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Walter Roberson


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45,731 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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How to work around the precision problem?
I worked through symbolically. Suppose that you create your x vector, starting at 0, and that each entry is theoretically perfe...

約5時間 前 | 0

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combine or merge multiple excel files into one file.
name = cell(0,0); id = cell(0,0); x2010 = []; x2011 = []; x2012 = []; x2013 = []; x2014 = []; x2015 = []; x2016 = []; x2017 = ...

約12時間 前 | 0

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Solving mach number for 5000 different iterations
%% Equations %p02/p1 ratio p02_p1_6 = p02_6./p1_6; p02_p1_8 = p02_8./p1_8; p02_p1_10 = p02_10./p1_10; p02_p1_12 = p02_12./p...

約12時間 前 | 0

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Function running slow than scripts when placed in a 'for loop'?
Generally speaking: functions have more opportunities for internal acceleration than scripts have but function calls have over...

約13時間 前 | 0

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how to synchronize structures with date fields in text format
dateinfo = cellfun(@(S) datetime({S.date}), C, 'uniform', 0); TT = cellfun(@(S, T) table2timetable(struct2table(S), 'RowTimes',...

約13時間 前 | 0

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how to obtain anonymous function after derivative ?
syms x df = matlabFunction(diff(f(x), x), 'vars', {x})

約13時間 前 | 0

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why does matlab tell me that the "chop" command doesn't exist?
MATLAB does not contain any chop() function, unless it is a method for some object that I cannot think of at the moment. Perhap...

約14時間 前 | 0

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Copyfile/ movefile when filenames are not directly available
Assuming that newFolder is the name of a variable that stores the destination folder name: copyfile(flagged(i).name, newFolder)...

約15時間 前 | 0

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How to save a symbolic equation in a txt file?
save('test.mat', 'A', 'a', 'b', 'c'); When you use syms a that is equivalent to a = sym('a'); That calls into the symbolic ...

約15時間 前 | 1

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Unable to perform assignment because brace indexing is not supported for variables of this type.
At the bottom of your loop you have data = data{i}; That replaces the cell array data that contains the cell with framegra...

約16時間 前 | 0

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How to deploy my code on raspberry pi as a standalone?
It is not possible to deploy CNN training to hardware. It is not possible to deploy augmentedImageDatastore to hardware. Your ...

約16時間 前 | 0

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Using fsolve function, I want to get only real positive roots.
You cannot constrain range to positive in fsolve(). You can add an option that will cause fsolve() to stop processing if it enc...

約16時間 前 | 1

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How to save a symbolic equation in a txt file?
If you plan to use the expression inside a numeric solver, you should use matlabFunction(), which has the advantage of convertin...

約16時間 前 | 1

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Can't open nii image with MATLAb R2017a
You need to install https://www.mathworks.com/matlabcentral/fileexchange/8797-tools-for-nifti-and-analyze-image Note: as of th...

約17時間 前 | 0

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Solve an equation and get a solution that depends on a variable
syms Nin(t) % Vin = (sign(t - 200/11)/2 + 1/2)*((11*t)/100000 - 1/500) - (11*t)/100000 + 1/500 eq1 = Nin == Constant * Vin; s...

約17時間 前 | 0

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error message"Matrix index is out of range for deletion."
Consider: vector V = [1 2 -3 -4 5] . Task: delete negative elements. for K = 1 : length(V) if V(K) < 0; V(K) = []...

約17時間 前 | 0

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Error using symengine in numerical solver
syms w_r S = vpasolve(0==(1-((length(r_dc_s)^(-0.5))*(chi2inv(0.95,length(mu))))... /(1*sqrt(w_r'*V*w_r)+((length(r_dc_s)...

約18時間 前 | 0

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Is it possibile combine an RGB image and an IR image in a FOUR-BAND tiff image?
Tiff class can be used. The IR can be placed into Extra Samples. I seem to recall that you can also directly write an array with...

1日 前 | 0

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How should the value of objective function be returned for fmincon?
f = sum((actual(:) - predicted(:)).^2);

1日 前 | 0

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Solving an optimization problem in fmincon with nonlinear constraints
Warning: Matrix is singular, close to singular or badly scaled. Results may be inaccurate. RCOND = NaN. > In ode15s (line 589)...

1日 前 | 0

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Complex number error (number will be an array)
Inside of [], anywhere that you have an element, followed by whitespace, followed by - or + followed immediately by an element w...

1日 前 | 1

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vector uses info from itself to grow without for cycle
function A = calculate_A(n) if n == 1 A = 1/2; else A_before = calculate_A(n-1); A = [A_before; (...

1日 前 | 0

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how to split a string
If the current vector is shorter than N or exactly N then add the complete current vector to the end of the cell array and retur...

1日 前 | 0

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To create a code that differentiate any function
fun = str2sym(input('fun= ', 's')); var = str2sym(input('which variable= ', 's')); y = diff(fun, var)

1日 前 | 0

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Pulling data from a for loop
T = 29; % %C Tambient = 20; % C Tfilm = (T + Tambient)/2; Tskin = nan; for t = 1:1:100 k_air_2 = (2.4131 + 0.0078 * T)...

1日 前 | 2

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How to get the mean of the function?
Mean of function F over A to B is (integral of F from A to B)/(B-A)

2日 前 | 0

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Best way to solve my implicit equation
In an interactive session: syms any of the names corresponding to variables you will need to change. Calculate lhs(eqn)-rhs(e...

2日 前 | 0

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real simple -- spreadsheet parsing
You can use extractBetween() on the string array, and double() the result

2日 前 | 0

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merge txt and num back again.
If you must use xlsread() then use the third output of xlsread(), often known as raw, which will be a cell in which each entry t...

2日 前 | 0

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functions of funtions symbolic
You cannot do that, unfortunately. symbolic functions at the MATLAB level are strictly created by evaluating a symbolic express...

2日 前 | 0

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