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From |
Sebastian Eppner <eppner@uni-potsdam.de> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: MATA all combinations / pairs of a row |

Date |
Sat, 8 Oct 2011 00:28:50 +0200 |

Hi, yes, based on the select and rowsum = 2 logic I wrote this (unfortunately it has to use one loop... first I thought that may be ok... in reality in really is time consuming... if there are ANY ideas out there how to prevent the loop, i' be very grateful). BASIC = ( 1,1,1) \ (1,1,0) \ (1,0,1) \ (0,1,1) \ (0,0,1) \ (0,1,0) \ (1,0,0) PROPERTIES = (0,9,10) \ (0.45, 0.2, 0.35) PROP1 = PROPERTIES[1,.] PROP1 = diag(PROP1) PROP1 = BASIC * PROP1 PROP2 = PROPERTIES[2,.] PROP2 = diag(PROP2) PROP2 = BASIC * PROP2 Now I have 3 Matrices with all the information i needed. The problem was now: > For each row/combination in BASIC I need to find all PAIRS of Ones > that are contained in the combination. For any pair, I need to > multiply: > PROP1 of Element1 * PROP1 of Element2 * abs(PROP2 of Element1-PROP2 > of ELEMENT2) I calculated the latter not only for pairs, but for all rows (later i only use the pair rows) PAIRS = rowmax(PROP1):*rowmin(PROP1):*(rowmax(PROP2)-rowmin(PROP2)) Then I calculate the sum of all pairs contained in the first row. see the select() which only selects those rows that are: - contain only elements that are also elements in row one of BASICS (that i do by subtracting all rows from the first one, and then I look if there is a -1 somewhere) - contain only pairs (as Nick suggested that means the rowsum is 2) mata: result = colsum(select(PAIRS, (rowmin(BASIC[1,.]:-BASIC):>-1):& rowsum(BASIC):==2)) of course i need the result for all the other rows too! thats where i cant think of anything but a loop (****jsdf) forvalues i=2/`lastrow' { mata: result = result \ colsum(select(PAIRS, (rowmin(BASIC[`i',.]:-BASIC):>-1):& rowsum(BASIC):==2)) } any suggestion would be magic. Thanks, Sebastian On Thu, Oct 6, 2011 at 2:16 AM, Nick Cox <njcoxstata@gmail.com> wrote: > One idea only from me. Look at -select()- and think of rowsums being 2. > > Nick > > On Wed, Oct 5, 2011 at 10:08 PM, Sebastian Eppner <eppner@uni-potsdam.de> wrote: >> Hi, >> I have N elements. In this example N will be 3. But in my application >> it will be usually around 7, going up to 20 in some cases… >> >> Each element can be either 1 or 0. My basic matrix has all 2^N, here >> 2^3 permutations of the elements: >> >> BASIC = ( 1,1,1) \ (1,1,0) \ (1,0,1) \ (0,1,1) \ (0,0,1) \ (0,1,0) \ >> (1,0,0) \(0,0,0) >> >> The elements have 2 “properties” , PROP1 and PROP2 each, stored in 2 >> rows of another matrix, for example: >> >> PROPERTIES = (1.4,4.6,8.1) \ (0.2, 0.4, 0.4) >> >> Every row in BASIC resembles a unique combination of the elements. >> What I want to do, is to calculate some indicators for every >> combination, using the Properties of the elements. >> >> An easy example would be to calculate the total sum of PROP1 for each >> combination. I just need to multiply the “diagonalized” first row of >> the PROPERTIES Matrix with the BASIC Matrix and then calculate the >> rowsum of this resulting matrix. >> >> >> What I want to do now is more complex and I am really stuck. The >> indicator I want to calculate now is the following: >> >> For each row/combination in BASIC I need to find all PAIRS of Ones >> that are contained in the combination. For any pair, I need to >> multiply: >> >> PROP1 of Element1 * PROP1 of Element2 * abs(PROP2 of Element1-PROP2 >> of ELEMENT2) >> >> It is the sum of all PAIRS that I need to know for every row…. >> >> >> Of course, not every row has PAIRS in it… all rows with only 1 One >> have no pairs, so the result for these rows should be 0 (or missing, I >> don’t care). >> >> Also, many rows (those with only 2 Ones) have only a single Pair… >> >> In my Example with 3 elements, only the first row sums up more than >> one (3) Pair(s)…. >> >> >> I am looking for a way to solve this problem by not using loops… and >> as much matrix algorithms as possible. Since I have a lot of BASIC >> Matrices with more elements than 3… I guess the whole thing would be >> very very time consuming if I started smth with loops… Maybe there is >> no way to get rid of any loop… any idea would be very welcome (even >> some, with a little looping). > > * > * 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/ > -- Sebastian Eppner Lehrstuhl für Vergleichende Politikwissenschaft Wirtschafts- und Sozialwissenschaftliche Fakultät Universität Potsdam August-Bebel-Straße 89 14482 Potsdam Telefon: +49-331-977-3305 eppner@uni-potsdam.de * * 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: MATA all combinations / pairs of a row***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: MATA all combinations / pairs of a row***From:*Sebastian Eppner <eppner@uni-potsdam.de>

**Re: st: MATA all combinations / pairs of a row***From:*Nick Cox <njcoxstata@gmail.com>

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