3,035 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

how to add all 2d matrices in a 4D matrix???

sum(sum(your_matrix,4),3) or sum(reshape(your_matrix,10,50,[]),3)

how to add all 2d matrices in a 4D matrix???

sum(sum(your_matrix,4),3) or sum(reshape(your_matrix,10,50,[]),3)

약 2시간 ago | 0

Answered

Save values in each iteration

The loops aren't needed. E.g., Ccl = 21; % Number of column elements gene = 5; % Number of times the column is generated min...

Save values in each iteration

The loops aren't needed. E.g., Ccl = 21; % Number of column elements gene = 5; % Number of times the column is generated min...

약 13시간 ago | 0

Answered

How to find the angle between two quaternions?

For example purposes I am using the coordinate frames as ECI and BODY Q1 = quaternion from ECI->BODY1 Q2 = quaternion from ECI...

How to find the angle between two quaternions?

For example purposes I am using the coordinate frames as ECI and BODY Q1 = quaternion from ECI->BODY1 Q2 = quaternion from ECI...

4일 ago | 1

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Answered

for loop, conditional operator

You are creating the variable filling_degree_regionI_new inside a condition if statement. If the condition is never met, the va...

for loop, conditional operator

You are creating the variable filling_degree_regionI_new inside a condition if statement. If the condition is never met, the va...

4일 ago | 0

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Answered

Get next or prior single precision value MATLAB function ?

The designers of IEEE floating point were brilliant. The next largest value (in magnitude) is always obtained by just adding 1 t...

Get next or prior single precision value MATLAB function ?

The designers of IEEE floating point were brilliant. The next largest value (in magnitude) is always obtained by just adding 1 t...

9일 ago | 0

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Answered

Arrays from c to matlab.

v is pointer-to-double, *v is double. Everywhere inside generation() that you use v it needs to be *v instead.

Arrays from c to matlab.

v is pointer-to-double, *v is double. Everywhere inside generation() that you use v it needs to be *v instead.

10일 ago | 0

Answered

Shuffling and Using a Set of Six 52-Card Decks

It is not entirely clear what you want. Maybe this instead of the loop? shuffledcard = decksofcards(randomcards);

Shuffling and Using a Set of Six 52-Card Decks

It is not entirely clear what you want. Maybe this instead of the loop? shuffledcard = decksofcards(randomcards);

12일 ago | 0

Answered

How to add new elements in a big array

Maybe assign into elements of N with indexing: N(j) = length(group);

How to add new elements in a big array

Maybe assign into elements of N with indexing: N(j) = length(group);

21일 ago | 1

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Answered

filling each row of a matrix using values from a vector

Assuming x starts as a 4x4 matrix (instead of a 3x4 matrix): x(sub2ind(size(x),(1:numel(u))',u)) = 1;

filling each row of a matrix using values from a vector

Assuming x starts as a 4x4 matrix (instead of a 3x4 matrix): x(sub2ind(size(x),(1:numel(u))',u)) = 1;

22일 ago | 0

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Answered

Convert double array into column vector

Maybe one of these? reshape(f,1,[]) f(:).'

Convert double array into column vector

Maybe one of these? reshape(f,1,[]) f(:).'

22일 ago | 0

Answered

uint16 to uint8

u16 = your uint16 variable u8 = typecast(u16,'uint8');

uint16 to uint8

u16 = your uint16 variable u8 = typecast(u16,'uint8');

22일 ago | 0

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Answered

API changes in R2019a?

I don't know if this is the cause of your problems, but there was a change to the low level mxArray variable structure in R2019a...

API changes in R2019a?

I don't know if this is the cause of your problems, but there was a change to the low level mxArray variable structure in R2019a...

22일 ago | 0

Answered

complex number inside cell array

This might be done better with a loop, but here is a method using cellfun c = your cell array containing complex numbers resul...

complex number inside cell array

This might be done better with a loop, but here is a method using cellfun c = your cell array containing complex numbers resul...

22일 ago | 0

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Answered

RK4 orbit problem

Couple of things: 1) You have picked the most convoluted method of coding your equations. Having four separate variables for yo...

RK4 orbit problem

Couple of things: 1) You have picked the most convoluted method of coding your equations. Having four separate variables for yo...

22일 ago | 1

Answered

Portable declaration of REAL variables in mex gateway for Fortran

The REAL(kind(0.0D0)) vs REAL*8 discussion (and INTEGER*4 vs INTEGER etc) is a compiler issue, not a mex issue. As long as your...

Portable declaration of REAL variables in mex gateway for Fortran

The REAL(kind(0.0D0)) vs REAL*8 discussion (and INTEGER*4 vs INTEGER etc) is a compiler issue, not a mex issue. As long as your...

23일 ago | 0

Answered

The return type of mxIsDouble, mxIsSingle, and mxIsClass (mex for Fortran)

Do what the documentation says and use INTEGER*4. Yes, it is non-standard but you are very unlikely to run into a compiler that...

The return type of mxIsDouble, mxIsSingle, and mxIsClass (mex for Fortran)

Do what the documentation says and use INTEGER*4. Yes, it is non-standard but you are very unlikely to run into a compiler that...

23일 ago | 0

Answered

How can I generate random single precision (float32) numbers ?

For the generic answer with all bit patterns possible and selected with equal probability (including inf & nan & denorm) your "b...

How can I generate random single precision (float32) numbers ?

For the generic answer with all bit patterns possible and selected with equal probability (including inf & nan & denorm) your "b...

25일 ago | 1

Answered

How can I show the 4-byte hex representation of a single precison float value?

s = your single float number h = dec2hex(typecast(s,'uint32'),8) And the reverse is s = typecast(uint32(hex2dec(h)),'single')...

How can I show the 4-byte hex representation of a single precison float value?

s = your single float number h = dec2hex(typecast(s,'uint32'),8) And the reverse is s = typecast(uint32(hex2dec(h)),'single')...

28일 ago | 0

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Answered

Error using mex: undefined reference for user build package

Try looking in the MATLAB/R2019a/extern/lib folder for versions of these files appropriate for your system. They might have slig...

Error using mex: undefined reference for user build package

Try looking in the MATLAB/R2019a/extern/lib folder for versions of these files appropriate for your system. They might have slig...

약 1달 ago | 0

Answered

Problem with MexFunction and MexGetPr

Impossible to answer without seeing the code for the functionsum( ) function. Maybe you could post that? Maybe all you need to...

Problem with MexFunction and MexGetPr

Impossible to answer without seeing the code for the functionsum( ) function. Maybe you could post that? Maybe all you need to...

약 1달 ago | 0

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Answered

Unexpected numerical error in built-in cross product

When I calculate things from scratch, everything works to the expected precision. E.g., run this code: % From post rTAN = [6.2...

Unexpected numerical error in built-in cross product

When I calculate things from scratch, everything works to the expected precision. E.g., run this code: % From post rTAN = [6.2...

약 2달 ago | 2

Answered

MEX crashes when called twice in succession (Same input)

Here is one cause of a crash: mwIndex *subs; subs[0]=1; subs[1]=1; You are dereferencing an uninitialized pointer on that se...

MEX crashes when called twice in succession (Same input)

Here is one cause of a crash: mwIndex *subs; subs[0]=1; subs[1]=1; You are dereferencing an uninitialized pointer on that se...

약 2달 ago | 0

Answered

Change sign of descending values

Is this what you want? x = your vector of values d = [1;diff(x)]; x(d<0) = -x(d<0);

Change sign of descending values

Is this what you want? x = your vector of values d = [1;diff(x)]; x(d<0) = -x(d<0);

약 2달 ago | 1

| accepted

Answered

how to iterate a matrix for multiple times

E.g., here is a possible outline n = 30; % the number of iterations M = rand(5,5); % some initial matrix for k=1:n M = 2...

how to iterate a matrix for multiple times

E.g., here is a possible outline n = 30; % the number of iterations M = rand(5,5); % some initial matrix for k=1:n M = 2...

약 2달 ago | 1

| accepted

Answered

Using the dms2degree Command Sequentially to Populate an Array using a Sub-routine

With a for-loop, you need to use A in all of your indexing and use the [ ] brackets to form a vector input (and spell the functi...

Using the dms2degree Command Sequentially to Populate an Array using a Sub-routine

With a for-loop, you need to use A in all of your indexing and use the [ ] brackets to form a vector input (and spell the functi...

약 2달 ago | 0

Answered

Write a function called valid_date that takes three positive integer scalar inputs year, month, day. If these three represent a valid date, return a logical true, otherwise false. The name of the output argument is valid.

Looks like you are taking the same class as Rahul. Rather than repeat my answer here, I will simply direct you to the link: ht...

Write a function called valid_date that takes three positive integer scalar inputs year, month, day. If these three represent a valid date, return a logical true, otherwise false. The name of the output argument is valid.

Looks like you are taking the same class as Rahul. Rather than repeat my answer here, I will simply direct you to the link: ht...

약 2달 ago | 0

| accepted

Answered

I need some help in seeing where I am going wrong and how to proceed with writing a particular funciton for a MATLAB course I am taking please.

Some issues: n is a fixed input ... you should not be changing n inside your function. Get rid of that n = n + 1 statement. T...

I need some help in seeing where I am going wrong and how to proceed with writing a particular funciton for a MATLAB course I am taking please.

Some issues: n is a fixed input ... you should not be changing n inside your function. Get rid of that n = n + 1 statement. T...

약 2달 ago | 1

| accepted

Answered

Use of int vs size_t in mex compilation of C-function dgemm.

If you are linking to the MATLAB supplied BLAS/LAPACK libraries, then all of the integer types being used for arguments to these...

Use of int vs size_t in mex compilation of C-function dgemm.

If you are linking to the MATLAB supplied BLAS/LAPACK libraries, then all of the integer types being used for arguments to these...

약 2달 ago | 0

| accepted