/ sparse matrix multiply (matrix table dict) tf:{select x:y,y:x,z from x} tt:{select z$v by x,y from(+`x`a`v!.+x;+`a`y`z!.+y)} /select x.z$y.z by x.x,y.y from x,y where x.y=y.x /select x.z$y.z by x.x,y.y from (x;y)on x.y=y.x tm:{+`x`y`z!(&#:'i;,/i;,/x@'i:(&~0=)'x)} mt:{./[(1+|/'x)#0**v;+x@:`x`y;v:(x:+x)`z]} u:tf t:tm m:(2 0;1 3;0 1) u:tf t:+`x`y`z!("iif";",")0:"a1.csv" \t tt[t;u] dt:{. exec y!z by x from x} td:{+`x`y`z!+,/(!#x),''{(!x),'. x}'x} df:{dt tf td x} e:df d:dt t \t d$e