The method will define a subarray starting at Index and ending at Index+Len-1. No copying will occur, only pointers will be shifted or indices adjusted. The routine allows for stack based pushing and poping of sub-ranges with the additional constraint that each deepening of the sub-range is strictly within the bounds of the previous one. The pairs of SetSubRangeLevel/SetFullRangeLevel need to match. 

All values of the original TMtxVecBase will be preserved. An exception will be raised, if an attempt is made to change the size of calling object. 

It is possible to call SetSubRange/SetFullRange on the object, which has been subranged with SetSubRangeLevel. 

To again obtain a view of the previous subrange level on the vector/matrix, call SetFullRangeLevel 

The Index parameter of the SetSubRange is absolute for the original memory or current stack level. The Index parameter for the SetSubRangeLevel is relative to the previous SetSubRangeLevel call.

SetSubRangeLevel Method