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Walter Roberson


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50,914 2011 年以降の合計貢献数

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

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Regexp match a string only if it is not preceded by another string
pattern = '(?<!blowing )snow'

約14時間 前 | 1

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GUI Static Text didnt show anything
We cannot tell for sure what size x is. If inputmatrices is a multi-line edit field in which there was one entry per line, then ...

約16時間 前 | 0

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Stuck at a command input
You accidentally created your own load.m that is interfering with using MATLAB's load() function. Also, it appears that you mig...

約16時間 前 | 0

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Naming variables from one column Import file
No. When you are importing variables manually using the import tool, then you are stuck with what the import tool provides. If ...

約16時間 前 | 1

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how to get values of a square matrix at an degree from center & how to get end points of y
improfile() if you have the Image Procesing Toolbox. If not, then the code for improfile() is based upon interp2()

約16時間 前 | 1

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Errors with fprime of Newton's method
There are two completely different diff() functions in MATLAB. The main one works with numeric data, and for it, diff(x) is x(2...

約16時間 前 | 0

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A Mathematica script that deals with multidimensional arrays needs to be converted to Matlab. How to do it?
https://library.wolfram.com/infocenter/MathSource/577/ is a convertor from Mathematica code to MATLAB code.

約17時間 前 | 0

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Fmincon - Variable dependent constraints
lb = [1, 1/20, 2/20]; ub = [2, 2/10, 2/5]; A = [ 1/20, -1, 0 -1/10, 1, 0 0, 2, -1 -1/5, 0, 1 ...

約18時間 前 | 2

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num2str error in converting an integer
You used the function name num2srt but the real function name is num2str

約18時間 前 | 0

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Subtracting complex number from a discrete signal
A = 123 B = -0.000053 + 0.0030995i C = A - B In other words, you do not need to do anything special to convert the signal ...

約19時間 前 | 0

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Matlab struct with names and sizes of the mat.file
Use whos() with the '-file' option and extract the required data from that.

約19時間 前 | 0

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writing/exporting a plot into a file
Newer releases: see exportgraphics() https://www.mathworks.com/help/matlab/ref/exportgraphics.html Older releases: see getfram...

約20時間 前 | 0

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textscan: Instantaneous out of memory error when accessing very large file (only with newest Matlab versions)
specify the encoding on your fopen() so that the i/o library does not have to read through the entire file to ddetermine the enc...

約23時間 前 | 0

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Need help in creating a code
function n_pop=cencus(n_year) ^^^^^^ Spelling.

約23時間 前 | 1

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hardware support package not supporting matlab verson
Use the Support Package for NVIDIA Jetson CPUs -- which specifically documents Nano support. https://www.mathworks.com/help/sup...

1日 前 | 0

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solving state space using ode45
You are trying to run sys() without passing in values for t or i . sys() then fails when it needs to use one of the input variab...

1日 前 | 0

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Extracting index of specified date from datetime array
S = datetime({'2015-05-03 23:59:56' '2015-05-03 23:59:56' '2015-05-03 23:59:56' '2015-05-03 23:59:56' '2015-05-03 23:59:57' ...

1日 前 | 1

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Solve two simultaneous equations for a set value of y
y = 1.4; syms x A = (1/x)*(2/(y+1)*(1+(y-1)/2*x^2))^((y+1)/(2*(y-1))); P = (((y+1)/2*x^2)/(1+(y-1)/2*(x^2)))^(y/(y-1))*((1)/(...

1日 前 | 1

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Having scale that changes on same axis
MATLAB does not have any support for changing a scale for only part of an axes. You will need to use a second plot. Some people...

1日 前 | 0

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Jacobi iteration what the wrong of my code please help
size(d) is 4 x 4, so size(inv(d)) is 4 x 4. size(b) is 1 x 4. You cannot use matrix multiplication * operator between a 4 x 4...

1日 前 | 0

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How do I reshape a vector into a zero-diagonal matrix?
x = [1;2;3;4;5;6;7;8;9;10;11;12]; nx = numel(x); n = ceil(sqrt(nx)); if nx ~= n*(n-1) error('vector is wrong size to ma...

1日 前 | 0

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Plotting specific data points from a vector/double
plot(face_orig([1:104, 107:255])); However, this would give you a result as-if the entry at 107 were from 105. You should more ...

1日 前 | 0

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How to draw these signals on matlab
plot(rand(1,10)); ylim([-0.1 1.1]) yticks([.1 .5 .9]) yticklabels({'$$Output$$', '$$\begin{array}{r}non-\\Inverting\\Input\en...

1日 前 | 1

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How to plot Fourier transform of the signal from a text file (*.txt) ?
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/614995/DATA.txt'; data = readtable(filename, 'readva...

1日 前 | 0

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Light direction in surfl
The bright area is mostly because of the specular lighting that is being introduced. doc specular says R = specular(Nx,Ny,Nz,...

1日 前 | 0

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how to solve "error using griddata" in order to plot an efficiency map
% test arrays have corresponding size speedRPM = 1:200; % 1x200 TorqueNm = 1:100; % 1x100 EffeciencyPer = speedRPM + TorqueNm...

1日 前 | 0

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make our own signum
Under the interpretation that nan values are not less than 0 (they are not greater than 0 either) output = (value < 0) .* -2 + ...

1日 前 | 0

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How can I merge 100 .xlsx files into one file?
%the below code does NOT assume that the input is numeric. %the code DOES assume that all files have the same datatype for %co...

1日 前 | 0

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Using XY Data from this example? Help please
After the call to geometryFromEdges(model,g); then model.Geometry.Vertices will give you the initial geometric coordinates a...

1日 前 | 0

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How do I subplot from a large file? Note..any .txt file of any large figures can be given. So please solve generally.
You could calculate N more cleanly as N = size(r, 1); T and c and r will each be a single column. You take the number of row...

2日 前 | 0

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