[U] User's Guide

[ U ] 1.3 What’s new 29posts some additional information to e(), and allows evaluators written in Mata as well as ado.See [R] maximize for an overview and see [R] ml and [M-5] moptimize( ).8. Existing command estimates save now has option append, which allows storing more than oneset of estimation results in the same file; see [R] estimates save.9. Existing commands ereturn post and ereturn repost now work with more commands,including logit, mlogit, ologit, oprobit, probit, qreg, qreg, regress, stcox, andtobit. Also, ereturn post and ereturn repost now allow weights to be specified and savethem in e(wtype) and e(wexp). See [P] ereturn.10. Existing command markout has new option sysmissok, which excludes observations with variablesequal to system missing (.) but not to extended missing (.a, .b, . . . , .z); see [P] mark. Thishas to do with new emphasis on imputation of missing values; see [MI] intro.11. New commands varabbrev and unabbrev make it easy to temporarily reset whether Stata allowsvariable-name abbreviations; see [P] varabbrev.12. New programming function smallestdouble() returns the smallest double-precision numbergreater than zero; see [D] functions.13. creturn has new returned values:a. c(noisily) returns 0 when output is being suppressed and 1 otherwise. Thus programmerscan avoid executing code whose only purpose is to display output.b. c(smallestdouble) returns the smallest double-precision value that is greater than 0.c. c(tmpdir) returns the temporary directory being used by Stata.d. c(eqlen) returns the maximum length that Stata allows for equation names.14. Existing extended macro function :dir has new option respectcase, which causes :dir torespect uppercase and lowercase when performing filename matches. This option is relevant onlyfor Windows.15. Stata has new string functions strtoname(), soundex(), and soundex nara(); see [D] functions.16. Stata has 17 new numerical functions: sinh(), cosh(), asinh(), and acosh(); hypergeometric()and hypergeometricp(); nbinomial(), nbinomialp(), and nbinomialtail();invnbinomial() and invnbinomialtail(); poisson(), poissonp(), and poissontail();invpoisson() and invpoissontail(); and binomialp(); see [D] functions.17. Stata has nine new random-variate functions for beta, binomial, chi-squared, gamma, hypergeometric,negative binomial, normal, Poisson, and Student’s t: rbeta(), rbinomial(), rchi2(),rgamma(), rhypergeometric(), rnbinomial(), rnormal(), rpoisson(), and rt(), respectively.Also, old function uniform() is renamed runiform(). All random-variate functions startwith r. See [D] functions.18. Existing function clear has new syntax clear matrix, which clears (drops) all Stata matrices,as distinguished from clear mata, which drops all Mata matrices and functions. See [D] clear.19. These days, commands intended for use by end-users are often being used as subroutines byother end-user commands. Some of these commands preserve the data simply so that, shouldsomething go wrong or the user press Break, the original data can be restored. Sometimes, whensuch commands are used as subroutines, the caller has already preserved the data. Therefore, allprogrammers are requested to include option nopreserve on commands that preserve the datafor no other reason than error recovery, and thus speed execution when commands are used assubroutines. See [P] nopreserve option.