#
INDEX

Indexing Multidimensional Arrays

**INDEX**,
a C library 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.

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2D Array Example:

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

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Licensing:

The computer code and data files described and made available on this
web page are distributed under
the GNU LGPL license.

###
Languages:

**INDEX** is available in
a C version and
a C++ version and
a FORTRAN90 version and
a MATLAB version.

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Related Data and Programs:

CELL,
a C library 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.

index_test

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Source Code:

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Last revised on 09 July 2019.
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