nl_tokens: Solve Ax = b where A is upper triangular
pl_tokens: function trsv ( A , x , isLower ) { var dot = blas1 . dot ; var n = A . shape [ 1 ] ; var i = 0 ; if ( isLower ) { x . set ( 0 , x . get ( 0 ) / A . get ( 0 , 0 ) ) ; for ( i = 1 ; i < n ; i ++ ) { x . set ( i , ( x . get ( i ) - dot ( A . pick ( i , null ) . hi ( i ) , x . hi ( i ) ) ) / A . get ( i , i ) ) ; } } else { x . set ( n - 1 , x . get ( n - 1 ) / A . get ( n - 1 , n - 1 ) ) ; for ( i = n - 2 ; i >= 0 ; i -- ) { x . set ( i , ( x . get ( i ) - dot ( A . pick ( i , null ) . lo ( i + 1 ) , x . lo ( i + 1 ) ) ) / A . get ( i , i ) ) ; } } return <mask> ; }