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Problem in reading from a file

Question asked by VIRALPARIKH on Oct 9, 2006
Latest reply on Oct 11, 2006 by mfredrik

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I would like to read input stimuli for my RF block from the external file.

Here is the brief description of my design.

I have 5 raws in my "in.dscr" external file with 2 variables in each raw. I have "Transient Simulator" running from 0ns to 10ns. I also have DAC and
PramSweep components to sweep index of the input file. ParamSweep is linked with my Transient Simulator.

Here is the problem.

At the end of the simulation, I see that each raw is read and simulation is performed for 10ns based on its variable values. (As my simulation time is 10 ns in transient simulator). So, I get 5 curves, one for each raw, running from 0 to 10 ns. This is not what I need. I want to fire values of each raw's variables sequencially. Means, simulation should show only 1 curve from 0 to 10 ns and each 2
ns span should be based on one raw's values. What should I do ?

Please let me know if you need any more information to understand the problem.

Thanks,
Viral

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mfredrik Oct 10, 2006 3:16 AM

You want the values to change vs the simulatuion time if I understand you correctly. A "Discrete" file type is probably not the best choice for that. If you use a generic MDIF file then you can have the time value as your lookup column and correspodning data for one or more parameters. Here's an example Generic MDIF file:

BEGIN MYDATA
% time(real) R1(real) C1(real)
0 1 1E-12
1E-9 1 1E-12
2E-9 2 3E-12
3E-9 2 3E-12
4E-9 3 4E-12
5E-9 3 4E-12
6E-9 4 6E-12
7E-9 4 6E-12
8E-9 5 9E-12
9E-9 5 9E-12
10E-9 5 9E-12
END

The DataAccess component would be setup like this in the schematic window:

DAC1
File="[FileName]"
Type=Generalized Multi-dimensional Data (Generic MDIF)
InterpMode=Linear
InterpDom=Rectangular
ExtrapMode=InterpMode
iVar1="time"
iVal1=time

Then you can use the value of R1 and C1 from the file in components, like:

R=file{DAC1,"R1"} Ohm
C=file{DAC1,"C1"} F

When you simulate this, the time value is passed to the DAC and the corresponding row is looked up based on the current simulation time. The value of R1 and C1 will change vs tim.

-Mats

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VIRALPARIKH Oct 10, 2006 7:20 AM

Hello Mats,

This precisely what I wanted. I tried and its working. Thanks a lot.

Could you please help me for one more thing ? I am trying to dump node voltages and currents in an external file. So, I can use them in Matlab for post-processing.

I tried to use "write_var" in "Measurement_Expresson". Though, I am saving only one variable, it's giving me error; "Only one-dimentional data can be saved into file". According to me, my variable is one-dimentional only.

What should I use ? Is there any better way of doing it ?

-- Viral

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mfredrik Oct 10, 2006 7:42 AM

If you use a Parameter Sweep ontop of the Transient Simulation then the results are not one-dimensional. The voltage(s) are now a two-dimensional array, vs the swept parameter (and time) in the ParamSweep.

Try to disable the Parameter Sweep and verify that it works without the extra Parameter Sweep.

As a workaround for write_var not supporting multi-dimensional data...you can export the dataset using the Data File/IO tool as a Generic MDIF file.

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VIRALPARIKH Oct 11, 2006 7:35 AM

Hi Mats,

Thanks for your reply. I tried and it's working. However, when I created file from the dataset, it contains all the variables and at arbitary resolution.

Is there any better way to save few specific variables at every clock edge ?

Thanks,
Viral

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mfredrik Oct 11, 2006 2:44 PM

You can export a listing column in the Data Display to an ascii file. You can postprocess your data, and list the variable(s) in a listing column in the Data Display and then export it to an ascii file.

See the manual for more info:
Export List to file

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5 Replies

mfredrik Oct 10, 2006 3:16 AM
Mark Correct
Correct Answer
You want the values to change vs the simulatuion time if I understand you correctly. A "Discrete" file type is probably not the best choice for that. If you use a generic MDIF file then you can have the time value as your lookup column and correspodning data for one or more parameters. Here's an example Generic MDIF file:

BEGIN MYDATA
% time(real) R1(real) C1(real)
0 1 1E-12
1E-9 1 1E-12
2E-9 2 3E-12
3E-9 2 3E-12
4E-9 3 4E-12
5E-9 3 4E-12
6E-9 4 6E-12
7E-9 4 6E-12
8E-9 5 9E-12
9E-9 5 9E-12
10E-9 5 9E-12
END

The DataAccess component would be setup like this in the schematic window:

DAC1
File="[FileName]"
Type=Generalized Multi-dimensional Data (Generic MDIF)
InterpMode=Linear
InterpDom=Rectangular
ExtrapMode=InterpMode
iVar1="time"
iVal1=time

Then you can use the value of R1 and C1 from the file in components, like:

R=file{DAC1,"R1"} Ohm
C=file{DAC1,"C1"} F

When you simulate this, the time value is passed to the DAC and the corresponding row is looked up based on the current simulation time. The value of R1 and C1 will change vs tim.

-Mats
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VIRALPARIKH Oct 10, 2006 7:20 AM
Mark Correct
Correct Answer
Hello Mats,

This precisely what I wanted. I tried and its working. Thanks a lot.

Could you please help me for one more thing ? I am trying to dump node voltages and currents in an external file. So, I can use them in Matlab for post-processing.

I tried to use "write_var" in "Measurement_Expresson". Though, I am saving only one variable, it's giving me error; "Only one-dimentional data can be saved into file". According to me, my variable is one-dimentional only.

What should I use ? Is there any better way of doing it ?

-- Viral
Like • Show 0 Likes0
Actions
mfredrik Oct 10, 2006 7:42 AM
Mark Correct
Correct Answer
If you use a Parameter Sweep ontop of the Transient Simulation then the results are not one-dimensional. The voltage(s) are now a two-dimensional array, vs the swept parameter (and time) in the ParamSweep.

Try to disable the Parameter Sweep and verify that it works without the extra Parameter Sweep.

As a workaround for write_var not supporting multi-dimensional data...you can export the dataset using the Data File/IO tool as a Generic MDIF file.
Like • Show 0 Likes0
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VIRALPARIKH Oct 11, 2006 7:35 AM
Mark Correct
Correct Answer
Hi Mats,

Thanks for your reply. I tried and it's working. However, when I created file from the dataset, it contains all the variables and at arbitary resolution.

Is there any better way to save few specific variables at every clock edge ?

Thanks,
Viral
Like • Show 0 Likes0
Actions
mfredrik Oct 11, 2006 2:44 PM
Mark Correct
Correct Answer
You can export a listing column in the Data Display to an ascii file. You can postprocess your data, and list the variable(s) in a listing column in the Data Display and then export it to an ascii file.

See the manual for more info:
Export List to file
Like • Show 0 Likes0
Actions

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