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How do I calculate yearly average value for large data set with uneven time spacing?
If your 2-column matrix is A, try: years = floor(A(:,1)); data = A(:,2); means = accumarray(years, data) ./ accumarra...

9 years 前 | 1

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Is there a simple way to reference months from data in matlab time?
Using the attached function, you can do this: [isplit, ~, meantime] = splitTimes(tm, 'month'); % get start and end point of...

9 years 前 | 1

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assigning to object variables from within-object functions
MATLAB always makes a copy when you assign an object, or pass an object to a function. Here's another example of the same thing,...

9 years 前 | 0

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Why do get error in line 10: Function Keyword is invalid here. This might cause later messages about end.
You can't mix a script and a function in the same m-file. If an m-file contains a function, the first line of code in the file m...

9 years 前 | 2

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how to evaluate a convolution integral by fast fourier transform
Correct zero-padding to use the FFT for 1-D or 2-D convolutions is implemented in my FEX submission <http://uk.mathworks.com/mat...

9 years 前 | 0

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Is there a way to direct an algorithm in edge detection, or correct my drawing outline of the edge?
This is exactly what active contours, or snakes, were originally designed for. If you have the Image Processing Toolbox, have a ...

9 years 前 | 0

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Delete a column from an array of uncertain size?
The trick needed is to use the fact that cell arrays can be expanded into comma-separated lists, so can represent any number of ...

9 years 前 | 1

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how can i save pixel changes in image?
Could be because JPEG compression loses information, so a write followed by a read only returns an approximation to the original...

9 years 前 | 0

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How to arrange stacked Images into a 2 dimension array?
Images2d = reshape( ... permute( ... reshape(Images, 1000, 1000, 8, 5), ... ...

9 years 前 | 0

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Can you use MATLAB for 3D Image Processing?
It may be useful to look at the <http://uk.mathworks.com/products/computer-vision/index.html Computer Vision System Toolbox>, wh...

9 years 前 | 1

提问

parfor warning and analysis of switch statement
I have two functions which are, I think, functionally identical. Both use a |parfor| loop. If the logic within the loop is expre...

9 years 前 | 1 个回答 | 1

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the rang of unit 8 is 0-255 But im2double convert the range to [0, 1] instead of [0, 255]. please anyone explain it????
It's very helpful to have a standard range of values for images. The convention used in MATLAB toolbox functions is that images ...

9 years 前 | 3

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what are the units of the houghlines 'FilleGap' and 'MinLength' ?
Yes, they are in pixels.

9 years 前 | 0

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[DEPRECATED] What frustrates you about MATLAB?
The |inputParser / validateattributes / validatestring| collection of function parsing and checking tools. * You have to writ...

9 years 前 | 5

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Using knnsearch to find nearest values ignoring NaN's
You need to organise the nearest neighbour search so that it uses both latitude and longitude together, not search each separate...

9 years 前 | 0

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Undefined function 'mtimes' for input arguments of type 'audiorecorder'.
Presumably you replaced data = wavrecord( ... ); by data = audiorecorder( ... ); (I don't know what arguments we...

9 years 前 | 0

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Matrix dimension reduction based on summation
If you try to reduce an 81 x 81 matrix to a 10 x 10 matrix it is bound to be messy, because 81 is not a multiple of 10. You have...

9 years 前 | 1

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Multiplying structures together based on field names
A function to multiply two structures field by field. This needs to be copied into a file on your MATLAB path called multiplyStr...

9 years 前 | 0

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How to change a range of pixel values in a Grayscale JPEG image?
Like this (where A is the array containing the image): A(A >= 60 & A <= 95) = 255; By the way, that the image is stored ...

9 years 前 | 0

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已回答
Splitting an array and working on individual sections.
If you want to put the four smaller arrays into separate variables, you can do it like this (assuming the sizes are even as stat...

9 years 前 | 0

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Improve efficiency of array multiplication
The value of SW is not used in the code you've shown. If you don't need the value of SW, it will help to omit this line. If you ...

9 years 前 | 0

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subtraction ele by ele
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9 years 前 | 0

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What is an edge exacty in matlab? is it simply a line ?
I assume you're referring to David Legland's <http://www.mathworks.com/matlabcentral/fileexchange/7844-geom2d toolbox> from the ...

9 years 前 | 0

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已回答
How can use a for loop to name a matrix?
One way is to use a cell array, like this for trials = 1:max_trials < compute result, assign to a > output_matri...

9 years 前 | 0

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Using fileparts and combining with a different file name
The last line should be filenc = [fName '.nc']; What you are doing here is concatenating two strings. Square brackets ca...

9 years 前 | 1

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What causes an "Argument to dynamic structure reference must evaluate to a valid field name" error please? code attached.
The dot after |sin| makes it look like a structure rather than a function call. Omit the dot.

9 years 前 | 1

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Filling in array with specific numbers
One way, using |repmat| to make the repeated values: % test data A = [1;2;3]; B = [11;12;13;14]; C = [21;22;23]; ...

9 years 前 | 4

已回答
Vectorizing a loop that calculates cosd on every element?
You don't need vectorization to avoid computing the cosine on every iteration through the lambda loop - just put the calculation...

9 years 前 | 0

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已回答
what is the difference between imshow(im) or imshow(im, [])
If the second argument is not a spatial referencing object, a colormap or a string, it specifies the display range. From the <ht...

9 years 前 | 1

已回答
I need help arranging two vectors
[AreaSorted, idx] = sort(Area); LengthSorted = Length(idx); WidthSorted = Width(idx);

9 years 前 | 2