st: How to save a series of vector from a double loop in mata

[Preeya Mohan <preeyamohan100@hotmail.com>]

Dear Statalisters,
 
I am having a problem saving a series of vectors from a double loop using mata. I am working with Stata 12.1 for Windows.
 
I calculate distance between two locations using the haversine formula from a double loop in mata. Let's call the two locations location A and B. I create two matrices A and B each containing the latitude and longitude coordinates. For each A location, I calculate out the distance to each B location, that is, if each A and B matrix contain 4 rows each in the end I should get 16 distances calculated as shown below. Each time the loop runs however 4 column vectors are created containing only 4 distances each and I can only save the last vector. I would however like to store each vector into one large matrix with all 16 distances.

Thank you for your time in reading this.
 
A     B     distance
1     1 
1     2
1     3
1     4
2     1
2     2
2     3
2     4
3     1
3     2
3     3
3     4
4     1
4     2
4     3
4     4


Yours,
Preeya 		 	   		  
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