>square-matrix ( m -- subset )

Vocabulary

math.matrices

Inputs

m

a matrix

Outputs

subset

a square-matrix

Word description

Find only the square subset of the input matrix.

Examples

USING: math.matrices prettyprint ; { { 0 2 4 6 } { 1 3 5 7 } } >square-matrix .
{ { 0 2 } { 1 3 } }

Definition

USING: combinators kernel math sequences ;

IN: math.matrices

:: >square-matrix ( m -- subset )
    m dimension first2 :> ( x y ) {
        { [ x y = ] [ m ] }
        { [ x y < ] [ x <iota> m cols transpose ] }
        { [ x y > ] [ y <iota> m rows ] }
    } cond ;