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Subscripts from linear index

`[I,J] = ind2sub(siz,IND)`

[I1,I2,I3,...,In] = ind2sub(siz,IND)

The `ind2sub`

function determines the equivalent subscript values
corresponding to a single index into an array.

`[I,J] = ind2sub(siz,IND)`

returns
the matrices `I`

and `J`

containing
the equivalent row and column subscripts corresponding to each linear
index in the matrix `IND`

for a matrix of size `siz`

. `siz`

is
a vector with `ndim(A)`

elements (in this case, 2),
where `siz(1)`

is the number of rows and `siz(2)`

is
the number of columns.

For matrices, `[I,J] = ind2sub(size(A),find(A>5))`

returns
the same values as `[I,J] = find(A>5)`

.

`[I1,I2,I3,...,In] = ind2sub(siz,IND)`

returns `n`

subscript
arrays `I1`

,`I2`

,`...`

,`In`

containing
the equivalent multidimensional array subscripts equivalent to `IND`

for
an array of size `siz`

. `siz`

is
an `n`

-element vector that specifies the size of
each array dimension.

The `IND`

input can be `single`

, `double`

,
or any integer type. The outputs are always of class `double`

.

The mapping from linear indexes to subscript equivalents for a 3-by-3 matrix is

This code determines the row and column subscripts in a 3-by-3 matrix, of elements with linear indices 3, 4, 5, 6.

IND = [3 4 5 6] s = [3,3]; [I,J] = ind2sub(s,IND) I = 3 1 2 3 J = 1 2 2 2

The mapping from linear indexes to subscript equivalents for a 2-by-2-by-2 array is

This code determines the subscript equivalents in a 2-by-2-by-2
array, of elements whose linear indices 3, 4, 5, 6 are specified in
the `IND`

matrix.

IND = [3 4;5 6]; s = [2,2,2]; [I,J,K] = ind2sub(s,IND) I = 1 2 1 2 J = 2 2 1 1 K = 1 1 2 2

When calling `ind2sub`

for an N-dimensional
matrix, you would typically supply N output arguments in the call:
one for each dimension of the matrix. This example shows what happens
when you return three, two, and one output when calling `ind2sub`

on
a 3-dimensional matrix.

The matrix is 2-by-2-by-2 and the linear indices are 1 through 8:

dims = [2 2 2]; indices = [1 2 3 4 5 6 7 8];

The 3-output call to `ind2sub`

returns the
expected subscripts for the 2-by-2-by-2 matrix:

[rowsub colsub pagsub] = ind2sub(dims, indices) rowsub = 1 2 1 2 1 2 1 2 colsub = 1 1 2 2 1 1 2 2 pagsub = 1 1 1 1 2 2 2 2

If you specify only two outputs (row and column), `ind2sub`

still
returns a subscript for each specified index, but drops the third
dimension from the matrix, returning subscripts for a 2-dimensional,
2-by-4 matrix instead:

[rowsub colsub] = ind2sub(dims, indices) rowsub = 1 2 1 2 1 2 1 2 colsub = 1 1 2 2 3 3 4 4

If you specify one output (row), `ind2sub`

drops
both the second and third dimensions from the matrix, and returns
subscripts for a 1-dimensional, 1-by-8 matrix instead:

[rowsub] = ind2sub(dims, indices) rowsub = 1 2 3 4 5 6 7 8