SizeGetSeqIndex Method (Int64, Int64)

public long GetSeqIndex(
	long d0,
	long d1
)

Public Function GetSeqIndex ( 
	d0 As Long,
	d1 As Long
) As Long

Dim instance As Size
Dim d0 As Long
Dim d1 As Long
Dim returnValue As Long

returnValue = instance.GetSeqIndex(d0, 
	d1)

Parameters

d0

Type: SystemInt64
Index into the first dimension.

d1

Type: SystemInt64
Index into the second dimension.

Return Value

For arrays of matrix shape d0 references the index of the row and d1 references the index of the column of the sequential index to return.

More general, for n-dimensional arrays the first index corresponds to the position in the first (index: 0) dimension and the second index to the position of the element in the second dimension (index: 1).

If the array refered to by this size stores more dimensions than addressed by this function the last index parameter d1 can exceed the limits of its corresponding dimension. In this case the sequential index to be returned is computed by subsequently merging trailing dimensions and applying the superflous modulos of the value of d1 to the next dimension, correspondingly. This process is repeated until either the number of dimensions is reached or the modified new value of d1 reaches 0.

Any index parameter may be negative, in which case the resulting index is computed by adding the corresponding dimension length to the parameters value. Hence, a value of -1 addresses the last element in the dimension. Note, that for the last specified dimension a value of -1 references the last element in the _virtual_ dimension, merged with any non specified trailing dimensions.

This function recognizes arbitrary strides. It expects all sizes (dimension lengths, strides, the base offset and the number of elements) to fit into MaxValue. Consider using one of the overloads with UInt32 parameters if you are not dealing with very big arrays and don't require negative indexing. This may bring better performance in tight loops.

Performance hint: this function (and all corresponding overloads) are optimized for the case where the number of index parameters provided corresponds to the number of dimensions in the array and all provided index parameters are within the range of their corresponding dimension. The functions, however, handle arbitrary cases, including addressing, merging and ommitting trailing dimensions. Any of those extended features may introduce a performance penalty, though.

[ILNumerics Core Module]

Reference