Compile question

*To*: mathgroup at smc.vnet.net*Subject*: [mg73825] Compile question*From*: "Ray Koopman" <koopman at sfu.ca>*Date*: Thu, 1 Mar 2007 06:18:52 -0500 (EST)

I've been trying different ways to "walk the list" as suggested in the recent thread "split again". Here is some uncompiled code that works as I expected, but the compiled version returns reals instead of integers. Does anyone know why? SeedRandom[2]; z = Table[Random[],{20}] {0.238705,0.844529,0.473928,0.421515,0.512692, 0.0228035,0.529257,0.0507012,0.74907,0.632356, 0.0725195,0.251276,0.902785,0.672727,0.419794, 0.512577,0.404555,0.00984124,0.168643,0.50482} s4[z_,a_,b_] := Module[{n = Length@z, j = 0, k}, k = n; Do[If[ z[[i]] >= a, If[ i <= j+b+1, j = i, k = i-1; Break[]]], {i,n}]; If[ k <= j+b, {}, {j+1,k} ] ] s4[z,.7,5] s4[z,.7,6] s4[z,.7,7] {3,8} {14,20} {} s4c = Compile[{{z,_Real,1},{a,_Real},{b,_Integer}}, Module[{n = Length@z, j = 0, k}, k = n; Do[If[ z[[i]] >= a, If[ i <= j+b+1, j = i, k = i-1; Break[]]], {i,n}]; If[ k <= j+b, {}, {j+1,k} ] ], {{n,_Integer},{j,_Integer},{k,_Integer},{i,_Integer}} ]; s4c[z,.7,5] s4c[z,.7,6] s4c[z,.7,7} {3.,8.} {14.,20.} {}