2,872 total contributions since 2007

Interested in external applications, mex & engine applications with Fortran, C, C++, etc, particularly in the areas of speed improvement and memory management efficiencies.

Answered

what does this code represents? and why rand() has no value between parentheses?

rand() is the same as rand without the parentheses ... they both simply call the rand function with no input arguments. The beh...

what does this code represents? and why rand() has no value between parentheses?

rand() is the same as rand without the parentheses ... they both simply call the rand function with no input arguments. The beh...

20 hours ago | 0

Answered

Solve 10 system of ODEs with separate functions and time dependent factors

This isn't going to work. You can't use random values in the derivative function for ode45. The derivative calls that ode45 mak...

Solve 10 system of ODEs with separate functions and time dependent factors

This isn't going to work. You can't use random values in the derivative function for ode45. The derivative calls that ode45 mak...

21 hours ago | 1

Answered

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

What is size(dist) and size(v_e)? If these are row vectors, then maybe you need to do e*e' instead to get a scalar result.

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

What is size(dist) and size(v_e)? If these are row vectors, then maybe you need to do e*e' instead to get a scalar result.

22 hours ago | 0

Answered

Loop through specific strcuture field names

As Stephen says, this is going to be slow. But maybe this syntax using dynamic field names would be useful to you: R{i}.([name...

Loop through specific strcuture field names

As Stephen says, this is going to be slow. But maybe this syntax using dynamic field names would be useful to you: R{i}.([name...

23 hours ago | 0

Answered

Create new cell array based on entries of other cell arrays

Not sure if this will suffice for your needs, but a simple way to get the unique strings in alphabetical order: arr4 = unique([...

Create new cell array based on entries of other cell arrays

Not sure if this will suffice for your needs, but a simple way to get the unique strings in alphabetical order: arr4 = unique([...

2 days ago | 0

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Answered

Normalizing a complex number

It is not clear what you are trying to do. You use the word "normalize" but it looks like maybe you are just trying to find the ...

Normalizing a complex number

It is not clear what you are trying to do. You use the word "normalize" but it looks like maybe you are just trying to find the ...

3 days ago | 0

Answered

Which is more efficient: iteratively filling in a sparse matrix vs. creating a new sparse matrix every time i need to update the matrix?

Iteratively changing a sparse matrix causes the entire data set to be copied each time, so this is inherently not efficient and ...

Which is more efficient: iteratively filling in a sparse matrix vs. creating a new sparse matrix every time i need to update the matrix?

Iteratively changing a sparse matrix causes the entire data set to be copied each time, so this is inherently not efficient and ...

8 days ago | 0

Answered

I have a matrix eg [1,6,3], and i have a 31*1 cell array ,each element of cell is a matrix. My problem is i wants to extract matrix from the cell position {1*1},{6*1},{3*1} and to be stored all these in separate matrices.

E.g., is this what you want? c = your 31x1 cell array v = your vector of indexes, e.g. [1,6,3] result = c(v); % extract the c...

I have a matrix eg [1,6,3], and i have a 31*1 cell array ,each element of cell is a matrix. My problem is i wants to extract matrix from the cell position {1*1},{6*1},{3*1} and to be stored all these in separate matrices.

E.g., is this what you want? c = your 31x1 cell array v = your vector of indexes, e.g. [1,6,3] result = c(v); % extract the c...

9 days ago | 0

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Answered

Error was detected while a MEX-file was running and MATLAB is exiting because of fatal error

Can you explain what you intended with these lines for A: double **A; : A = (double**)mxGetPr(prhs[0]); If y...

Error was detected while a MEX-file was running and MATLAB is exiting because of fatal error

Can you explain what you intended with these lines for A: double **A; : A = (double**)mxGetPr(prhs[0]); If y...

9 days ago | 0

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Answered

inconsistency when comparing cell arrays with strings vs char array

This is a really good question. E.g., >> version ans = '9.4.0.813654 (R2018a)' >> strcmp("abcd","abcd") ans = logica...

inconsistency when comparing cell arrays with strings vs char array

This is a really good question. E.g., >> version ans = '9.4.0.813654 (R2018a)' >> strcmp("abcd","abcd") ans = logica...

15 days ago | 0

Answered

Voltage Measurement block: "do not delete this again". What is the story behind this?

Do not delete this "gain" ... not "again" P.S. Mathworks employees do have a sense of humor ... just not for this particular ca...

Voltage Measurement block: "do not delete this again". What is the story behind this?

Do not delete this "gain" ... not "again" P.S. Mathworks employees do have a sense of humor ... just not for this particular ca...

15 days ago | 1

| accepted

Answered

Array Indexing Logical Values

"We know that rounding the index prevents the error" So that's a big clue. "Is there a hidden decimal place not being shown to...

Array Indexing Logical Values

"We know that rounding the index prevents the error" So that's a big clue. "Is there a hidden decimal place not being shown to...

19 days ago | 0

Answered

Matlab crashes when i create output matrix in mex.

I haven't had much time to look at this in detail, but at first glance this stands out: void createTable(unsigned int *dataStre...

Matlab crashes when i create output matrix in mex.

I haven't had much time to look at this in detail, but at first glance this stands out: void createTable(unsigned int *dataStre...

25 days ago | 0

Answered

hi everybody , i have a question please , if i have X=[1:10] and Y=[-5:5] and i want to have all the point of the plane (x,y) , what can i do in matlab to extract this point to use it

Does this do what you want? [x,y] = meshgrid(X,Y); result = [x(:),y(:)]; Then iterate over the rows of result. Or you can ju...

hi everybody , i have a question please , if i have X=[1:10] and Y=[-5:5] and i want to have all the point of the plane (x,y) , what can i do in matlab to extract this point to use it

Does this do what you want? [x,y] = meshgrid(X,Y); result = [x(:),y(:)]; Then iterate over the rows of result. Or you can ju...

26 days ago | 0

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Answered

summation of sinx using summation

You are missing the alternating signs of the terms. E.g., you could put in a factor of (-1)^something to get this effect. The ...

summation of sinx using summation

You are missing the alternating signs of the terms. E.g., you could put in a factor of (-1)^something to get this effect. The ...

29 days ago | 0

Answered

How to concatenate each row of a matrix into a vector ?

result = char(A+'0');

How to concatenate each row of a matrix into a vector ?

result = char(A+'0');

29 days ago | 1

Answered

Index exceeds the number of array elements (1)

Type the following at the command line: dbstop if error Then run your code. When the error occurs, the code will pause at that...

Index exceeds the number of array elements (1)

Type the following at the command line: dbstop if error Then run your code. When the error occurs, the code will pause at that...

1 month ago | 0

Answered

How to correct "Parse" error

Don't have your function at the top of this. Put it at the end or in a separate file. E.g., t = 1; while (height ~=0) h =...

How to correct "Parse" error

Don't have your function at the top of this. Put it at the end or in a separate file. E.g., t = 1; while (height ~=0) h =...

1 month ago | 0

Answered

I have a matrix (57,3600,45), how can I create matrices with (3600,45)?

Is this what you want? k = some integer index squeeze(your_matrix(k,:,:))

I have a matrix (57,3600,45), how can I create matrices with (3600,45)?

Is this what you want? k = some integer index squeeze(your_matrix(k,:,:))

1 month ago | 0

Answered

Square root table without using arrays

You need to put the new line \n in appropriate places in your loops. In particular, you only need one new line \n printed once y...

Square root table without using arrays

You need to put the new line \n in appropriate places in your loops. In particular, you only need one new line \n printed once y...

1 month ago | 0

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Answered

Memory Size and Processor Speed

Yes you can run MATLAB on this. What tasks will you typically be using MATLAB for?

Memory Size and Processor Speed

Yes you can run MATLAB on this. What tasks will you typically be using MATLAB for?

1 month ago | 0

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Answered

How to? - Complex numbers

E.g., for an anonymous function you need to give the input argument list first. E.g., for a generic derivative function that tak...

How to? - Complex numbers

E.g., for an anonymous function you need to give the input argument list first. E.g., for a generic derivative function that tak...

1 month ago | 0

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Answered

And/or between two 3d arrays

Do you mean this? sum(array1>250 & array2>170,3);

And/or between two 3d arrays

Do you mean this? sum(array1>250 & array2>170,3);

1 month ago | 0

Answered

Function in Fortran to Funciton in Matlab

function result = F0(n,x) if( n<2 ) error('bad argument n in F0') end tox=2.0/x; bkm=F00(x); bk=F01(x); for j=1:n-1 ...

Function in Fortran to Funciton in Matlab

function result = F0(n,x) if( n<2 ) error('bad argument n in F0') end tox=2.0/x; bkm=F00(x); bk=F01(x); for j=1:n-1 ...

1 month ago | 1

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Answered

differentiating function & getting different answer

Perhaps you are shadowing the MATLAB function diff with a function of your own. Make sure diff is pointing to the MATLAB functio...

differentiating function & getting different answer

Perhaps you are shadowing the MATLAB function diff with a function of your own. Make sure diff is pointing to the MATLAB functio...

1 month ago | 0

Answered

Invalid Syntax at '='.Possibly,a ),} or ] is missing at line 6 .

The { } formulation for blocking code is not valid MATLAB syntax. To fix this: Get rid of the open brace { Replace the close b...

Invalid Syntax at '='.Possibly,a ),} or ] is missing at line 6 .

The { } formulation for blocking code is not valid MATLAB syntax. To fix this: Get rid of the open brace { Replace the close b...

1 month ago | 1

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Answered

use this vector and a mathematical expression to create the following vectors:

Yes. It works for me: >> x= [1, 2, 3, 4 ,5] x = 1 2 3 4 5 >> x1= x.*[1,128,243,64,5] x1 = 1 25...

use this vector and a mathematical expression to create the following vectors:

Yes. It works for me: >> x= [1, 2, 3, 4 ,5] x = 1 2 3 4 5 >> x1= x.*[1,128,243,64,5] x1 = 1 25...

2 months ago | 0

Answered

Extracting matrix values for an algorithm

Something like this? xy = your n x 2 array n = size(xy,1); for k=1:n % run your algorithm here with x = xy(k,1) and y = ...

Extracting matrix values for an algorithm

Something like this? xy = your n x 2 array n = size(xy,1); for k=1:n % run your algorithm here with x = xy(k,1) and y = ...

2 months ago | 1

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Answered

Basic power rule ((a^b)^c = a^(b*c)) does not work

This has been discussed in this forum before. Raising complex numbers to a power is a multi-valued operation. MATLAB picks one...

Basic power rule ((a^b)^c = a^(b*c)) does not work

This has been discussed in this forum before. Raising complex numbers to a power is a multi-valued operation. MATLAB picks one...

2 months ago | 1

Answered

Is it possible to use logical indexing to specify between a number interval and include a value outside that interval.

E.g., Mask = ismember(str,[' ','a':'z','A':'Z']); Or using your method Mask = (65<=Ustr & Ustr<=90) | Ustr == 32;

Is it possible to use logical indexing to specify between a number interval and include a value outside that interval.

E.g., Mask = ismember(str,[' ','a':'z','A':'Z']); Or using your method Mask = (65<=Ustr & Ustr<=90) | Ustr == 32;

2 months ago | 1

| accepted