<Ted.Harding <at> manchester.ac.uk> writes: > > On 21-Sep-09 18:47:50, Oliver Bandel wrote: > > Hello, > > in scilab /Matlab there are functions that can create linear > > sequences (like R's seq()) as well as logarithmic sequences. > > > > > > Is there a logarithmic aequivalent of seq()? > > Or maybe this would be an idea for newer R-releases, > > maybe a type-option with "linear" and "logarithmic" as > > parameters....?! > > > > Ciao, > > Oliver > > If you mean going from a to b by "logarithmically equal" steps, > then you can quite readily implement it yourself. For example: > > exp(log(10)*seq(log10(1),log10(100),by=0.25) > [1] 1.000000 1.778279 3.162278 5.623413 10.000000 > [6] 17.782794 31.622777 56.234133 100.000000 [...]
OK, thanks for the hint. I adapted your example... ...to create a function that offers what scilab's logspace() offers: > logspace <- function( d1, d2, n) exp(log(10)*seq(d1, d2, length.out=n)) > logspace( 1, 2, 10 ) [1] 10.00000 12.91550 16.68101 21.54435 27.82559 35.93814 46.41589 [8] 59.94843 77.42637 100.00000 > logspace( 1, 7.2, 10 ) [1] 1.000000e+01 4.885274e+01 2.386590e+02 1.165914e+03 5.695811e+03 [6] 2.782559e+04 1.359356e+05 6.640828e+05 3.244226e+06 1.584893e+07 > But maybe your example (with the logarithms of the arguments) make even more sense... :-) Ciao, Oliver ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
