index, a C code which can convert the index of a multidimensional array entry into the corresponding index of a one dimensional vector, using either row or column major indexing, with zero or unit base.
Consider, for example, the following 3x4 array A:
11 12 13 14
21 22 23 24
31 32 33 34
Indexing by columns, the array would be stored in a 1D vector as
11 21 31 | 12 22 32 | 13 23 33 | 14 24 34
and the indexing of the elements would be
11 21 31 | 12 22 32 | 13 23 33 | 14 24 34
0 1 2 3 4 5 6 7 8 9 10 11 <- zero based
1 2 3 4 5 6 7 8 9 10 11 12 <- one based
Indexing by rows, the array would be stored in a 1D vector as
11 12 13 14 | 21 22 23 24 | 31 32 33 34
and the indexing of the elements would be
11 12 13 14 | 21 22 23 24 | 31 32 33 34
0 1 2 3 4 5 6 7 8 9 10 11 <- zero based
1 2 3 4 5 6 7 8 9 10 11 12 <- one based
The computer code and data files described and made available on this web page are distributed under the MIT license
index is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
CELL, a C code which defines a cell array, a generalization of an array which can compactly store and retrieve vector or matrix data of varying size, such as the rows of a triangular matrix.