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 can I use a for loop to create new variables?

You might consider automatic array expansion. E.g., look at this result: t = 0:0.01:10; % row a = [0.1 1 3]'; % column y = e...

How can I use a for loop to create new variables?

You might consider automatic array expansion. E.g., look at this result: t = 0:0.01:10; % row a = [0.1 1 3]'; % column y = e...

circa 17 ore ago | 1

Answered

Can someone convert this to matlab code?

So, you don't need any loops for this. Just use the automatic array expansion feature. E.g., take a look at what happens with ...

Can someone convert this to matlab code?

So, you don't need any loops for this. Just use the automatic array expansion feature. E.g., take a look at what happens with ...

circa 17 ore ago | 0

Answered

Two variables need to be connected to one struct variable.

What about something like this: Results.First_Name = first_name{target}; Results.Last_Name = last_name{target}:

Two variables need to be connected to one struct variable.

What about something like this: Results.First_Name = first_name{target}; Results.Last_Name = last_name{target}:

circa 18 ore ago | 0

| accepted

Answered

How would I write the function of f(x)=sin(x)*exp(-x/10)

The multiply. E.g., f = @(x) sin(x) .* exp(-x/10); You don't need it on the divide because you are dividing by a scalar.

How would I write the function of f(x)=sin(x)*exp(-x/10)

The multiply. E.g., f = @(x) sin(x) .* exp(-x/10); You don't need it on the divide because you are dividing by a scalar.

circa 21 ore ago | 1

Answered

Error using ^ (line 51) Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

This is often caused by using a matrix or vector in an equation when you thought you were using a scalar. E.g., take these lines...

Error using ^ (line 51) Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

This is often caused by using a matrix or vector in an equation when you thought you were using a scalar. E.g., take these lines...

1 giorno ago | 0

Answered

Reading 64 bit words

Try reading and keeping the type as uint64 (using the *) instead of converting to double: word = fread(fid,1,'*uint64');

Reading 64 bit words

Try reading and keeping the type as uint64 (using the *) instead of converting to double: word = fread(fid,1,'*uint64');

1 giorno ago | 0

Answered

mex, error C3861: "mxGetDoubles": Cannot find the identifier, "mxGetUint8s": Cannot find the identifier ？

Those functions are for the R2018a memory model API. For that, you need to add the -R2018a option flag: mex myfile.cpp -R2018a...

mex, error C3861: "mxGetDoubles": Cannot find the identifier, "mxGetUint8s": Cannot find the identifier ？

Those functions are for the R2018a memory model API. For that, you need to add the -R2018a option flag: mex myfile.cpp -R2018a...

1 giorno ago | 0

| accepted

Answered

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

You are missing an ending parenthesis, and also you probably need to use element-wise multiply: u3 = exp(-0.89*t) .* (1.75*cos(...

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

You are missing an ending parenthesis, and also you probably need to use element-wise multiply: u3 = exp(-0.89*t) .* (1.75*cos(...

1 giorno ago | 0

| accepted

Answered

Solving a nonlinear ODE

Step 1: Solve your ODE for the highest order derivative, in this case Rdoubledot (on paper) Rdoubledot = stuff (you figure thi...

Solving a nonlinear ODE

Step 1: Solve your ODE for the highest order derivative, in this case Rdoubledot (on paper) Rdoubledot = stuff (you figure thi...

5 giorni ago | 0

Answered

Computational Complexity of matrix multiplication

This question is perhaps more involved than it looks on the surface, because by default MATLAB doesn't store the imaginary part ...

Computational Complexity of matrix multiplication

This question is perhaps more involved than it looks on the surface, because by default MATLAB doesn't store the imaginary part ...

5 giorni ago | 0

| accepted

Answered

error:All functions in a script must be closed with an 'end'.( kindly see the code and help me to remove the error)

Looks like maybe this for iy = 1:H end for ix = 1:W should be just this for iy = 1:H for ix = 1:W Side Note: This would b...

error:All functions in a script must be closed with an 'end'.( kindly see the code and help me to remove the error)

Looks like maybe this for iy = 1:H end for ix = 1:W should be just this for iy = 1:H for ix = 1:W Side Note: This would b...

6 giorni ago | 0

Answered

Using the euler method

p(ip) is the value of p at time t(ip). p isn't a function that you are passing time into like you are doing with p(t(ip)). So ...

Using the euler method

p(ip) is the value of p at time t(ip). p isn't a function that you are passing time into like you are doing with p(t(ip)). So ...

10 giorni ago | 0

Answered

Finding Nonzero Elements in a Vector

You need to wrap this statement with an if-test and only execute it if v(CurrentPosition) is non-zero: prod = prod * v(CurrentP...

Finding Nonzero Elements in a Vector

You need to wrap this statement with an if-test and only execute it if v(CurrentPosition) is non-zero: prod = prod * v(CurrentP...

10 giorni ago | 0

Answered

Markov Chain probability steady state

Hint: The probability of moving from one state to another state in n steps is P^n

Markov Chain probability steady state

Hint: The probability of moving from one state to another state in n steps is P^n

13 giorni ago | 0

Answered

Factorial without the Command

You could use either use a loop to multiply all of the numbers from 1 to n, or use recursion to multiply n by the factorial of n...

Factorial without the Command

You could use either use a loop to multiply all of the numbers from 1 to n, or use recursion to multiply n by the factorial of n...

14 giorni ago | 0

Answered

Inputs a Vector and Returns the Second Smallest Element

Your algorithm always replaces Smallest and SecondSmallest at each iteration. Does that make sense? E.g., if the current Smalle...

Inputs a Vector and Returns the Second Smallest Element

Your algorithm always replaces Smallest and SecondSmallest at each iteration. Does that make sense? E.g., if the current Smalle...

14 giorni ago | 0

Answered

Hex to float like python struct.unpack()

Could be a Big Endian vs Little Endian thing. E.g., inserting a swapbytes( ) step: >> hex = 'C956F53D' hex = 'C956F53D' ...

Hex to float like python struct.unpack()

Could be a Big Endian vs Little Endian thing. E.g., inserting a swapbytes( ) step: >> hex = 'C956F53D' hex = 'C956F53D' ...

14 giorni ago | 0

Answered

Python to MATLAB accuracy

Probably not. The trailing bits of floating point calculations in general can't be trusted. It you change the order of the calc...

Python to MATLAB accuracy

Probably not. The trailing bits of floating point calculations in general can't be trusted. It you change the order of the calc...

14 giorni ago | 0

| accepted

Answered

solving coefficient with linear algebra

You basically have this: [ONES_COLUMN, X_COLUMN, Y_COLUMN] * p = DATA You know all the CAPS stuff. So just use the standard l...

solving coefficient with linear algebra

You basically have this: [ONES_COLUMN, X_COLUMN, Y_COLUMN] * p = DATA You know all the CAPS stuff. So just use the standard l...

16 giorni ago | 0

Answered

Composite Functions with a function with two ranges

For example, take the first one: (g o f)(x) This is just g(f(x)) which is g(x^2) Assuming we are talking only about real in...

Composite Functions with a function with two ranges

For example, take the first one: (g o f)(x) This is just g(f(x)) which is g(x^2) Assuming we are talking only about real in...

20 giorni ago | 0

Answered

im trying to create a while loop for random numbers and it says if its even or odd

Change this while times < 20 to this while Ecounter < 20 and change this Ecounter = 0+1; to this ...

im trying to create a while loop for random numbers and it says if its even or odd

Change this while times < 20 to this while Ecounter < 20 and change this Ecounter = 0+1; to this ...

21 giorni ago | 0

Answered

The Body Mass Index, or BMI

Just get rid of these lines: function BMI=findbmi(Weight,Height)

The Body Mass Index, or BMI

Just get rid of these lines: function BMI=findbmi(Weight,Height)

21 giorni ago | 1

Answered

From where is this exp in syms calculus?

The solution space has multiple values, not just one. The solver has parameterized the solution space for you. There are multi...

From where is this exp in syms calculus?

The solution space has multiple values, not just one. The solver has parameterized the solution space for you. There are multi...

28 giorni ago | 0

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Answered

simulate a dice throw

doc randi E.g., for a single throw you could use randi(6)

simulate a dice throw

doc randi E.g., for a single throw you could use randi(6)

29 giorni ago | 1

| accepted

Answered

Why do I get "Array indices must be positive integers or logical values" error when using?

k is 3.5 So y(k-1) is y(2.5) and y(k-2) is y(1.5). The indexes are not positive integers, hence the error. Maybe you meant ...

Why do I get "Array indices must be positive integers or logical values" error when using?

k is 3.5 So y(k-1) is y(2.5) and y(k-2) is y(1.5). The indexes are not positive integers, hence the error. Maybe you meant ...

29 giorni ago | 0

| accepted

Answered

How to fill mxArray with mxGetComplexDoubles?

No, this would not be expected to work. In the first place, you need to use mxDOUBLE_CLASS to create the mxArray, not mxSINGLE_...

How to fill mxArray with mxGetComplexDoubles?

No, this would not be expected to work. In the first place, you need to use mxDOUBLE_CLASS to create the mxArray, not mxSINGLE_...

30 giorni ago | 0

| accepted

Answered

The spacecraft free-fall math model

See this link for an example of the parachute problem: https://www.mathworks.com/matlabcentral/answers/516385-code-not-working-...

The spacecraft free-fall math model

See this link for an example of the parachute problem: https://www.mathworks.com/matlabcentral/answers/516385-code-not-working-...

30 giorni ago | 0

Answered

Satellite Orbit, Friction Acceleration Function

See this link for an example that uses atmospheric drag with a satellite (in this case a satellite falling to Earth): https://w...

Satellite Orbit, Friction Acceleration Function

See this link for an example that uses atmospheric drag with a satellite (in this case a satellite falling to Earth): https://w...

30 giorni ago | 0

Answered

Fibonacci Series Using Recursive Function

All of your recursive calls decrement n-1. Eventually you will wind up with the input n=0 and just return v=0, which is not wha...

Fibonacci Series Using Recursive Function

All of your recursive calls decrement n-1. Eventually you will wind up with the input n=0 and just return v=0, which is not wha...

circa un mese ago | 0