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% File src/library/stats/man/SSmicmen.Rd
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% File src/library/stats/man/SSmicmen.Rd
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% Part of the R package, https://www.R-project.org
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% Part of the R package, https://www.R-project.org
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% Copyright 1995-2010 R Core Team
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% Copyright 1995-2017 R Core Team
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% Distributed under GPL 2 or later
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% Distributed under GPL 2 or later
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\name{SSmicmen}
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\name{SSmicmen}
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\encoding{UTF-8}
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\encoding{UTF-8}
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\title{Self-Starting Nls Michaelis-Menten Model}
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\title{Self-Starting Nls Michaelis-Menten Model}
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\seealso{\code{\link{nls}}, \code{\link{selfStart}}
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\seealso{\code{\link{nls}}, \code{\link{selfStart}}
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}
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}
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\examples{
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\examples{
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PurTrt <- Puromycin[ Puromycin$state == "treated", ]
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PurTrt <- Puromycin[ Puromycin$state == "treated", ]
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SSmicmen(PurTrt$conc, 200, 0.05)  # response only
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SSmicmen(PurTrt$conc, 200, 0.05)  # response only
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Vm <- 200; K <- 0.05
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local({  Vm <- 200; K <- 0.05
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SSmicmen(PurTrt$conc, Vm, K)      # response and gradient
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  SSmicmen(PurTrt$conc, Vm, K)    # response _and_ gradient
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})
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print(getInitial(rate ~ SSmicmen(conc, Vm, K), data = PurTrt), digits = 3)
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print(getInitial(rate ~ SSmicmen(conc, Vm, K), data = PurTrt), digits = 3)
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## Initial values are in fact the converged values
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## Initial values are in fact the converged values
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fm1 <- nls(rate ~ SSmicmen(conc, Vm, K), data = PurTrt)
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fm1 <- nls(rate ~ SSmicmen(conc, Vm, K), data = PurTrt)
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summary(fm1)
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summary(fm1)
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## Alternative call using the subset argument
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## Alternative call using the subset argument
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fm2 <- nls(rate ~ SSmicmen(conc, Vm, K), data = Puromycin,
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fm2 <- nls(rate ~ SSmicmen(conc, Vm, K), data = Puromycin,
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           subset = state == "treated")
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           subset = state == "treated")
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summary(fm2)
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summary(fm2) # The same indeed:
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stopifnot(all.equal(coef(summary(fm1)), coef(summary(fm2))))
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\dontshow{
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require(graphics)
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## Visualize the SSmicmen()  Michaelis-Menton model parametrization :
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  xx <- seq(0, 5, len = 101)
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  xx <- seq(0, 5, len = 101)
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  yy <- 5 * xx/(1+xx)
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  yy <- 5 * xx/(1+xx)
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  stopifnot(all.equal(yy, SSmicmen(xx, Vm = 5, K = 1)))
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  require(graphics)
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  par(mar = c(0, 0, 3.5, 0))
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  op <- par(mar = c(0, 0, 3.5, 0))
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  plot(xx, yy, type = "l", axes = FALSE, ylim = c(0,6), xlim = c(-1, 5),
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  plot(xx, yy, type = "l", lwd = 2, ylim = c(-1/4,6), xlim = c(-1, 5),
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       xlab = "", ylab = "", lwd = 2,
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       ann = FALSE, axes = FALSE, main = "Parameters in the SSmicmen model")
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       main = "Parameters in the SSmicmen model")
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  mtext(quote(list(phi[1] == "Vm", phi[2] == "K")))
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  usr <- par("usr")
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  usr <- par("usr")
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  arrows(usr[1], 0, usr[2], 0, length = 0.1, angle = 25)
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  arrows(usr[1], 0, usr[2], 0, length = 0.1, angle = 25)
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  arrows(0, usr[3], 0, usr[4], length = 0.1, angle = 25)
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  arrows(0, usr[3], 0, usr[4], length = 0.1, angle = 25)
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  text(usr[2] - 0.2, 0.1, "x", adj = c(1, 0))
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  text(usr[2] - 0.2, 0.1, "x", adj = c(1, 0))
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  text(-0.1, usr[4], "y", adj = c(1, 1))
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  text(     -0.1, usr[4], "y", adj = c(1, 1))
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  abline(h = 5, lty = 2, lwd = 0)
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  abline(h = 5, lty = 3)
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  arrows(-0.8, 2.1, -0.8, 0, length = 0.1, angle = 25)
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  arrows(-0.8, c(2.1, 2.9),
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  arrows(-0.8, 2.9, -0.8, 5, length = 0.1, angle = 25)
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         -0.8, c(0,   5  ),  length = 0.1, angle = 25)
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  text(-0.8, 2.5, expression(phi[1]), adj = c(0.5, 0.5))
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  text(  -0.8,     2.5, quote(phi[1]))
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  segments(1, 0, 1, 2.7, lty = 2, lwd = 0.75)
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  segments(1, 0, 1, 2.7, lty = 2, lwd = 0.75)
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  text(1, 2.7, expression(phi[2]), adj = c(0.5, 0))
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  text(1, 2.7, quote(phi[2]))
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}
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  par(op)
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}
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}
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\keyword{models}
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\keyword{models}