one answer each month for 36 consecutive months
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2016
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2015
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2011
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2012
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2013
Awarded to Walter Roberson on 20 Jul 2017
Accept 50 answers given by other contributors
Awarded to Walter Roberson on 20 Jul 2017
Reach 25000 reputation points
Awarded to Walter Roberson on 20 Jul 2017
Answer 50 questions that were unanswered for more than 30 days
Awarded to Walter Roberson on 20 Jul 2017
How to draw the contour lines in MATLAB.
data = readmatrix('Sai.xlsx'); contour(data, 0.1:0.1:1) colorbar
ongeveer 3 uur ago | 0
Supress Warning in a Loop
X=X-inv(j)*f; replace with if rank(j)<length(j) X = nan; else X = X - j\f; end
ongeveer 4 uur ago | 1
How to reorder a vector one cell at a time?
Okay, so the problem is that the rules are not exactly as you describe. The algorithm Start at the top of the column, and reme...
ongeveer 13 uur ago | 0
how to solve an equation iteratively?
syms x eqn1 =200 == x*(1-(0.4*(x-1))/sqrt(2.8*2.4*x+0.4))^(-2.8/0.4); sol = solve(eqn1, x); sol = sol(imag(sol) == 0) vpa(so...
ongeveer 16 uur ago | 0
| accepted
Inverse a cell of matrices
T1inv = cellfun(@inv, T1, 'uniform', 0); However, most of the time you should avoid using inv() . It is not common that you nee...
ongeveer 16 uur ago | 0
error: Unrecognized function or variable 'y', using ode45
function main a = 0.01725*exp(2660/300); E = 2660; T0 = 300; Cao = 2; cpa = 20; cpb = 20; nao = 2*1200; nbo = 2*1200; ...
ongeveer 17 uur ago | 2
| accepted
while loop for changing vairable
theta = [-90:5:90] M = sind(theta); N = cosd(theta); T = arrayfun(@(m,n)[m^2 n^2 0 0 0 2*m*n; n^2 m^2 0 0 0 -2*...
ongeveer 18 uur ago | 0
| accepted
How to skip vpasolve empty sym inside a loop
Store the result of vpasolve into a variable. Test to see if it is empty before storing into the matrix.
ongeveer 18 uur ago | 0
| accepted
Index exceeds array bounds... need some help please!
i= [1:100]; x(i)= 100; You initialize 100 elements for i=[1:100] Tf(i+1)=x(i+1); You try to access 100+1 elements Also...
ongeveer 19 uur ago | 0
covert data as matrix
Q =(unifrnd(0,1,5,15)) save('Q.txt', 'Q', '-ascii', '-double') !cat Q.txt
1 dag ago | 1
| accepted
Why does symbolic integration return the wrong answer for this integral?
syms x a expr = 1/(1-x)^2 F = int(expr, x, 0, a) subs(F,a,x)
1 dag ago | 2
| accepted
Plot function adding line from last point in row to origin
In order to see that plot with multiple lines, your y_nudged must be 2D. The following code takes that into account. xt = x_nud...
1 dag ago | 0
Creating grid with incremental numbers around specific coordinate
N = 5; r = 2; c = 3; temp = true(N,N); gr = bwdistgeodesic(temp, c, r) + 1
1 dag ago | 0
| accepted
Table properties giving error
You have a third-party function named split on your MATLAB path. which -all split
1 dag ago | 0
| accepted
need help with this summation
zeta = reshape(linspace(0,2), 1, [], 1); %row fo = reshape(logspace(-2,0,50), [], 1, 1); %column n = reshape(1:2:101, 1,...
1 dag ago | 0
'Matrix dimensions must agree' error in matlab app designer
function botonButtonPushed(app, event) if app.menu.Value=="engranaje" app.caja.Value=1 ...
1 dag ago | 0
| accepted
why matlab calls (pixel per inch "PPI") a (dot per inch "DPI") ?
the DPI term indicates to a something related to printing terminology which is dot ink per inch unit, Although it did certainly...
1 dag ago | 0
| accepted
How can I represent the following equation in code?
w = linspace(-5,5); hejw = abs(besselh(1, exp(1j*w))); mask = 0.7943 <= hejw & hejw <= 0.8913; plot(w, hejw, 'k-'); hold...
1 dag ago | 0
how to save the output image
infile = 'ISIC_0024336.jpg'; citra=imread(infile); figure, fig1=imshow(citra); load mri V = squeeze(citra); citra3=montag...
1 dag ago | 0
| accepted
matlab gives wrong graphical display info
https://www.mathworks.com/help/matlab/creating_guis/dpi-aware-behavior-in-matlab.html
1 dag ago | 0
| accepted
Calculation of a precise point after indefinite integral
syms Sy IXX syms d R y_a = @(d,R) R*sin(d) ; q_o_a(d, R) = -(Sy/IXX)*int(y_a(d,R)*R*t,d) ; q_1 = q_o_a(pi/2, R) ; ...
1 dag ago | 0
how to estimate/evaluate the integral of a constant value function?
syms t a b real f = piecewise(0 < t & t < 1, 5, 0) int(f, t, a, b)
1 dag ago | 0
| accepted
MATLAB no longer displaying fractions in symbolic calculation.
sympref('FloatingPointOutput', false)
1 dag ago | 1
| accepted
An efficient way to compute many sums with different number of terms
cumsum() and index it by the values
1 dag ago | 0
Determine Critical Points Numerically
EA=30000; alpha=30; beta=30; gamma=180-(alpha+beta); a=20; n=6; L_ab=a; L_bc=(a*sind(alpha))/(sind(beta)); L_ac=(a*sind(...
1 dag ago | 0
Can we plot streamilnes, isotherms and isocontour plots in MATLAB?
streamline: https://www.mathworks.com/help/matlab/ref/streamline.html Isotherms would be https://www.mathworks.com/help/matlab...
1 dag ago | 0
| accepted
Need to figure out how to find the average.
You are intended to loop over the rows for this task, not process the entire data first. Extract a row. Take nanmean of the row...
1 dag ago | 0
How do I only show 1 output instead of all the outputs as a result of the matrix
num = randi(10,3,2); [row1,col1]=size(num); foundit = false; for a=1:row1 for b=1:col1 if num(a,b) == 7 ...
1 dag ago | 1
| accepted
What is wrong with this optimization code using fmincon?
OBJFUN = @(A) 1/N *sum ( ( ( GeRT_model(A) .- GeRT_exp ) ./ GeRT_exp ).^2 ); ^^ ...
1 dag ago | 0
How do I find the average/mean of each row if the data has 150 rows and 3 columns?
A = 'measurements'; That assigns the character vector ['m' 'e' 'a' 's' 'u' etc] to A, not the content of a variable named measu...
1 dag ago | 0
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
Select web siteYou can also select a web site from the following list:
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)