Dear Leonard - thanks a lot for the solution! Yes, you are right: pH is
presumed known, so the effort is repeated at a series of chosen pH
values. It appears that no matter x0 the estimate for atp is always
-6.239560e-01 which even accounting for offset of 0.008 is negative
which is not possib
Dear Troels,
There might be an error in one of the eqs:
# [modified] TODO: check;
mg2atp <- 10^(-7)*Mg*mgatp;
This version works:
x0 = c(
atp = 0.008,
adp = 0.1,
pi = 0.003,
pcr = 0.042,
cr = 0.004,
lactate = 0.005
) / 30;
# solved the positive value
x0[1] = 1E
Dear Troels,
I send you an updated version of the response. I think that a hybrid
approach is probably the best solution:
- Input / Starting values = free: ATP, ADP, Crea, CreaP, lactate,
inorganic phosphate;
- Output: diff(Total, given total value);
- I assume that the pH is given;
- I did NOT
If the equations are in the form shown in your post then take the log of
both sides, expand the logs and replace log(whatever) with new variables so
now the equations are in linear form and are easy to solve.
__
R-help@r-project.org mailing list -- To UN
,timothy%20aaron%22%20%3cteb...@ufl.edu%3e>>,
Valentin Petzel
mailto:valentin%20petzel%20%3cvalen...@petzel.at%3e>>
Subject: Re: [R] R emulation of FindRoot in Mathematica
Date: Thu, 19 Jan 2023 16:18:57 +0100
Hi Jeff - that is definitely not fair, this is a highly respected
scie
If you need to solve a nonlinear system of equations you could have a look at
the
CRAN Task View: Numerical Mathematics:
https://cran.r-project.org/view=NumericalMathematics
Specifically look in the subsection "Root Finding and Fixed Points".
Berend Hasselman
> On 19 Jan 2023, at 10:41,
verify how the numbers out were calculated so
they must be correct" approach to analysis does not really work for me.
Tim
-Original Message-
From: R-help On Behalf Of Troels Ring
Sent: Thursday, January 19, 2023 9:18 AM
To: Valentin Petzel ; r-help mailing list
Subject: Re: [R
elp mailing list
Subject: Re: [R] R emulation of FindRoot in Mathematica
[External Email]
Thanks, Valentin for the suggestion. I'm not sure I can go that way. I
include below the statements from the paper containing the knowledge on the
basis of which I would like to know at specified [H
From: R-help On Behalf Of Troels Ring
>Sent: Thursday, January 19, 2023 9:18 AM
>To: Valentin Petzel ; r-help mailing list
>
>Subject: Re: [R] R emulation of FindRoot in Mathematica
>
>[External Email]
>
>Thanks, Valentin for the suggestion. I'm not sure I can go that way
Re: [R] R emulation of FindRoot in Mathematica
[External Email]
Thanks, Valentin for the suggestion. I'm not sure I can go that way. I
include below the statements from the paper containing the knowledge on the
basis of which I would like to know at specified [H] the concentration of ea
R-help On Behalf Of Troels Ring
Sent: Thursday, January 19, 2023 9:18 AM
To: Valentin Petzel ; r-help mailing list
Subject: Re: [R] R emulation of FindRoot in Mathematica
[External Email]
Thanks, Valentin for the suggestion. I'm not sure I can go that way. I
include below the statements
Thanks, Valentin for the suggestion. I'm not sure I can go that way. I
include below the statements from the paper containing the knowledge on
the basis of which I would like to know at specified [H] the
concentration of each of the many metabolites given the constraints. I
have tried to cont
Hello Troels,
As fair as I understand you attempt to numerically solve a system of non linear
equations
in multiple variables in R. R does not provide this functionality natively, but
have you tried
multiroot from the rootSolve package:
https://cran.r-project.org/web/packages/rootSolve/rootSo
Hi friends - I hope this is not a misplaced question. From the
literature (Kushmerick AJP 1997;272:C1739-C1747) I have a series of
Mathematica equations which are solved together to yield over different
pH values the concentrations of metabolites in skeletal muscle using the
Mathematica functio
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