3.033 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 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...

1 dag 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...

1 dag 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...

6 dagen ago | 0

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.

7 dagen 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);

9 dagen 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);

18 dagen 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;

19 dagen 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(:).'

19 dagen 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');

19 dagen 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...

19 dagen 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...

19 dagen 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...

19 dagen 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...

20 dagen 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...

20 dagen 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...

23 dagen 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')...

25 dagen 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...

ongeveer een maand 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...

ongeveer een maand 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...

ongeveer 2 maanden 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...

ongeveer 2 maanden 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);

ongeveer 2 maanden ago | 1

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Answered

Trouble with declaring function output

function data = importer

Trouble with declaring function output

function data = importer

ongeveer 2 maanden ago | 1

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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...

ongeveer 2 maanden 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...

ongeveer 2 maanden 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...

ongeveer 2 maanden ago | 0

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Answered

sum of multiplication for a vector and matrix

result = sum(b*A);

sum of multiplication for a vector and matrix

result = sum(b*A);

ongeveer 2 maanden ago | 1

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...

ongeveer 2 maanden 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...

ongeveer 2 maanden ago | 0

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Answered

For loop to extract every 3rd column out of matrix and assign as variable name

Do not do this! This will only lead to headaches downstream in your code for processing these variables (you will need to use m...

For loop to extract every 3rd column out of matrix and assign as variable name

Do not do this! This will only lead to headaches downstream in your code for processing these variables (you will need to use m...

ongeveer 2 maanden ago | 1

| accepted

Answered

random generator on level of bytes

Generate random integers and then multiply them by 8 to guarantee that the result is divisible by 8. E.g., something like: max_...

random generator on level of bytes

Generate random integers and then multiply them by 8 to guarantee that the result is divisible by 8. E.g., something like: max_...

ongeveer 2 maanden ago | 2