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edited Apr 13, 2017 at 12:56

The fastest I could come up with, using the undocumented Compile`GetElement for indexing (it's the fastest even without):

f = Compile[ {{l, _Integer, 1}}, Module[ {max = -1}, Do[ If[max < Compile`GetElement[l, i], max = Compile`GetElement[l, i]], {i, 1, Length@l}]; max > 0 ], CompilationTarget -> "C" ]

Using timeAvg from Mr.Wizard's answer answer,

MemberQ[a, _?Positive] // timeAvg Total@UnitStep[-a] =!= Length@a // timeAvg Positive@Max@a // timeAvg f[a] // timeAvg (* 1.38034 0.114101 0.0187749 0.00830531 *)

The fastest I could come up with, using the undocumented Compile`GetElement for indexing (it's the fastest even without):

f = Compile[ {{l, _Integer, 1}}, Module[ {max = -1}, Do[ If[max < Compile`GetElement[l, i], max = Compile`GetElement[l, i]], {i, 1, Length@l}]; max > 0 ], CompilationTarget -> "C" ]

Using timeAvg from Mr.Wizard's answer,

MemberQ[a, _?Positive] // timeAvg Total@UnitStep[-a] =!= Length@a // timeAvg Positive@Max@a // timeAvg f[a] // timeAvg (* 1.38034 0.114101 0.0187749 0.00830531 *)

The fastest I could come up with, using the undocumented Compile`GetElement for indexing (it's the fastest even without):

f = Compile[ {{l, _Integer, 1}}, Module[ {max = -1}, Do[ If[max < Compile`GetElement[l, i], max = Compile`GetElement[l, i]], {i, 1, Length@l}]; max > 0 ], CompilationTarget -> "C" ]

Using timeAvg from Mr.Wizard's answer,

MemberQ[a, _?Positive] // timeAvg Total@UnitStep[-a] =!= Length@a // timeAvg Positive@Max@a // timeAvg f[a] // timeAvg (* 1.38034 0.114101 0.0187749 0.00830531 *)

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answered Jul 30, 2012 at 18:00

acl

The fastest I could come up with, using the undocumented Compile`GetElement for indexing (it's the fastest even without):

f = Compile[ {{l, _Integer, 1}}, Module[ {max = -1}, Do[ If[max < Compile`GetElement[l, i], max = Compile`GetElement[l, i]], {i, 1, Length@l}]; max > 0 ], CompilationTarget -> "C" ]

Using timeAvg from Mr.Wizard's answer,

MemberQ[a, _?Positive] // timeAvg Total@UnitStep[-a] =!= Length@a // timeAvg Positive@Max@a // timeAvg f[a] // timeAvg (* 1.38034 0.114101 0.0187749 0.00830531 *)