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interpolating results after a parametric analysis

Ueue

Dear all,

 I have a problem in finding the point (RL_opt) for which an output variable (dg_calc) is equal to a certain value in a parametric analysis.

I did in the following way, but the operation is performed only in the points in which the function is calculated during the parametric analysis. Is it possible to interpolate the data (as automatically done in the waveform viewer -> when you put the mouse in a point you see the value even if it has not been simulated)?

"

; definition of the constants

float NRL = 2

float RLmin = 1M

float RLmax = 100M

float dH = 0.00531

;--------------------------------------------------------------

;--------------------------------------------------------------

analysis('tran ?stop "0.1" ?errpreset "conservative" ?maxstep "10u" )

desVar( "var_load" 25M )

option( 'reltol "1e-6" )

temp( 27 )

paramAnalysis("var_load" ?start RLmin ?stop RLmax ?log NRL)

paramRun()

dg_calc = (...CALCULATIONS...)

RL_opt = xmin(abs(dH - dg_calc) 1)

"

The RL_opt is not very precise, because is not the minimum of the curve (dH-dg_calc) shown in the waveform viewer, but the minimum among the calculated points (in this case it could be different)! Think about a linear function. On the waveform viewer you can extract the value in which it is equal to zero more precisely because there is an interpolation. Is it possible also using an OCEAN script?

 Thanks a lot,

Stefano

Parents

  • Hi Stefano,

    Apologies for the delay in responding - you posted in the wrong forum, and I found this when I was having a quick check through the forums I don't normally follow.

    The ymin or ymax value surely must be at one of the points you've simulated - the minimum or maximum cannot be interpolated - I can't see how this would be any different from what the waveform will do, if you were to plot abs(dH-dg_calc).

    Thinking about it, I think you're comparing with plotting dH-dg_calc, not abs(dH-db_calc), and are just actually trying to find the point at which dg_calc == dH? If so, use the cross() function -  cross(dg_calc dH 1 'either) - I think that's quite likely to be what you want.

    Regards,

    Andrew.

Reply

  • Hi Stefano,

    Apologies for the delay in responding - you posted in the wrong forum, and I found this when I was having a quick check through the forums I don't normally follow.

    The ymin or ymax value surely must be at one of the points you've simulated - the minimum or maximum cannot be interpolated - I can't see how this would be any different from what the waveform will do, if you were to plot abs(dH-dg_calc).

    Thinking about it, I think you're comparing with plotting dH-dg_calc, not abs(dH-db_calc), and are just actually trying to find the point at which dg_calc == dH? If so, use the cross() function -  cross(dg_calc dH 1 'either) - I think that's quite likely to be what you want.

    Regards,

    Andrew.

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