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Shawn Miller


Active since 2015

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What is the kernel that MATLAB currently uses for its Symbolic Math Toolbox?
Is the kernel still Maple or does MATLAB currently use its own built kernel?

meer dan 8 jaar ago | 1 answer | 0

1

answer

Question


How good does double() convert symbolic result to numerical result?
How precise does double() guarantee in conversion? I have this concern when I found my symbolic expression result has very "giga...

meer dan 8 jaar ago | 2 answers | 0

2

answers

Question


How can I improve my code as below? I constructs an operator and repetitively call this operator, then I store the n times results in a vector.
My code now suffers from slow speed when g is a complex function or when I specify n as a relatively large integer. functio...

meer dan 8 jaar ago | 1 answer | 0

1

answer

Question


How do I preallocate symbolic matrix?
I got the warning of preallocation when I tried to change the size of my 1*n symbolic array (elements are symbolic expressions) ...

meer dan 8 jaar ago | 1 answer | 0

1

answer

Question


How do I create a matrix of symbolic function elements and also able to access the element in the matrix using row and column index?
I'd like to conduct matrix operation to symbolic functions. For instance, a row vector of symbolic functions times a column symb...

meer dan 8 jaar ago | 1 answer | 0

1

answer

Question


I wrote 2 snippets as below, they both try to find minimum value, but one repetitively uses function handles and the other uses a sub function. It turns out the speed are very different? Why?
Two snippets are as follow (they are not my original codes and are used for illustration only), the input y is just an array, fo...

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


In fmincon function, how can I impose non-strict constraints?
In fmincon, I know MATLAB can set constraints like a+b<=1 and a<=1, but what about a+b<1 and a<1?

bijna 9 jaar ago | 3 answers | 0

3

answers

Question


What does command 'rng default;' do?
What is the difference with and without this command?

bijna 9 jaar ago | 1 answer | 3

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answer

Question


If in one .m file, I write a nested function inside the main function, then I wonder if this nested function can call a function in another .m file?
I know that local functions cannot call exterior functions (i.e., functions in other .m files) but the main function can, howeve...

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


Why I got the error "Undefined operator '*' for input arguments of type 'function_handle"?
My code: f=@(x)x+1 g=@(x)x*f+4 g(1)

bijna 9 jaar ago | 1 answer | 1

1

answer

Question


Why I got a complex number rather than a real number in the program as below?
q=@(x)(x-1.0).^(1.0./5.0).*5.0+5.0; q(rand);

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


How do I create a 2^n by n matrix that the rows of the matrix enumerate all the possibilities for a n digit binary number?
For example, for n=3, there are 8 rows, and they are 000,100,010,001,110,101,001,111 (may not in this order). Any fast way to re...

bijna 9 jaar ago | 2 answers | 0

2

answers

Question


I met this problem when I was using fmincon(). I try to optimize a function handle at starting point 8, but my function handle has structure "log(exp(-100*x))", this leads to -inf rather than -100*x. How can I overcome this problem?
In my case, I got "Error using barrier (line 22) Objective function is undefined at initial point. Fmincon cannot continue." It ...

bijna 9 jaar ago | 3 answers | 0

3

answers

Question


MATLAB failed to convert symbolic matrix into numeric matrix using double() function, anyone knows what happened?
I did some arithmetic using Symbolic Math Toolbox and got a 2 by 2 matrix. Due to the analytic arithmetic, the symbolic matrix's...

bijna 9 jaar ago | 0 answers | 0

0

answers

Question


How do I convert multivariate function handle to symbolic function? Anyone has any ideas?
My function handle is as follows, g=@(p)p(1)+p(2) I can compute using function handle using something like g([1,2])...

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


How do I evaluate matrix function in symbolic format as follows?
h_matrix = @(x)(x*pascal(3)); sym_matrix = sym(h_matrix) When I use sym_matrix(2) I got an error. My question i...

bijna 9 jaar ago | 0 answers | 0

0

answers

Question


Is it true that one can solve numeric problems with Symbolic Math Toolbox since all computations using symbols are performed analytically rather than numerically?
For example, if one wants to calculate derivative, some numeric functions in MATLAB may handle this using finite differencing. H...

bijna 9 jaar ago | 2 answers | 0

2

answers

Question


How do I suppress the scale factor of a matrix?
In matlab, if the largest element of a matrix is larger than 10^3 or smaller than 10^-3 , MATLAB applies a common scale factor f...

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


Suppose the user inserts an integer n and a date string '1/1/2015' (stands for Jan 1 2015), then how do I find the date that is n days before Jan 1 2015?
It seems minus sign doesn't work. Any date function can help?

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


What may be the best way to order columns of a matrix?
I'd like to order each column for a matrix so that the smallest number is replaced with 1, the second smallest number is replace...

bijna 9 jaar ago | 1 answer | 0

1

answer

Question


How do I access to the database of Microsoft SQL Server from Matlab using ODBC?
I built a data source from Microsoft SQL Server in ODBC and attempted to connect to the data source using Database Explorer in M...

ongeveer 9 jaar ago | 0 answers | 0

0

answers

Question


How do I deal with the Error: "Undefined function 'importfile' for input arguments of type 'char'."?
I got this error after importing text data by generating a function and entered in command window something like "matrix=importf...

ongeveer 9 jaar ago | 0 answers | 0

0

answers

Question


Where's the bug with my auxiliary function?
My code is as follows, it includes a main function (FindVolatility) and a local function (selectOutput). The idea here is I'd li...

ongeveer 9 jaar ago | 1 answer | 0

1

answer

Question


How do I plot 3-dimentional graph of the following function? Can Plot3 function do this?
fun=@(x,y)100*(y-x^2)^2+(1-x)^2;

ongeveer 9 jaar ago | 1 answer | 0

1

answer

Question


Where's the bug in the following codes?
fun=@(x,y)100*(y-x^2)^2+(1-x)^2; x=-10:1:10; y=-10:1:10; [z,val]=fminsearch(fun,3,3);

ongeveer 9 jaar ago | 2 answers | 0

2

answers

Question


How do I run codes in environments other than MATLAB default folder?
I met the problem when I tried to run the following code written in a script file on my desktop, [xasterisk,value]=fminsea...

ongeveer 9 jaar ago | 1 answer | 0

1

answer

Question


Why I can't get my output? What's wrong with line 13?
<</matlabcentral/answers/uploaded_files/38000/Screen%20Shot%202015-10-05%20at%207.03.29%20PM.png>>

ongeveer 9 jaar ago | 1 answer | 0

1

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Question


I can't find >> symbol in my command window and whenever I type Enter key, it goes to the next line, why?
<</matlabcentral/answers/uploaded_files/37991/Screen%20Shot%202015-10-05%20at%202.51.26%20PM.png>>

ongeveer 9 jaar ago | 1 answer | 0

1

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Question


How can I find the roots of implicit function using fzero function?
I have written a function on MATLAB, say z=fun(x,y), here fun is an implicit function. But my question is how do I find x given ...

ongeveer 9 jaar ago | 2 answers | 0

2

answers