sub process {
    my( $AoA,  $thingToProcess ) = @_;
    my( $v1, $v2, $v3, $v4, $v5, $v6, $v7 ) = @{ $AoA->[ $thingToProcess ] };
    
    my( $r1, $r2, $r3, $r4, $r5, $r6, $r7 ) = ( ... some calculation(s) involving $v1, $v2, $v3, $v4, $v5, $v6, $v7 ... );

    @{ $AoA->[ $thingToProcess ] } = ( $r1, $r2, $r3, $r4, $r5, $r6, $r7 );
    return;
}

##</code><code>##

sub process {
    my( $AoA,  $thingToProcess ) = @_;

    $AoA->[ $thingToProcess ][ 3 ] =  $AoA->[ $thingToProcess ][ 1 ] * $AoA->[ $thingToProcess ][ 2 ];
    ...
    return;
}