# T

Active since 2014

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Question

Use two bsxfun for row and column vector to span matrix without putting in memory
Hello, I have a vector A of size 1xN and a vector B of size MxN I can span a MxN matrix temp with temp=bsxfun(@times,A,B);. ...

6 years ago | 1 answer | 0

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Question

Efficiently calculate distance between moving point and fixed points
Hello, I have a grid of point coordinates xval=0:1:5000; yval=0:1:2000; zval=1; [X,Y,Z]=meshgrid(xval,yval,zv...

6 years ago | 1 answer | 0

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Question

Better interpolation of nonuniform data to uniform grid than with spline
I am resampling non-uniformly sampled data to a uniform grid with a spline interpolation. However, if the signal is of high fre...

6 years ago | 0 answers | 0

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Question

Speed up 1D spline interpolation on matrix
Hello, I have a NxM matrix named data and I need to spline interpolate each row of my matrix according to: for k=1:size(...

7 years ago | 1 answer | 0

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Question

ned2ecef without toolbox
Are there any user-made functions available somewhere that achieve the same? The lg2ct function in the Geodetic Toolbox on the ...

7 years ago | 0 answers | 0

### 0

Question

Multiply each column in MxN matrix with it's transpose to create MxMxN matrix
Hello, I have a MxN matrix, and I need to multiply each column vector that is of size Mx1 with it's transpose. This gives me...

7 years ago | 2 answers | 0

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Question

Interpolate uniform to non-uniform sampling, artifacts with spline
Hi, I have to resample uniformly sampled data to a non-uniform sampling. I use the spline function for this, and if the sample...

7 years ago | 0 answers | 0

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Question

Merge multiple GPS and IMU to get more accurate position and attitude
I have multiple GPS and IMU that are located at known positions of an aircraft. Is there a ready to use implementation to merge...

7 years ago | 0 answers | 0

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Question

Best way to smooth GPS data
Hi, I have a GPS signal sampled at 1Hz. It is too noisy, so I want to smooth the signal. I tried using a moving average, but i...

7 years ago | 3 answers | 0

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Question

reshape, remove 16 elements, keep 1000*8, remove ..
Can I solve this without a loop?/What is the fastest way? I have a long vector consisting of [16Elements 1000*8Elements 16Eleme...

7 years ago | 1 answer | 0

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Question

Calculate only fraction of spectrum with FFT
I have a signal with 4096 samples. I can calculate the frequency spectrum of this signal with fft. But I am only interested in...

7 years ago | 1 answer | 0

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Question

I need your help! I am going to read a lot of big files with fread. Any ideas on how to speed this up? Also if there is a way ...

7 years ago | 2 answers | 0

### 2

Question

Matrix indexing: fast way to compute covariance of N different MxL matrices that are saved in NxMxL matrix
I have a NxMxL matrix called bigmatrix That I can split into N temporary submatrices. On each temporary submatrix I need to ca...

7 years ago | 1 answer | 0

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Question

IFFT calculate only one timesample
I have a frequency signal and I apply an IFFT to it. This results in the time domain x(n) which has N samples. But I am really...

7 years ago | 1 answer | 0

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Question

Combine multiplication filter in time and frequency domain
Hello, I perform a FFT on my signal x, which yields X. Then I perform a multiplication in the frequency with my filter W, whic...

7 years ago | 1 answer | 0

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Question

bsxfun to multiply matrix with vector multiple times in for loop --> how faster?
I have a 2D matrix of size NxN, and each row I am multiplying with a 1xN vector with bsxfun in a for loop like this: for k=...

7 years ago | 2 answers | 0

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Question

How to vectorize loop with linspace for performance
Besides prelocation my matrix A, how can I save time here? for k=1:1:10000 A(k,:)=firstValue(k):fixedStep:lastValue(k); ...

8 years ago | 1 answer | 0

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Question

Fast Look-up table
Good morning, I have a long array signal with values x. Now for each of those values x I want to find the closest fit in anoth...

9 years ago | 1 answer | 0

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Question

Highly interpolate complex spectrum
Good afternoon, I have a complex spectrum of a signal that is centered around a center frequency with a certain bandwidth. I...

9 years ago | 0 answers | 0

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Question

Highly oversample FFT2 in one direction for peak detection
Hello, I have a 2D image and the resulting FFT2 has high peak. Now I can find the maximum to get the resulting peak shift in e...

9 years ago | 0 answers | 0

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Question

Translate position uncertainty of two objects to uncertainty of distance between them
Hello, I have a plane and in this plane there are two objects. The real location of each object is somewhere in the circle o...

9 years ago | 0 answers | 0

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Question

Probability of two adjacent cells being below gaussian percentile
Hello, I have a matrix, whose data is described by a gaussian curve. Now I have a probability of 8%, that the data falls below...

10 years ago | 1 answer | 0

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Question

Precision when dividing two functions going against zero
Hi, I have two functions A=sinc(c1*x)-cos(c2*x) whichs is Zero for x=0. Now I want to calculate A/(c3*x). The expected result...

10 years ago | 2 answers | 0

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Question

Hello, with imgradient I can compute the magnitude and direction of an image's gradient. Is it also possible to somehow comput...

10 years ago | 1 answer | 0

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Question

Height difference between earth models
Hello, is it possible to calculate the height difference between earth models at specific points of lat and long? For example ...

10 years ago | 0 answers | 0