Extend / replicate a value by column when found in array

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Say I have a matrix 5x5 with binary entries 0 and 1

A=[1 1 1 1 1;1 0 1 1 1;1 0 1 0 0;0 1 1 0 1;1 1 1 0 0]

I'd like to have as a result, a matrix where when the array is parsed by column, if 0 is found, then all rows indexed after are 0:

B=[1 1 1 1 1;1 0 1 1 1;1 0 1 0 0;0 0 1 0 0;0 0 1 0 0]

Any clue for a fast computing solution ? FYI every column is independent.

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KALYAN ACHARJYA 2018-9-6

编辑：KALYAN ACHARJYA 2018-9-6

@cedric The question is not clear for me

cedric W 2018-9-6

That's why I tried to give an example: A is the input matrix, B is the output. Say columns are #of simulations, rows are days. If on a column,on one day the value is 0, then for all the next days it will remain at 0. And you loop for the number so simulations you have. Simulations (columns therefore) are independent. Hope this is clearer.

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Guillaume 2018-9-6

编辑：Guillaume 2018-9-6

在 MATLAB Online 中打开

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This is trivially achieved with cumprod since as soon as a 0 is encountered in a column the cumulative product is 0 from then on:

A = [1 1 1 1 1;1 0 1 1 1;1 0 1 0 0;0 1 1 0 1;1 1 1 0 0]
B = cumprod(A)

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cedric W 2018-9-6

Nice indeed. I was thinking about using cumsum but could find the solution. Thank you !

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