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From |
"Scott Merryman" <scott.merryman@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: need mata or perhaps egen help |

Date |
Thu, 22 May 2008 16:02:26 -0500 |

You can use -st_data()- and -st_store()- to move data between Stata and mata (see -help m4_stata- ) Below is one way: clear //nearest neighbor matrix set obs 20 set seed 12345 forv i = 1/20 { qui gen v`i' = uniform()<.2 in `i'/l qui replace v`i' = 0 in `i' } mata: dist = makesymmetric(st_data(.,.)) mata: dist drop v* //spending set obs 20 gen spending = uniform() gen total =. //total spending of neighbors mata spend = st_data(.,"spending") spend X = dist*spend st_store(.,"total", X) end l Scott On Thu, May 22, 2008 at 3:06 PM, David Merriman <dmerrim@gmail.com> wrote: > I have a set of 584 communities and a square (584x584) matrix D that > measures the > distance from each community to each community. > > For each community I also have (584x1) vector (EDI) containing a > variable that measures (essentially) the total amount spent on > economic development incentives. > > I have this data for a number of years but I do not think that is > important to my programming issues. > > For each of my communities I want a single variable that measures the > total amount spent within a given distance (say 15 miles) on economic > development incentives. > > I can convert my D matrix into a zero/1 matrix > (assign zero to home community and and any community more than 15 > miles distant, 1 otherwise) and Call this DT > > Seems I should be then be able to use mata to do the matrix multiplication > > R=DT*EDI > > R should be a 584x1 vector with the variable I need. > > > The problem (I think) is that I have never used mata and am having a > hard time figuring out how to feed my stata data into mata, do the > multiplication and get the result back to stata. > > Can anyone tell me how to do this? > Maybe there is an easier way to do it with egen or some other stata commands. > > Thanks > Dave Merriman > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: need mata or perhaps egen help***From:*"Sergiy Radyakin" <serjradyakin@gmail.com>

**Re: st: need mata or perhaps egen help***From:*"David Merriman" <dmerrim@gmail.com>

**References**:**st: need mata or perhaps egen help***From:*"David Merriman" <dmerrim@gmail.com>

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