When you say you "would like to get the first row of first matrix with first row of 2nd matrix cncatanated", does that make two rows in you final array or one?
E.g.
row 0 of array 1 = 1 2 3
row 0 of array 2 = 21 22 23
What do you want in the final array?
Case1:
row 0 = 1 2 3 21 22 23
or
Case 2:
row 0 = 1 2 3
row 1 = 21 22 23
For either case, use Index Array (or auto-index in a For loop) on array 1 and array 2 to get one row at a time, then use Build Array to put the rows together.
For Case 1, use Build Array with Concatenate Inputs selected (right-click on Build Array and select Concatenate Inputs). Then use a single element Build Array to make one row a 2D array.
For Case 2, use Build Ar
ray with Concatenate Inputs not selected.
See the attached LabView 6.1 example.