Applying function to all cells in a matrix using it as a reference
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Good day to everyone,
I've run into a problem which is best described using the following example. Given Matrix A which is defined as
% code
A=[.9 .8 .7
.6 .5 .4];
I need to transform all cells within the aforementioned Matrix A according to the following formula (Fisher's Z transformation)
where a is each cell in Matrix A. I want to create a matrix B where this is the result of this computation. The resulting matrix B would be
if true
% code
B=[1.47 1.09 0.86
0.69 0.54 0.42]
end
Here is the calculation which yielded the last data entry in matrix B
采纳的回答
Image Analyst
2014-12-5
Yes, and so what heppened when you typed that exactly into MATLAB like this:
format short g;
A=[.9 .8 .7
.6 .5 .4];
Z = 0.5 * log((1+A) ./ (1-A))
Did you see something that you did not expect? Or you didn't know ln was done by the log() function? Or you didn't know how to use ./ or parentheses? It's only one line of code virtually identical to your formula, so where are you having trouble?
3 个评论
Image Analyst
2014-12-5
P.S. Let's not call "elements" "cells" because "cells" are a certain type of variable that is well described here.
Andrew Lapointe
2014-12-5
编辑：Andrew Lapointe
2014-12-5
Image Analyst
2014-12-5
That does an "element-by-element" divide, rather than a matrix divide. Same as with .* and * - you know what a matrix multiply is, right? And that's different than if you must multiply a(1,1) by b(1,1) and a(2,1) by b(2,1). Matrix multiple multiplies a row by a column and then sums. It's very different.
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