Possibly more people know about Mata now than about Stata's old matrix
language, so I'll point out that elementwise division of matrices is
possible in Stata using -matewd- from STB-50:
STB-50 dm69 . . . . . . . . . . . . . . . . . . Further new matrix
commands
(help matdelrc, matewm, matmad, matpow if installed) . . . N.
J. Cox
7/99 pp.5--9; STB Reprints Vol 9, pp.29--34
collection of new matrix commands providing additional matrix
checking, management, element-wise operators, maximum absolute
difference, and power
See also
STB-39 dm49 . . . . . . . . . . . . . . . . . . . . Some new matrix
commands
(help matfunc, varfunc if installed) . . . . . . . . . . . J.
Weesie
9/97 pp.17--20; STB Reprints Vol 7, pp.43--48
collection of new matrix commands; several for explicit matrices
and a few for implicit matrices (i.e., variables)
STB-56 dm79 . . . . . . . . . . . . . . . . . . Yet more new matrix
commands
(help matcorr, matewmf, matvsort, svmat2 if installed) . . N.
J. Cox
7/00 pp.4--8; STB Reprints Vol 10, pp.17--23
commands to produce a correlation matrix, elementwise monadic
function of another matrix, selected subsets of matrix rows
and columns, vec or vech of a matrix, elements sorted within
a vector, matrix from a vector, and commands to save matrices
I've unlimited respect for Mata, but it is not obvious to me that it is
a better language for quite what you are doing than Stata itself -- and
I don't mean Stata's matrix language either. Presumably your rows and
columns have identities that have meaning to you. Looking at 400 X 400
matrices of such a kind is not easy in Mata.
If you represent your matrices by variables,
Row identifier
Col identifier
Cell values for matrix 1
Cell values for matrix 2
...
Then elementwise division is naturally just division and most other
basic analyses will be equally trivial.
Nick
[email protected]
Victor, Jennifer Nicoll
Thanks to Nick for recommending a running sum of matrices for my problem
yesterday. I worked like a dream. Now I have a new problem.
I have created two matrices in Stata using the matrix commands. One is
called "rawsum," a 438x1010 matrix. The other is "bothvoting," also a
438x1010 matrix.
I need to create matrix agreecount=(rawsum+bothvoting)/2. No problem.
Now I need to create matrix agreerate=agreecount/bothvoting, where each
i,j of 'agreecount' is divided by each i,j of 'bothvoting'. I cannot
find a command in Stata's matrix commands to do this type of
element-wise division.
So, I've moved into Mata. Mata has a simple element-wise division
command: X=A:/B.
But, I am a novice Mata-user and I cannot figure out how to get my
438x438 matrix into Mata. So, I've converted it back to a dataset using
the 'svmat' command and I'm trying to get the data into Mata using the
'st_view' command. My data has 438 observations and 438 variables.
Essentially, I want to use the command:
st_view(x., ., "agreecount1",..."agreecount438")
...then do the same with the 'bothvoting' data, then execute the e-w
division command.
I've tried using the 'for' command but cannot figure out the successful
execution of a loop in Mata because the syntax is different than
Stata's.
How can I do this? Or can you provide a more elegant solution?
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