Displaying 6 results from an estimated 6 matches for "yd1".
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d1
2004 Jun 10
0
lsoda with arbitrary zero thresholds (with psuedo-solution)
...example again I once again highlight the code
> that I have changed to put in place arbitrary thresholds:
> parms <- c(k1=0.04, k2=1e4, k3=3e7)
> my.atol <- c(1e-6, 1e-10, 1e-6)
> times <- seq(0,1000)
> lsexamp <- function(t, y, p)
> {
> if(y[1] < .4) yd1 <- -y[1] ### These if, else statements are new
> else yd1 <- -p["k1"] * y[1] + p["k2"] * y[2]*y[3]
> if(y[3] < .4) yd3 <- -y[3] ### These if,else statements are new
> else yd3 <- p["k3"] * y[2]^2
> list(c(yd1,-yd1-yd3,yd...
2006 Nov 29
2
How to solve differential equations with a delay (time lag)?
...;lsoda"
function "odesolve" package. However, I am not sure how to specify the
delay term using the syntax allowed by odesolve.
Here is an example of the kind of problem that I am trying to solve:
> library(odesolve)
yprime <- function(t, y, p) { # this function
yd1 <- p["k1"] *(t <= p["T"]) - p["k2"] * y[2]
yd2 <- p["k3"] * y[1](t - p["delay"]) - p["k4"] * y[2] # this is not
syntactically valid, but it is what I would like to do
list(c(yd1,yd2))
}
times <- seq(0,30,by=0.1)
y0 <...
2008 Sep 16
0
FW: odesolve dynload example
...hdiff <- function(t, y, p)
{
const=p["const"]
kay =p["kay"]
psii=p["psii"]
m1=p["m1"]
m2=p["m2"]
M=p["M"]
N=p["N"]
T=p["T"]
bexp<-as.brob((const*(psii-m1*y[1]-m2*M/N))/T)
yd1<-as.numeric((kay*exp(bexp))/(kay*t*exp(bexp)+1)-
(kay^2*t*exp(2*bexp))/(kay*t*exp(bexp)+1)^2)
list(c(yd1))
}
Now I guess this could be done with gmp.
Now I use this stuff in the function that odesolve's lsoda refers to,
and
I have found that my approach using pure R code...
2008 Sep 16
0
lsoda( linking to GMP for big numbers from C code)
...hdiff <- function(t, y, p)
{
const=p["const"]
kay =p["kay"]
psii=p["psii"]
m1=p["m1"]
m2=p["m2"]
M=p["M"]
N=p["N"]
T=p["T"]
bexp<-as.brob((const*(psii-m1*y[1]-m2*M/N))/T)
yd1<-as.numeric((kay*exp(bexp))/(kay*t*exp(bexp)+1)-
(kay^2*t*exp(2*bexp))/(kay*t*exp(bexp)+1)^2)
list(c(yd1))
}
Now I guess this could be done with gmp.
Now I use this stuff in the function that odesolve's lsoda refers to,
and I have found that my approach using pure R code...
2004 Jun 14
1
olesolve: stepsize
...*p["kg"]*(p["hgo0"]/p["vg"])/(p["k21"] + p["k01"]
+ p["kl"] - p["k21"]*p["k12"]/(p["k12"] + p["k02"]))/(p["ki"]*p["vi"]))
# G1(t)-y(1); G2(t)-y(2);I(t)-y(3); X(t)-y(4)
yd1 <- (abs(t) + p["hgo0"] - (p["kl"] + p["fx"]*y[4])*y[1]*p["vg"] +
p["k12"]*y[2])/p["vg"] - (p["k21"] + p["k01"])*y[1]
yd2 <- p["k21"]*y[1]*p["vg"] - (p["k12"] + p["k02"...
2009 Jul 23
1
[PATCH server] changes required for fedora rawhide inclusion.
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