similar to: a question about the computation of expression

Hi, To my knowledge, Ryacas can do symbolic computation in R, like Mathematica or Maple. I wonder if it (or any other R package) can solve symbolically a system of equations? I have a system of four equations in four variables (non-linear, but not very hard to solve) and wonder if Ryacas or any other package can do it. I do not find the solution in Ryacas. Can it find a symbolic solution

If there are many character variables,and I want to get the mosaic plot of every pair of each variable,how to do then? If the variables are numeric, I can use pairs to get paired scatter plot. But as to the character variables, how to get the "paired mosaic plot"? Many thanks. -- QQ: 1733768559 At 2015-02-07 17:04:26,"Jim Lemon" <drjimlemon at gmail.com>

hi all: Here's a dataframe(dat) and a vector(z): dat: x1 x2 x3 0.2 1.2 2.5 0.5 2 5 0.8 3 6.2 > z [1] 10 100 100 I wanna do the following: 10*x1,100*x2,1000*x3 My solution is using the loop for z and dat(since the length of z is the same as ncol of dat),which is tedious. I wanna an efficient solution to do it . Any help? Many thanks! My best

Hi,all: I want to perform multiple correspondance analysis via MCA{FactoMineR}. The data is in the attachment. My code: dat<-read.delim("e:\\mydata.txt",header=T) MCA(dat,quanti.sup=7,quali.sup=1:6) Error in `[.data.frame`(tab, , i) : undefined columns selected My question: Why does the error happen? Many thanks. Best. -------------- next part -------------- An embedded and

Hi,all: I met a problem of nls. My data: x y 60 0.8 80 6.5 100 20.5 120 45.9 I want to fit exp curve of data. My code: > nls(y ~ exp(a + b*x)+d,start=list(a=0,b=0,d=1)) Error in nlsModel(formula, mf, start, wts) : singular gradient matrix at initial parameter estimates I can't find out the reason for the error. Any suggesions are welcome. Many thanks. [[alternative HTML

Dear Friends. I have a very long expression and I use function D to find its derivative, which will be even longer. I save the resulting expression in a variavle, say bbb. But when I tried to display bbb on the screen, the R screen is not long enough for me to view it. Is there a way to save the expression to a file? Best Wishes Yuchen Luo [[alternative HTML version deleted]]

Hi I am currently (for pedagogical purposes) writing a simple numerical analysis library in R. I have come unstuck when writing a simple Newton-Raphson implementation, that looks like this: f <- function(x) { 2*cos(x)^2 + 3*sin(x) + 0.5 } root <- newton(f, tol=0.0001, N=20, a=1) My issue is calculating the symbolic derivative of f() inside the newton() function. I cant seem to get R to

Hi all: My data is in the attachment. I want to analysis the mean difference of y between 2 sex. My code: result_lm<-lm(y~factor(sex) + x1 + x2) summary(result_lm) The result of "factor(sex)m" 136.83, is the mean difference of y between 2 sex,and the corresponding p value is 0.07618. My question is: how to get the mean y of sex(m) and sex(f) respectively via lm function? Many

Dear R-gurus, I know that it is not a R problem, but as need to implement some solution for this on R, I would like to know if someone help me on how to isolate X on the expression below. K=(sen A * sen B ) + ( cos A * cos B * cos ( X - Y ) ) Any help are welcome mitinho astronauta brazil [[alternative HTML version deleted]]

Hi all: I have a question about multi-comparison. The data is in the attachment. My purpose: Compare the predicted means of the 3 methods(a,b,c) pairwisely. I have 3 ideas: #idea1 result_aov<-aov(y~ method + x1 + x2) TukeyHSD(result_aov) diff lwr upr p adj b-a 0.845 0.5861098 1.1038902 0.0000001 c-a 0.790 0.5311098 1.0488902 0.0000002 c-b -0.055 -0.3138902

Hi all: If there are two numeric variable:x,y, and I can get paired scatter plot by function "pairs".But if x and y are character, and I want to get paired mosaic plot,which function should be used then? Many thanks! My best. -- QQ: 1733768559 [[alternative HTML version deleted]]

I am having following problem: I?m constructing model for calculation of area of triangle. I know sides a, b, and gamma angle. I wish to calculate the area using heron?s formula: S <- sqrt(s*(s-a)*(s-b)*(s-c)) where s <- (a+b+c)/2 and c is calculated using law of cosines: c <- sqrt(a^2 + b^2 -2*a*b*cos(gamma)) since i am calculating a regression model, i need derivation of this

Hi all, I am trying to implement the following matlab code with Ryacas : syms U x x0 C d1=diff(U/(1+exp(-(x-x0)/C)),x); pretty(d1) d2=diff(U/(1+exp(-(x-x0)/C)),x,2); pretty(d2) solx2 = solve(d2 == 0, x, 'Real', true) pretty(solx2) slope2=subs(d1,solx2) I have tried the following : library(Ryacas) x <- Sym("x");U <- Sym("U");x0 <-

Thanks for the response. Yes, I did study the vignette but did not understand it fully. Anyway, I have tried once again now. I am happy to say that I have got what I wanted. library(Ryacas) x <- Sym("x");U <- Sym("U");x0 <- Sym("x0");C <- Sym("C") my_func <- function(x,U,x0,C) { return (U/(1+exp(-(x-x0)/C)))} FirstDeriv <-

Have you studied the "Introduction to Ryacas" vignette that come with the package? Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Tue, Sep 19, 2017 at 2:37 AM, Vivek Sutradhara <viveksutra at gmail.com> wrote:

Bonjour. Je n''ai pas encore eu l''occasion d''utiliser TE_RICH2 en plus de TE_RICH | TE_MULTILINE, je compte l''essayé. Pour rentrer le texte dans TextCtrl j''utilise : @dou << texte Sebastien _______________________________________________ wxruby-users mailing list wxruby-users@rubyforge.org http://rubyforge.org/mailman/listinfo/wxruby-users

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

Salut alex, j''utilise ce bout de code pour faire apparaître mon texte dans ma fenêtre: @dou = TextCtrl.new(@s, -1, "", Point.new(10, 70), Size.new(410, 210), TE_RICH | TE_MULTILINE) @dou << "je vais à l''école" le problème c''est que l''encodage ne marche pas.Je ne peut pas mettre l''accentuation.J''ai essayer pas mal de