search for: geochemist

I'm in e-mail contact with a geochemist who maintains a well regarded geochemistry web site. He's drawing diagrams either with a Turbo Pascal program running in a DOS window or with Excel. I'm trying to persuade him that R would be a better choice. Something he's particularly keen on is ternary diagrams. I think he is tal...

...the most discrimination between the groups as this is important information for me. I struggle to interpret the PCA plot in a way that helps me (due to the large number of elements). So I'm trying to do some sort of step-wise variable selection. I would love to hear from someone (possibly a geochemist or similar) who does this regularly to determine the best course of action in R to do this. Thanks very much -- Gareth Campbell PhD Candidate The University of Auckland P +649 815 3670 M +6421 256 3511 E gareth.campbell@esr.cri.nz gcam032@gmail.com [[alternative HTML version deleted]]

...<- c(1,2,3,4) exmpl <- c(3,3,4,2,3,1,2,3,4,8,8,23,1,2,3,4,4,34,4,3,2,1,1,2,3,4) how do I get the desired answer by finding the occurence of the pattern and returning the starting indices: 6, 13, 23 Suggestions very much appreciated! Kind regards, Matt Redding, Ph.D. Principal Scientist Geochemist/Soil Chemist Queensland Primary Industries & Fisheries DEEDI PO Box 102, Toowoomba, 4350, Qld ph: 0746 881372 fax: 0746 881192 ********************************DISCLAIMER**************...{{dropped:15}}

...top the other and the help page doesn't indicate anyway to position the bar along the y-axis. So does anyone have a nifty trick to to fill in blank gaps? At least my database can check for "overlaping" intervals before I get the data into R. Thanks, Phillip J. Allen Consulting Geochemist/Geologist Lima Peru e-mail: paallen at attglobal.net Phillip, How about this, which will generate a vertical barplot, a y axis from 0 down to 40 meters and bar widths and colors for each segment varied: from <- c(0, 1.2, 4.0, 4.2, 5.0, 25.0, 30.1) to <- c(1.2, 4.0, 4.2, 5.0, 25, 30.1, 3...

...into the evaluation. Any thoughts or suggested alternative directions or shared examination would be welcome. SimonG **************************************************************************** ***************************** Simon Gatehouse Phone: 61 (2) 9490 8677 Geochemist Mobile:61 0407 130 635 CSIRO Exploration & Mining Fax: 61 (2) 9490 8921 Address: CSIRO Division of Exploration and Mining, Newbigin Close off Julius Ave North Ryde, NSW 2113 Mail: CSIRO Division of Exploration and Mining, P....

Dear R-experts, I have 28 data points that I would like to fit with a non linear broken-stick -- with three fitted parameters. When I view trace -- and use the final values as lines on the graph of data -- it looks pretty good. Q1. Why am I getting singular convergeance? Q2. Can you suggest another approach that may prove more satisfying? I have read previous examples on nls and this sort of

...between the groups as this is important information > for me. I struggle to interpret the PCA plot in a way that helps me (due to > the large number of elements). So I'm trying to do some sort of step-wise > variable selection. > > I would love to hear from someone (possibly a geochemist or similar) who > does this regularly to determine the best course of action in R to do this. > > > Thanks very much > > > -- > Gareth Campbell > PhD Candidate > The University of Auckland > > P +649 815 3670 > M +6421 256 3511 > E gareth.campbell@esr.cri.n...