Hi everyone,
I've searched the resources on Mata for a while and haven't found a solution yet. Here's the issue I'm having: I've created a matrix of 0's (in the example below, it's a matrix with 20 rows and 6 columns) and want to replace the 0's with 1's based on elements of another matrix (called combn_mat in the code below). Eventually, I will write a loop to go through each row of the selecting matrix (combn_mat) and select those column from the first matrix (called pmt in the example) with that index and replace them with 1's.
So, for example:
Thus, in this simple example, I'd like to replace columns 1, 3, 6 in row 7 in matrix pmt with 1's. However, I'm stuck at the point of getting the (1,3,6) into a form that the subset brackets will recognize (i.e., 1,3,6). Thanks in advance for your help! I am using Stata version 14.1.
John
I've searched the resources on Mata for a while and haven't found a solution yet. Here's the issue I'm having: I've created a matrix of 0's (in the example below, it's a matrix with 20 rows and 6 columns) and want to replace the 0's with 1's based on elements of another matrix (called combn_mat in the code below). Eventually, I will write a loop to go through each row of the selecting matrix (combn_mat) and select those column from the first matrix (called pmt in the example) with that index and replace them with 1's.
So, for example:
Code:
. mata:
------------------------------------------------- mata (type end to exit) -----------------------------------------------------------------------------------------------------------------------------------------------------
: x=comb(6,3)
: pmt=J(x,6,0)
: pmt
1 2 3 4 5 6
+-------------------------+
1 | 0 0 0 0 0 0 |
2 | 0 0 0 0 0 0 |
3 | 0 0 0 0 0 0 |
4 | 0 0 0 0 0 0 |
5 | 0 0 0 0 0 0 |
6 | 0 0 0 0 0 0 |
7 | 0 0 0 0 0 0 |
8 | 0 0 0 0 0 0 |
9 | 0 0 0 0 0 0 |
10 | 0 0 0 0 0 0 |
11 | 0 0 0 0 0 0 |
12 | 0 0 0 0 0 0 |
13 | 0 0 0 0 0 0 |
14 | 0 0 0 0 0 0 |
15 | 0 0 0 0 0 0 |
16 | 0 0 0 0 0 0 |
17 | 0 0 0 0 0 0 |
18 | 0 0 0 0 0 0 |
19 | 0 0 0 0 0 0 |
20 | 0 0 0 0 0 0 |
+-------------------------+
: combn_mat=mm_subsets(6,3)'
:
: combn_mat
1 2 3
+-------------+
1 | 1 2 3 |
2 | 1 2 4 |
3 | 1 2 5 |
4 | 1 2 6 |
5 | 1 3 4 |
6 | 1 3 5 |
7 | 1 3 6 |
8 | 1 4 5 |
9 | 1 4 6 |
10 | 1 5 6 |
11 | 2 3 4 |
12 | 2 3 5 |
13 | 2 3 6 |
14 | 2 4 5 |
15 | 2 4 6 |
16 | 2 5 6 |
17 | 3 4 5 |
18 | 3 4 6 |
19 | 3 5 6 |
20 | 4 5 6 |
+-------------+
:
: y=combn_mat[7,]
: y
1 2 3
+-------------+
1 | 1 3 6 |
+-------------+
:
: pmt[7,y]=1
<istmt>: 3301 subscript invalid
(1 line skipped)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
r(3301);
John
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