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From |
"NEYMOTIN, FLORENCE" <[email protected]> |

To |
[email protected] |

Subject |
st: efficiency of coding |

Date |
Sun, 17 Jul 2005 13:50:50 -0700 |

I have two questions for you:

(1) I have a piece of code which I think is probably pretty inefficient and I was wondering whether there is a more efficient alternative. I want to have the log of the median of w conditional on an indicator being set on (denoted as I0, I1, or I2) saved in a scalar variable. I did this by creating a variable denoting the median and then just setting using the first entry of this temporary variable as the scalar and then using that next value to get the log. I think this is probably really roundabout and not taking advantage of stata's capabilities. thanks! Right now, the code looks like:

----------------------------------------------------------------

forvalues i=0(1)2 {

tempvar temp`i'

egen `temp`i''=median(`w') if `I`i''

gsort -`I`i''

*note, the reason this works is because this will always be the first observation after doing the sort, and locals get the first value of variable..TRICKY..

local tempweird=`temp`i''

*THIS IS THE MAIN DEFINITION LINE RIGHT HERE

scalar lw`i'=log(`tempweird')

drop `temp`i''

local drop tempweird

}

----------------------------------------------------------------

(2) If I have two matrices A and B, where A is 15x3, and B is 15x1, and I want to make the third column of A EQUAL to the B matrix, is there a quick way to do this? Right now, I have it replacing value by value in the matrix but I think this is probably slower than it could be.

The code now looks like:

forvalues i=1(1)15{

matrix A[`i' , 3]= B[`i',1]

}

----------------------------------------------------------------

Thanks for your help!

Florence

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**Follow-Ups**:**st: Re: efficiency of coding***From:*"Michael Blasnik" <[email protected]>

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