[+] Find and keep only the highest positive part of a curve

Remove negative parts of a curve then find the highest positive part one and, lastly, remove all the remaining smaller ones.

Can be used to treat loadings of principal componenst before using them as initial conditions for MCR-ALS algorythm (e.g. als, doALS).

unipeak(y)

Arguments

y

A vector that represents a curve.

Value

Modified y

See also

Other curves inspHelper: GaussAmp()

Other component analysis / factorisation related functions in spHelper: getScores(), infoDim(), plot_spDiff(), qplot_infoDim(), qplot_kAmp(), qplot_kSp(), qplot_spc(), reconstructSp(), sortLoadings(), whichOutlier()

Author

Vilmantas Gegzna

Examples

#  Example 1 ------------------------------------------------------------------------

x     <- seq(-10,20,.1)
y0    <- sin(x)/3 + GaussAmp(x,c = 7, A = 1.5) -.1
y0NEW <- unipeak(y0)

# Plot the results
par(mfrow = c(1,1))
plot( x, y0,    type = "l", lty = 3,
        main = "'unipeak' keeps positive part \n of highest peak only" );
lines(x, y0NEW, type = "l", lty = 1, lwd = 3);
legend("topleft", legend = c("Before","After"), lty = c(3,1))



#  Example 2 ------------------------------------------------------------------------

x  <- seq(-10,20,.1)
y1 <- (sin(x/4) + GaussAmp(x))
y2 <- (2*sin(x) + sin(x/5) + GaussAmp(x, c = 6))
y  <- base::rbind(y1,y2)

yNEW <- apply(y,1,unipeak)

op <- par(mfrow = c(3,1))

# plot 1
matplot(x, t(y), type = "l", lty = 3,  main = "A - Initial curves");
abline(h = 0)

# plot 2
matplot(x,yNEW, type = "l", lty = 1,lwd = 3,
        main = "B - Only the highest positive\n peaks per curve");
abline(h = 0)

# plot 3: both plots together
matplot(x, t(y), type = "l", lty = 3, main = "A and B together");
matlines(x,yNEW, type = "l", lty = 1,lwd = 3);
abline(h = 0)


par(op)