{smcl} {* 04aug2020}{...} {cmd:help mata mm_prod()} {hline} {title:Title} {p 4 10 2} {bf:mm_prod() -- compute product of elements in a matrix} {title:Syntax} {p 8 23 2} {it:real scalar}{bind: } {cmd:mm_prod(}{it:real matrix Z}{cmd:)} {p 8 23 2} {it:real colvector}{bind: } {cmd:mm_rowprod(}{it:real matrix Z}{cmd:)} {p 8 23 2} {it:real rowvector}{bind: } {cmd:mm_colprod(}{it:real matrix Z}{cmd:)} {title:Description} {pstd} {cmd:mm_prod()} returns the product of the elements in matrix {it:Z}. Stata 10 or newer is required. {pstd} {cmd:mm_rowprod()} returns a column vector containing the product of elements within each row of {it:Z}. {pstd} {cmd:mm_colprod()} returns a row vector containing the product of elements within each column of {it:Z}. {title:Examples} {com}: Z = (1, 2, -5, -8) \ (3, 3, 1, -4) {res} {com}: Z {res} {txt} 1 2 3 4 {c TLC}{hline 21}{c TRC} 1 {c |} {res} 1 2 -5 -8{txt} {c |} 2 {c |} {res} 3 3 1 -4{txt} {c |} {c BLC}{hline 21}{c BRC} {com}: mm_prod(Z) {res} -2880 {com}: mm_rowprod(Z) {res} {txt} 1 {c TLC}{hline 7}{c TRC} 1 {c |} {res} 80{txt} {c |} 2 {c |} {res}-36{txt} {c |} {c BLC}{hline 7}{c BRC} {com}: mm_colprod(Z) {res} {txt} 1 2 3 4 {c TLC}{hline 21}{c TRC} 1 {c |} {res} 3 6 -5 32{txt} {c |} {c BLC}{hline 21}{c BRC}{txt} {title:Conformability} {cmd:mm_prod(}{it:X}{cmd:)} {it:X}: {it:r x c} {it:result}: 1 {it:x} 1 {cmd:mm_rowprod(}{it:X}{cmd:)} {it:X}: {it:r x c} {it:result}: {it:r x} 1 {cmd:mm_colprod(}{it:X}{cmd:)} {it:X}: {it:r x c} {it:result}: 1 {it:x c} {title:Diagnostics} {pstd}The functions return missing if {it:Z} is void. {pstd}Missing values in {it:Z} turn the product to missing. {title:Source code} {pstd} {help moremata10_source##mm_prod:mm_prod.mata} {title:Author} {pstd} Ben Jann, University of Bern, ben.jann@soz.unibe.ch {title:Also see} {psee} Online: help for {helpb mf_sum:sum()}, {helpb moremata} {p_end}