LAE

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Originally posted by: dhrobertson

Hi,

I having a problem with a Do While loop. I'm just trying to test the logic so the graph itself may not make much sense but, the issue is, the loop will go round once, and increment the "counter", in this case lineno. it continues and with the loop and outputs as expected, but the 3rd time it goes around where the lineno is now 2.... the node "Determine Next" will not evaluate the lineno as expected and assigns the final value.

in other words:

I have an if statement which increases lineno. it works successfully for 2 passes after which is doesn't evaluate when lineno == "2" and jumps to the final assignment of "5".

what might be happening here? I cant work it out... is something happening in the Do While node which is causing lineno to stop evaluating or am I doing something stupid?

nodes are pasted below... any help appreciated...

thanks

Douglas


node:Static_Data_3
bretype:core::Static Data
editor:sortkey=56bdf60f489f3ca6_2
output:@40fe6c55598828e5/=
prop:StaticData=<<EOX
country_code:string,line:string
CA,this is CA1
CA,this is CA2
CA,this is CA3
CA,this is CA4
CA,this is CA5
CA,this is CA6
CA,this is CA7
CA,this is CA8
CA,this is CA9
CA,this is CA9
PT, this is PT1
PT, this is PT2
PT, this is PT3
PT, this is PT4
PT, this is PT5
PT, this is PT6
SE, this is SE1
SE, this is SE2
SE, this is SE3
SE, this is SE4
EOX
editor:XY=1140,660
end:Static_Data_3

node:XRef_5
bretype:core::X-Ref
editor:sortkey=56bdf5d2237f661e_4
input:@45781ca80c2802d0/=Static_Data_3.40fe6c55598828e5
input:@45781ca971fe502f/=States_4.40fe6c55598828e5
output:@45781cad02e051b0/=
output:@457826825d7c2de0/=
output:@4578268450ad5d88/=
prop:LeftInputKey=<<EOX
country_code
EOX
prop:RightInputKey=<<EOX
State
EOX
prop:SortLeftInput=true
prop:SortRightInput=true
editor:XY=1310,660
node:Sort_2
bretype:::Sort
editor:shadow=45782670131b71e8
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort_2

node:Bypass_3
bretype:::Bypass
editor:shadow=4578267017753cec
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass_3

node:Join
bretype:::Join
editor:shadow=457826701862249e
input:@40fd2c745b6d7704/=
input:@40fd2c74504921cd/=
output:@40fd2c7430f76546/=
output:@457826cc03a465f4/=
output:@457826cc510c69e0/=
end:Join

node:Bypass
bretype:::Bypass
editor:shadow=4578267041681261
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass

node:Sort
bretype:::Sort
editor:shadow=4578267075a60d09
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort

end:XRef_5

node:States_4
bretype:core::Static Data
editor:Label=States
editor:sortkey=56bdf60f1dd53337_3
output:@40fe6c55598828e5/=
prop:StaticData=<<EOX
lineno:unicode,State
1,CA
EOX
editor:XY=1140,750
end:States_4

node:XRef_2
bretype:core::X-Ref
editor:sortkey=56bdf5d2237f661e_3
input:@45781ca80c2802d0/=Static_Data_3.40fe6c55598828e5
input:@45781ca971fe502f/=XRef_6.457826825d7c2de0
editor:bend=1=1750|850
editor:bend=1=1750|930
editor:bend=1=1260|930
output:@45781cad02e051b0/=
output:@457826825d7c2de0/=
output:@4578268450ad5d88/=
prop:LeftInputKey=<<EOX
country_code
EOX
prop:RightInputKey=<<EOX
State
EOX
prop:SortLeftInput=true
prop:SortRightInput=true
editor:XY=1290,790
node:Sort_2
bretype:::Sort
editor:shadow=45782670131b71e8
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort_2

node:Bypass_3
bretype:::Bypass
editor:shadow=4578267017753cec
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass_3

node:Join
bretype:::Join
editor:shadow=457826701862249e
input:@40fd2c745b6d7704/=
input:@40fd2c74504921cd/=
output:@40fd2c7430f76546/=
output:@457826cc03a465f4/=
output:@457826cc510c69e0/=
end:Join

node:Bypass
bretype:::Bypass
editor:shadow=4578267041681261
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass

node:Sort
bretype:::Sort
editor:shadow=4578267075a60d09
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort

end:XRef_2

node:Do_While_4
bretype:core::Do While
editor:sortkey=56d0287458cc4346
input:@537256b86cbc760c/=XRef_5.457826825d7c2de0
input:@537256ba68710f32/=XRef_2.457826825d7c2de0
output:@537256d866506f43/=
output:@537389af52916f5d/=
prop:WhileScript=<<EOX
emit *
setSuccessReturnCode(101)
EOX
editor:XY=1430,660
node:Bypass
bretype:::Bypass
editor:shadow=5418a18062c250fe
input:@5373907f34d02b95/=
input:@537390b90a07215c/=
output:@40fd2c7436717256/=
end:Bypass

node:Output_BRD_File
bretype:::Output BRD File
editor:shadow=5418a18079a32a59
input:@40fd2c7476600190/=
end:Output_BRD_File

node:BRD_File
bretype:::BRD File
editor:shadow=5418a1804a3b7eb6
output:@40fd2c742cab0bf0/=
end:BRD_File

node:Filter_2
bretype:::Filter
editor:shadow=5418a180664f1c14
input:@40fd2c74167f1ca2/=
output:@40fd2c7420761db6/=
end:Filter_2

node:Static_Data
bretype:::Static Data
editor:shadow=5418a1800209138c
output:@40fe6c55598828e5/=
end:Static_Data

node:Switch
bretype:::Switch
editor:shadow=5418a180494e0bdd
input:@51645e775c5b5fb1/=
input:@51645e7c5d73480d/=
inputattr:@51645e7c5d73480d.type=optional
output:@51645e802b0d6e53/=
end:Switch

node:Agg
bretype:::Agg
editor:shadow=5418a18070a07535
input:@40fd2c7427456e5b/=
output:@40fd2c744c862db0/=
end:Agg

node:Filter
bretype:::Filter
editor:shadow=5420671f12257e11
input:@40fd2c74167f1ca2/=
output:@40fd2c7420761db6/=
end:Filter

end:Do_While_4

node:Determine_next_loop_3
bretype:core::Filter
editor:Label=Determine next loop
editor:sortkey=56bdf60f1ac70cc5_2
input:@40fd2c74167f1ca2/=Do_While_4.537389af52916f5d
output:@40fd2c7420761db6/=
inclock:/=Append_Excel
prop:Script=<<EOX

if lineno == "1" then {lineno = "2"}
else
if lineno == "2" then {lineno = "3"}
else
lineno = "5"

override emit lineno.unicode() as lineno

where firstExec
EOX
editor:XY=1530,780
end:Determine_next_loop_3

node:States_5
bretype:core::Static Data
editor:Label=States
editor:sortkey=56bdf60f1dd53337_4
output:@40fe6c55598828e5/=
prop:StaticData=<<EOX
lineNo:unicode,State
2,PT
3,SE
EOX
editor:XY=1530,860
end:States_5

node:Append_Excel
bretype:core::Append Excel
editor:sortkey=56d029a163d25952
input:@49e34a5e55c82040/=Do_While_4.537389af52916f5d
prop:DataAppendMethod=Append
prop:ExistingDataPreservation=Preserve All
prop:File=c:\looptext.xls
editor:XY=1660,670
end:Append_Excel

node:XRef_6
bretype:core::X-Ref
editor:sortkey=56bdfa280eb42d29_2
input:@45781ca80c2802d0/=Determine_next_loop_3.40fd2c7420761db6
input:@45781ca971fe502f/=States_5.40fe6c55598828e5
output:@45781cad02e051b0/=
output:@457826825d7c2de0/=
output:@4578268450ad5d88/=
prop:LeftInputKey=<<EOX
lineno
EOX
prop:RightInputKey=<<EOX
lineNo
EOX
prop:SortLeftInput=true
prop:SortRightInput=true
editor:XY=1680,850
node:Sort_2
bretype:::Sort
editor:shadow=45782670131b71e8
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort_2

node:Bypass_3
bretype:::Bypass
editor:shadow=4578267017753cec
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass_3

node:Join
bretype:::Join
editor:shadow=457826701862249e
input:@40fd2c745b6d7704/=
input:@40fd2c74504921cd/=
output:@40fd2c7430f76546/=
output:@457826cc03a465f4/=
output:@457826cc510c69e0/=
end:Join

node:Bypass
bretype:::Bypass
editor:shadow=4578267041681261
input:@45782010749f0c96/=
input:@457820124fef7658/=
output:@40fd2c7436717256/=
end:Bypass

node:Sort
bretype:::Sort
editor:shadow=4578267075a60d09
input:@40fd2c743ebf4304/=
output:@40fd2c746a2a3b47/=
end:Sort

end:XRef_6

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Originally posted by: simon.wilby

Hi,

have you reviewed the IterationExample.brg shipped with LAE? this example covers various different ways that the looping functionality can be used.

You should find the IterationExample.brg in your Public documents/ Lavastorm BRAIN/Examples folder.

Hope that helps

Simon

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Originally posted by: ryeh

The problem is in the 'Determine Next Loop' filter. You set the variable 'lineno' to the next value. But that's the same name as the field. So just creating a temp variable '_lineno' and then emitting that as 'lineno' fixes the problem.
Attachments:
loopExample.brg

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Originally posted by: dhrobertson

Originally posted by: ryeh
					

The problem is in the 'Determine Next Loop' filter.  You set the variable 'lineno' to the next value.  But that's the same name as the field.  So just creating a temp variable '_lineno' and then emitting that as 'lineno' fixes the problem.
			

Knew I was being stupid... just couldn't see it! thank you!

doug

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Originally posted by: dhrobertson

Originally posted by: ryeh
					

The problem is in the 'Determine Next Loop' filter.  You set the variable 'lineno' to the next value.  But that's the same name as the field.  So just creating a temp variable '_lineno' and then emitting that as 'lineno' fixes the problem.
			

out of interest, I notice that you use the function CONSUME... I tried to understand the help file with regards this command but struggled to understand it.... can you let me know what it does exactly? I'm assuming it is forfilling the role of the firstexec command? but how is it working exactly?

thanks

Doug

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Originally posted by: ryeh

So in your case, it doesn't matter that much, since you only have 10 records coming in, and each iteration happens really quick. But say you had 1M records coming in, and the logic in the filter takes 1 second (I'm being dramatic here). Then what would happen is that you would actually have to wait 1M seconds for the filter to run even though you only care about the first record. Use CONSUME to basically discards all the remainder of the records. So after you process the first record, you throw away the remainder of the input and move on. Check out the example that my colleague, Josh Belliveau, created to illustrate the difference.
Attachments:
ConsumeFunction.brg

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Originally posted by: dhrobertson

ah I see. thank you for the explanation !

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Originally posted by: stonysmith

I want to add one point of clarity.. CONSUME causes the node to stop processing the input. It doesn't "skip over" the records, it stops reading of any more input records.

Imagine this:
In this case, all input records (potentially millions) are read - taking a lot of CPU time, I/O processing, etc. even though the output is only 99 records.

But..
will cause the node to read the first 99 records and then stop processing, potentially saving you significant amounts of time.

It can also be written this way for brevity.
As soon as C is greater than 99, it will stop.

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Originally posted by: samsons

hen what would happen is that you would actually have to wait 1M seconds for the filter to run even though