anti-transpose ( matrix -- newmatrix )
Matrix operations

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Vocabulary
math.matrices

Inputs

matrix

a matrix

Outputs

newmatrix

a matrix

Word description
Like transpose except that the matrix is transposed over the anti-diagonal, so that the anti-diagonal itself is preserved and the main-diagonal is reversed.

Notes
This word is the opposite variant of transpose.

Examples

USING: math.matrices sequences prettyprint ; 5 <iota> <diagonal-matrix> anti-transpose .
{ { 4 0 0 0 0 } { 0 3 0 0 0 } { 0 0 2 0 0 } { 0 0 0 1 0 } { 0 0 0 0 0 } }

Definition

USING: kernel math.matrices.private sequences ;

IN: math.matrices

: anti-transpose ( matrix -- newmatrix )
    dup empty?
    [ ] [
        [
            dup regular-matrix?
            [ matrix-cols-iota ] [ unshaped-cols-iota ] if
        ] keep dup array-matrix?
        [ array-anti-transpose-unsafe ]
        [ generic-anti-transpose-unsafe ] if
    ] if ;