st: Mata in an rclass program to bootstrap

["Nelson, Carl" <chnelson@illinois.edu>]

I tried to embed mata code in an r class program to bootstrap. The program starts

capture program drop welfareboot
program define welfareboot, rclass
version 10

it executes nlsur to estimate a parametric model

then 

mata:

ndm = st_matrix("ndm")
pdm = st_matrix("pdm")
npar = st_matrix("nonpoor")
ppar = st_matrix("poor")
.
.
.
end 

when I try to return scalars calculated by the mata program I get

return scalar cvnb = cvnbord
non r-class program may not set r()
r(151);

Is there a proper way to embed mata in a program to bootstrap that will not create this error?

Carl Nelson

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