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From |
"Sergiy Radyakin" <serjradyakin@gmail.com> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
st: Function el() fails |

Date |
Fri, 15 Aug 2008 17:54:44 -0400 |

Dear All, after investigating why my program sometimes breaks, I have found a problem (observed in Stata 9 and Stata 10 for Windows) with the function el(matrixname, row, col ), which could be reproduces with the following sequence of commands: // ----- BEGIN ------- sysuse auto matrix p=1 matrix a=p matrix dir matrix list a di a[1,1] di el(a,1,1) matrix list p di p[1,1] di el(p,1,1) // ----- END ------- According to the help file for Stata 9: el(A,i,j) the i,j element of A (same as A[i,j]) Note that the program above works for matrix name "a" and not "p". This made it difficult to identify the problem. Because the problem is observed for some datasets and not for others. It seems that the namespace of variables and matrix names in Stata is overlapping. I've met the messages earlier regarding what namespaces are shared, but I can't find them at the moment. The manual explicitly defines the term "namespace" in the [P] matrix, (page 235 in 10th edition). It also mentions that there is a single namespace for scalars and matrices, however it does mention variables in a rather confusing statement: "Scalars and matrices share the same namespace; i.e., scalars and matrices may have the same names as variables in the dataset, etc., but they cannot have the same names as each other." Confusion here is that indeed Stata allows me to have a matrix with the same name as a variable, but I'd really like the built-in commands and functions to be able to WORK with that matrix. (Function el() as all functions in Stata is built-in). I wonder if anyone could elaborate on which namespaces are shared in Stata, in particular: variables locals globals scalars matrices programs classes all sort of mata objects all sort of graphics related styles, patterns, etc .... [not sure how long the list is, but the above list is definitely not complete] I am not sure that the problem above is an intended behavior. In any case it makes the case that el(a,1,1) is NOT equivalent to A[1,1] against what the help file says. If this is not an intended behaviour, can this be fixed? Thank you, Sergiy Radyakin CC: Stata Technical Support * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: Function el() fails***From:*"Scott Merryman" <scott.merryman@gmail.com>

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