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Re: st: RE: Create graph directly from matrix?

From   Nick Winter <>
Subject   Re: st: RE: Create graph directly from matrix?
Date   Mon, 16 Nov 2009 12:59:10 -0500

yes indeed. It is a nifty application of the existing principle that had not occurred to me!

Nick Cox wrote:
I agree. This is clever. But there is no new principle here. _n in any expression yielding a new variable is interpreted observation by observation. Nick
Nick Winter

Ah, interesting.

Looking within -_matplot-, it looks like the fundamental answer to my question might be "no", since that program creates temporary variables that it then plots.

But it uses an interesting construction that may help me go the variables route without using -svmat-:

gen x = Xy[_n,1] in 1/16

creates a new variable -x- from the first column of matrix Xy. Pretty spiffy to use _n to tag the observation number/row number.

- Nick

Nick Cox wrote:
Check out the undocumented command -_matplot-. Nick
Nick Winter

I'm wondering if there is a way to convert the values held into a
into a graph (ie, into a serset that serves as the basis for a graph) directly, without first making the matrix into variables?

Why I'm curious:

I'm thinking about revising my -oprobpr- command, which plots
probabilities after order l/probit models. The new -margins- command can fairly easily calculate what's required for the plotting, and
results can be saved as a matrix, using -margins-'s -post- option.

So I'd like to plot the estimates returned in e(b) against values in

I can put this stuff all together in one matrix, eg:

sysuse auto
probit foreign mpg price weight

margins, atmeans at(mpg=(12(2.9)41)) post
mat b = e(b)
mat X = e(at)
mat Xy = X , b'

Then I'd like to create, eg, a line plot of the final column (named
against the first column (mpg).

I can, of course, use -svmat-, graph the relevant variables, and drop the variables.

But I'd love a more elegant solution.

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Assistant Professor                             434.924.3359 f
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