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Unable to do calculations involving variables in Ocean

Anik1989

Hi all,

 

Sorry if this question has been answered before but my search didn't reveal anything.  I am having trouble with the following lines in my script:

 

------------------------------------------------- 

 ocnWaveformTool( 'wavescan )

simulator( 'spectre )

design("/home/a5islam/simulation/complete_circuit/spectre/schematic/netlist/netlist")

resultsDir("/home/a5islam/simulation/complete_circuit/spectre/schematic")

modelFile('("/CMC/kits/cmosp35.4.3/models/B3V/mm0355v.scs" "tt"))

;frequency of the sine wave input [Hz]

freq = 2

printf("Frequency: %L\n", freq)

tduration = 1*(1/freq)

printf("Duration: %L\n", tduration)

 -------------------------------------

The output of the file is:

Frequency: 2

Duration: 0

I think that when I calculate tduration using (1/freq), it fails to get the value of "freq". If I replace "freq" with its numeric value 2, then duration is 0.5 as expected.

 

In a related note, Cadence also complains when I try to use the following code:

 tduration=1e-3 

 analysis('tran ?start "0" ?stop tduration)

But if I replace tduration with its numeric value, the analysis runs fine.  

Is there some special way to access the values of variables in Ocean that I'm not aware of?  

Two things I should mention:

(i) If I declare all my variables as design variables and use VAR(""), there are no problems whatsoever. However, this seems like an excessive and tedious solution. 

(ii) I am saving my script as an .ocn file and then typing Load("FileName.ocn") in the CIW to run the script. Not sure if this has any bearing on the current situation.

 

Any advice is appreciated!

 

Anik 

 

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  • skillUser

    Hi Anik,

    The problem appears to be that you are performing integer division in your code, hence 1/2 yields 0.  You can force your hand by doing something like 1.0/freq - this should solve your problem here.

    I have not looked into your second issue, but I see that the start is "0" and the tduration is just 1e-3, so perhaps you could try a string for the second argument, e.g. sprintf(nil "%g" tduration) ?

    Hope this helps!

    Lawrence.

Reply
  • skillUser

    Hi Anik,

    The problem appears to be that you are performing integer division in your code, hence 1/2 yields 0.  You can force your hand by doing something like 1.0/freq - this should solve your problem here.

    I have not looked into your second issue, but I see that the start is "0" and the tduration is just 1e-3, so perhaps you could try a string for the second argument, e.g. sprintf(nil "%g" tduration) ?

    Hope this helps!

    Lawrence.

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