Carl Nelson <[email protected]> reports, 
> The following stata syntax produced the error that b was not found at the
> gen command, even though it was listed by mat l
> mata
>    fh = fopen("demcoeff.mat", "r")
>    X = fgetmatrix(fh)
>    fclose(fh)
>    st_matrix("b", X)
> end
> mat l b
> egen lnp1m = median(lnp1)
> egen lnp2m = median(lnp2)
> egen lnp3m = median(lnp3)
> egen lnp4m = median(lnp4)
> egen lnp5m = median(lnp5)
> egen z1m = median(z1)
> egen z2m = median(z2)
> egen lnexpm = median(lnexp)
> 
> gen ap =  $A_NOT + b[1,1]*lnp1m + b[1,2]*lnp2m + b[1,3]*lnp3m + b[1,4]*lnp4m + (1-b[1,1]-b[1,2]-b[1,3]-b[1,4])*lnp5m 
I suspect that the error message Carl got was not "b not found" but "+b not
found".  If I'm right, that happened because global macro A_NOT was 
note defined and thus the last line appeared to Stata as 
> gen ap =  + b[1,1]*lnp1m + b[1,2]*lnp2m + b[1,3]*lnp3m + b[1,4]*lnp4m + (1-b[1,1]-b[1,2]-b[1,3]-b[1,4])*lnp5m 
Am I right?
-- Bill
[email protected]
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