Re: Equation solving from VFP
Thank you Johan but your proposal won't work as it is because (i) the variables Ca, Cb, Va, Ka, Kb and Kw have not been specified (trivial to fix), (ii) VbCalc has not been specified and I am not sure what you intend it to be and (iii) even if I specify a value for VbCalc the line WHILE needs to be DO WHiLE and when it is corrected to DO WHILE generates a Data Type Mismatch error. Clear Ca = 0.1 Cb = 0.1 Vb = 10 Va = 10 Ka = 10^-4.757 ? Ka Kb = 10^-0.2 ? Kb Kw = 1.0E-14 HLow = 0 HHigh=1 H=(HHigh + HLow) / 2 VbCalc = 10 DO WHILE Abs(VbCalc = Vb - Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw/ (H*Kb)) + H - Kw/H)]) > 0.0005 IF VbCalc < Vb HLow=H ELSE HHigh=H ENDIF H=(HHigh + HLow) / 2 ENDDO ? H Paul On 20/12/2022 07:18, Johan Nel wrote: You can do it with binaray intersect. Vb = 10 HLow:= 0 HHigh=1 H=(HHigh + HLow) / 2 WHILE Abs(VbCalc = Vb - Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw⁄ (H*Kb)) + H - Kw/H)]) > 0.0005 IF VbCalc < Vb HLow=H ELSE HHigh=H ENDIF H=(HHigh + HLow) / 2 ENDDO HTH Johan Nel South Africa On 2022/12/14 01:49, Paul Newton wrote: I have the following equation Vb = Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw⁄ (H*Kb)) + H - Kw/H)] Va, Ca, Ka, Cb, Kb and Kw are known or can be provided for any given "run" of the calculation. Typical values might be Va = 10, Ca = 0.1, Ka = 1.8E-5, Cb = 0.1, Kb = 0.63, Kw = 1.0E-14 The aim is to calculate H for various values of Vb and this requires "solving" for H. Various software packages do this in pretty much the same way but the terminology varies: Matlab uses "fsolve", Mathcad uses "find", Maple uses "solve" and Excel uses "GoalSeek". I would like to try to find a way of doing this from VFP. Perhaps there is already a .NET DLL that could be called from VFP? Perhaps with a wrapper to act as a sort of mediator? Failing that, would it be a major task to create something in .NET (perhaps using an existing package)? I really don't know, just thinking aloud ... Paul Newton [excessive quoting removed by server] ___ Post Messages to: ProFox@leafe.com Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: https://leafe.com/archives This message: https://leafe.com/archives/byMID/21c4552c-ace9-3e8a-0571-a22e2e7c9...@gmail.com ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
Re: Equation solving from VFP
You can do it with binaray intersect. Vb = 10 HLow:= 0 HHigh=1 H=(HHigh + HLow) / 2 WHILE Abs(VbCalc = Vb - Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw⁄ (H*Kb)) + H - Kw/H)]) > 0.0005 IF VbCalc < Vb HLow=H ELSE HHigh=H ENDIF H=(HHigh + HLow) / 2 ENDDO HTH Johan Nel South Africa On 2022/12/14 01:49, Paul Newton wrote: I have the following equation Vb = Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw⁄ (H*Kb)) + H - Kw/H)] Va, Ca, Ka, Cb, Kb and Kw are known or can be provided for any given "run" of the calculation. Typical values might be Va = 10, Ca = 0.1, Ka = 1.8E-5, Cb = 0.1, Kb = 0.63, Kw = 1.0E-14 The aim is to calculate H for various values of Vb and this requires "solving" for H. Various software packages do this in pretty much the same way but the terminology varies: Matlab uses "fsolve", Mathcad uses "find", Maple uses "solve" and Excel uses "GoalSeek". I would like to try to find a way of doing this from VFP. Perhaps there is already a .NET DLL that could be called from VFP? Perhaps with a wrapper to act as a sort of mediator? Failing that, would it be a major task to create something in .NET (perhaps using an existing package)? I really don't know, just thinking aloud ... Paul Newton [excessive quoting removed by server] ___ Post Messages to: ProFox@leafe.com Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: https://leafe.com/archives This message: https://leafe.com/archives/byMID/c1922019-990e-4e98-02b5-fa26a5a45...@xsinet.co.za ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
Re: Equation solving from VFP
Thanks Alan
I could certainly do that and I already have a workbook set up but I
would prefer a non-automation method if possible.
Paul
On 14/12/2022 09:10, Alan Bourke wrote:
Thinking aloud, if you could guarantee 32-bit Excel was available you could
probably use Excel automation to do it, i.e.
Create a Workbook programmatically
Fill defined cells with your input values
Do a Goal Seek with result in a defined cell
Read that value back to VFP.
Range("B4").GoalSeek Goal:=-900, ChangingCell:=Range("B3")
___
Post Messages to: ProFox@leafe.com
Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox
OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech
Searchable Archive: https://leafe.com/archives
This message:
https://leafe.com/archives/byMID/83537c76-703a-5beb-e5a8-da614a330...@gmail.com
** All postings, unless explicitly stated otherwise, are the opinions of the
author, and do not constitute legal or medical advice. This statement is added
to the messages for those lawyers who are too stupid to see the obvious.
Re: Equation solving from VFP
> Thinking aloud, if you could guarantee 32-bit Excel was available you could > probably use Excel automation to do it, i.e. Actually, for Office automation it doesn't matter whether it's 32-bit or 64-bit, as long as it is installed on the machine. 32-bit is only relevant for DLLs or drivers. -- Christof ___ Post Messages to: ProFox@leafe.com Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: https://leafe.com/archives This message: https://leafe.com/archives/byMID/31889d12-9d66-4bec-b478-e97e6e7e4...@wollenhaupt.org ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
Re: Equation solving from VFP
Thinking aloud, if you could guarantee 32-bit Excel was available you could
probably use Excel automation to do it, i.e.
Create a Workbook programmatically
Fill defined cells with your input values
Do a Goal Seek with result in a defined cell
Read that value back to VFP.
Range("B4").GoalSeek Goal:=-900, ChangingCell:=Range("B3")
--
Alan Bourke
alanpbourke (at) fastmail (dot) fm
___
Post Messages to: ProFox@leafe.com
Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox
OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech
Searchable Archive: https://leafe.com/archives
This message:
https://leafe.com/archives/byMID/d46dc8ac-2a1f-4b83-852b-4fd327ef8...@app.fastmail.com
** All postings, unless explicitly stated otherwise, are the opinions of the
author, and do not constitute legal or medical advice. This statement is added
to the messages for those lawyers who are too stupid to see the obvious.
Equation solving from VFP
I have the following equation Vb = Va*[(Ca/(1 + H/Ka) - H + Kw/H)/(Cb/(1 + Kw⁄ (H*Kb)) + H - Kw/H)] Va, Ca, Ka, Cb, Kb and Kw are known or can be provided for any given "run" of the calculation. Typical values might be Va = 10, Ca = 0.1, Ka = 1.8E-5, Cb = 0.1, Kb = 0.63, Kw = 1.0E-14 The aim is to calculate H for various values of Vb and this requires "solving" for H. Various software packages do this in pretty much the same way but the terminology varies: Matlab uses "fsolve", Mathcad uses "find", Maple uses "solve" and Excel uses "GoalSeek". I would like to try to find a way of doing this from VFP. Perhaps there is already a .NET DLL that could be called from VFP? Perhaps with a wrapper to act as a sort of mediator? Failing that, would it be a major task to create something in .NET (perhaps using an existing package)? I really don't know, just thinking aloud ... Paul Newton ___ Post Messages to: ProFox@leafe.com Subscription Maintenance: https://mail.leafe.com/mailman/listinfo/profox OT-free version of this list: https://mail.leafe.com/mailman/listinfo/profoxtech Searchable Archive: https://leafe.com/archives This message: https://leafe.com/archives/byMID/9293d867-e260-f2a4-3a38-e96d33394...@gmail.com ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
