The way Intel IPP for small matrices operates on vector arrays is similar to its operation on single vectors. Thus, different vectors cannot be combined into one array, unless the following conditions are fulfilled:
vectors have equal length
vectors have identical structure, i.e. if superposed by memory shift, they will coincide.
See Figure “Combining Vectors into an Array”, cases A, B, C for proper vector sets. If one or both of these conditions is not satisfied, vectors cannot be combined into an array (see Figure “Combining Vectors into an Array”, cases D, E).
However, not all proper vectors can be combined into an array. Another important condition is vector layout.
The vector layout is called regular, if the vectors are equally spaced in memory; otherwise, the layout is called irregular. In these terms, vectors can be combined in the following way (see Figure “Permissible Vector Arrays”, cases A, B, C):
regular vectors with regular layout
regular vectors with irregular layout
irregular vectors with regular layout
Irregular vectors with irregular layout cannot be combined into an array (see Figure “Permissible Vector Arrays”, case D).
