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Support Answers MathWorks. Search MathWorks. MathWorks Answers Support. Open Mobile Search. Trial software. You are now following this question You will see updates in your activity feed. You may receive emails, depending on your notification preferences. Cumulative sum with conditions. Vote 0. Edited: Bruno Luong on 4 Oct Accepted Answer: Bruno Luong. I am counting a number of 1's in an array.

But I want to count the cumulative sums only when the number of 1's are followed by a sequence of zeros. I want to count the cumulative sums S of those arrays as follows.

I would truly appreciate if any one could advise me an effective way of programming the conditional sums. Rik on 3 Oct Documentation Help Center. If A is a vector, then cumsum A returns a vector containing the cumulative sum of the elements of A.

If A is a matrix, then cumsum A returns a matrix containing the cumulative sums for each column of A. If A is a multidimensional array, then cumsum A acts along the first nonsingleton dimension. For example, if A is a matrix, then cumsum A,2 returns the cumulative sum of each row. You must specify Aand optionally can specify dim. For instance, cumsum A,2,'reverse' returns the cumulative sum within the rows of A by working from end to beginning of the second dimension.

Find the cumulative sum of the integers from 1 to 5. Find the cumulative sum of the columns of A. Find the cumulative sum of the rows of A. Calculate the cumulative sum along the rows. Specify the 'reverse' option to work from right to left in each row.

The result is the same size as A. Create a vector containing NaN values and compute the cumulative sums. By default, cumsum includes NaN values. You can ignore NaN values in the cumulative sum calculation using the 'omitnan' option. Data Types: double single int8 int16 int32 int64 uint8 uint16 uint32 uint64 logical duration Complex Number Support: Yes. Dimension to operate along, specified as a positive integer scalar.

If no value is specified, then the default is the first array dimension whose size does not equal 1. Direction of cumulation, specified as 'forward' default or 'reverse'. The sum of elements containing NaN values is the sum of all non- NaN elements. If all elements are NaNthen cumsum returns 0. Cumulative sum array, returned as a vector, matrix, or multidimensional array of the same size as the input array A. The class of B is the same as the class of A except if A is logicalin which case B is double.

The first nonsingleton dimension is the first dimension of an array whose size is not equal to 1. If X is a 1-by-n row vector, then the second dimension is the first nonsingleton dimension of X. If X is a 1-byby-n empty array, then the second dimension is the first nonsingleton dimension of X. If X is a 1-byby-3 array, then the third dimension is the first nonsingleton dimension of X. This option allows quick directional calculations without needing a flip or reflection of the input array.

Logical inputs are not supported. Cast input to double first. Code generation does not support sparse matrix inputs for this function. The order of the additions within the cumsum operation is not defined. Therefore, the cumsum operation on a gpuArray might not return exactly the same answer as the cumsum operation on the corresponding MATLAB numeric array. The differences might be significant when A is a signed integer type. Therefore, the cumsum operation on a distributed array might not return exactly the same answer as the cumsum operation on the corresponding MATLAB numeric array.Documentation Help Center.

The Cumulative Sum block computes the cumulative sum along the specified dimension of the input or across time running sum. Input, specified as a vector or as matrix inputs containing real or complex values. This port is unnamed until you select a non- None value for the Reset port parameter. Data Types: single double int8 int16 int32 int64 uint8 uint16 uint32 uint64 fixed point Complex Number Support: Yes. The rate of the input to the Rst port must be the same or slower than that of the input data signal.

The sample time of the input to the Rst port must be a positive integer multiple of the input sample time. Data Types: single double int8 int16 int32 int64 uint8 uint16 uint32 uint64 Boolean. Data Types: single double int8 int16 int32 int64 uint8 uint16 uint32 uint64 fixed point. Specify the dimension along which to compute the cumulative summations. You can choose to sum along Channels running sumColumnsor Rows. For more information, see these sections:.

Summing Along Columns. Summing Along Rows. Specify how the block processes the input when computing the running sum along the channels of the input.

You can set this parameter to one of these options:. Columns as channels frame based — The block treats each column of the input as a separate channel. Elements as channels sample based — The block treats each element of the input as a separate channel.

This parameter is available only when you set the Sum input along parameter to Channels running sum. Determines the reset event that causes the block to reset the sum along channels. For more information, see Resetting the Running Sum. Floating-point inheritance takes precedence over the data type settings defined on this pane.

When inputs are floating point, the block ignores these settings.Sign in to comment. Sign in to answer this question. Unable to complete the action because of changes made to the page.

## Cumulative sum of cell array column

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You may receive emails, depending on your notification preferences. How to calculate a cumulative sum in a loop? Sandy Stone on 20 Nov Vote 0. Commented: Walter Roberson on 21 Nov Accepted Answer: Walter Roberson. I have a loop that looks like this:. I've tried cumsum, but it doesn't work. Any ideas are appreciated. Azzi Abdelmalek on 20 Nov Cancel Copy to Clipboard.

There is no cumulative sum in your code, can you explain what you want? Accepted Answer. Walter Roberson on 21 Nov Vote 1. Before the loop. Sandy Stone on 21 Nov Thank you!By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

The logic is that if a vector is created for s using x, why would not the sum function behave the same way? The above returns just the first element 2 for all x.

The issue is that 1:x is 1 and that sum reduces linear arrays. To do this properly, you need a 2d array and then sum the rows:. You are asking two questions, really. One is - how do I compute the cumulative sum. SouldEc's answer already shows how the cumsum function does that. Your other question is.

But in fact the arguments on either side of the colon operator must be scalars - they cannot be vectors themselves. I'm surprised that you say Matlab isn't throwing an error with your two lines of code - I would have expected that it would I just tested this on Freemat, and it complained Here, we could use arrayfun.

It evaluates a function with an array as input element-by-element; this can be useful for a situation like this. So if we write.

This will loop over all values of x, substitute them into the function sum A 1:nand voila - your problem is solved. Learn more. Asked 6 years, 6 months ago. Active 6 years, 6 months ago. Viewed 4k times. I am trying to resolve why the following Matlab syntax does not work.

Active Oldest Votes. Soul Ec Soul Ec 6 6 silver badges 11 11 bronze badges. Thanks very much for both solutions. But really - the right answer is "use cumsum " Floris Floris Many thanks. The key hole in my knowledge was that the arguments on either side of the colon must be scalar.

I should have known that! I am using Matlab a and it didn't complain, which is possible the reason I did not ping to the problem. Yes, I actually implemented it using the for loop, but I asked the question because I had an intuitive feeling that there was probably a better way. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Featured on Meta.Documentation Help Center.

If A is a vector, then cumsum A returns a vector containing the cumulative sum of the elements of A.

If A is a matrix, then cumsum A returns a matrix containing the cumulative sums of each column of A. For example, if A is a matrix, then cumsum A,2 returns the cumulative sum of each row. For instance, cumsum A,2,'reverse' returns the cumulative sum within the rows of A by working from end to beginning of the second dimension.

Create matrix a 4-by-4 symbolic matrix A all elements of which equal 1. Compute the cumulative sum of elements of A. By default, cumsum returns the cumulative sum of each column. Calculate the cumulative sum along the columns in both directions. Specify the 'reverse' option to work from right to left in each row.

Calculate the cumulative sum along the rows in both directions. Direction of cumulation, specified as the 'forward' default or 'reverse'.

Cumulative sum array, returned as a vector or matrix of the same size as the input A. Choose a web site to get translated content where available and see local events and offers.

Based on your location, we recommend that you select:. Select the China site in Chinese or English for best site performance. Other MathWorks country sites are not optimized for visits from your location. Toggle Main Navigation. Buscar en Soporte Soporte MathWorks.

Search MathWorks. Off-Canvas Navigation Menu Toggle. Trials Trials Actualizaciones de productos Actualizaciones de productos. Cumulative Sum of Vector Create a vector and find the cumulative sum of its elements. Reverse Cumulative Sum Create matrix a 4-by-4 symbolic matrix, all elements of which equal 1.

### Cumulative sum with conditions

Input Arguments collapse all A — Input array symbolic vector symbolic matrix. Input array, specified as a vector or matrix. Dimension to operate along, specified as a positive integer.

The default value is 1. Consider a two-dimensional input array, A : cumsum A,1 works on successive elements in the columns of A and returns the cumulative sum of each column.

Output Arguments collapse all B — Cumulative sum array vector matrix. See Also cumprod fold int symprod symsum.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here.

Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I want to calculate a cumulative sum of the values in column 2 of dat. The desired output is shown as dat2. Not completely vectorized solution it loops through the segments of sequential 1sbut should be faster.

It's doing only 2 loops for your data. Learn more. Ask Question. Asked 9 years, 10 months ago. Active 9 years, 9 months ago. Viewed 5k times. Jessy Jessy Active Oldest Votes. I wonder if the function DIFF only applicable to test one condition? If I want to find cumulative sum which fullfill two conditions, how to do that without using the function FIND?

Jonas: I remember this from your answer to another question. Don't have IPT here to test. Anyway, my code is pretty simple. The challenge is how to do cumsum for all groups without for-loop. I will be happy to see an example using bwlabel, since I face with similar problem all the time.

Ashish Uthama.

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