search for: atan

Hi the following gave me a shock: > atan(2) [1] 1.107149 > atan(2+0i) [1] -0.4636476+0i > or, perhaps more of a gotcha: > atan(1.0001+0i) [1] -0.7853482+0i > atan(0.9999+0i) [1] 0.7853482+0i > evidently atan()'s branch cuts aren't where I thought they were. Where do I look for documentation on this? --...

Hi All, I need some clarifications regarding the mismatch I found in the code and the specification. (a) In the specification, the bark(x) equation is given as: bark(x) = 13.1 atan(.00074x) + 2.24 atan(.0000000158(x^2)) + .0001x whereas in the code it is given as: #define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n)) Which one of these is the proper one ? (b) Also, we are planning to implement a fixed point code for the Vorbis decoder. And as...

Dear R experts. 'D()' function recognizes some of the analitical functions, such as sin, cos, etc. But I'd like to take analytical derivatives from asin, atan etc. functions. Are there any R packages providing that features? Thanks. -- Timur.

Could someone point me to the BARK/MEL tables that these macros (from vorbis/scales.h) are trying to approximate? #define toBARK(f) (13.1*atan(.00074*(f))+2.24*atan((f)*(f)*1.85e-8)+1e-4*(f)) #define fromBARK(z) (102.*(z)-2.*pow(z,2.)+.4*pow(z,3)+pow(1.46,z)-1.) #define toMEL(f) (log(1.+(f)*.001)*1442.695) #define fromMEL(m) (1000.*exp((m)/1442.695)-1000.) I was wondering if I could come up with different functions that were easier...

...m on my machine running R 2.9.0. Any suggestions on what might be causing this and what I can do to avoid it would be very gratefully received. Hoping for some insights Marcus ########################## #Problem example #Works fine: integrate(hazard, 0,Inf, v=0.1, gam=pi*232/200, pos=list(r=5,th=atan(3/4)), a=10, b0=10, bt=0.1) #Gives error "...integral probably divergent": integrate(hazard, 0,Inf, v=0.1, gam=pi*231/200, pos=list(r=5,th=atan(3/4)), a=10, b0=10, bt=0.1) #Plot the integrands - doesn't look obviously problematic h <- hazard(seq(0,500,0.1),0.1,pi*231/200,pos=list...

...of a quadratic form following Imhof's (1961, Biometrika 48) procedure. The parameters are: lambda=c(.6,.3,.1) h=c(2,2,2) sigma=c(0,0,0) q=3 I've implemented Imhof's procedure two ways that, for me, should give the same answer: #more legible integral1 = function(u) { o=(1/2)*sum(h*atan(lambda*u)+sigma^2*lambda*u/(1+lambda^2*u^2)) - q*u/2 rho=prod((1+lambda^2*u^2)^(h/4))*exp( (1/2)*sum((sigma*lambda*u)^2/(1+lambda^2*u^2)) ) integrand = sin(o)/(u*rho) } #same as above integral2= function(u) { ((1/2)*sum(h*atan(lambda*u)+sigma^2*lambda*u/(1+lambda^2*u^2)) - q*u/2)/ (u*(prod((1...

Hi ?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex vectors. Well, I would expect atan2(1,1i) to be equal to atan(-1i), but > atan2(1,1i) Error in atan2(y, x) : Non-numeric argument to mathematical function > R.version _ platform powerpc-apple-darwin8.5....

Hi ?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex vectors. Well, I would expect atan2(1,1i) to be equal to atan(-1i), but > atan2(1,1i) Error in atan2(y, x) : Non-numeric argument to mathematical function > R.version _ platform powerpc-apple-darwin8.5....

...rary x and y values y=x*2-rnorm(1:10) plot(x,y,pch=16,xlim=c(0,10)) #create the graph abline(lm(y~x)) #calculate the y coordinate of the text: yval=predict(lm(y~x),list(x=rep(2,length(x))))[1] #calculate the slope: slope=as.numeric(lm(y~x)[[1]][2]) text(2,yval,"Regression",srt=180/pi*atan(slope),adj=0) #### What am I doing wrong here? Many thanks in advance for any help! Best wishes Christoph (using R 2.6.1 on Windows XP)

..._Name: Morten Welinder Version: snapshot OS: Submission from: (NULL) (65.213.85.129) Two things are wrong. 1. There is nan test outside IEEE_754. 2. The meat part of the function should really be something like... if (!lower_tail) x = -x; if (fabs (x) > 1) { double temp = atan (1 / x) / M_PI; return (x > 0) ? R_D_Clog (temp) : R_D_val (-temp); } else return R_D_val (0.5 + atan (x) / M_PI); ...instead of the current heavily truncated series expansion. The above is much simpler and more precise. (Thanks to Ian Smith for pointing the in-hindsight- obviou...

So I figured out what was going on. The shader has a UMAD TEMP[0].x, TEMP[0].xxxx, -TEMP[5].xxxx, TEMP[0].xxxx instruction, in which the -TEMP[5].xxxx got emitted as cvt neg u32 $r1 u32 $r1 If instead I fudge mkOp() to force a s32 dtype on OP_NEG, everything starts to work. Similarly, if I fudge emitCVT to basically do the same thing, it also works. (Of note -- changing both stype and dtype to

Dear all, I've got a problem with the function atan2. For a couple of coordinates x and y, This function returns the angle between the vector of coordinates (x, y) and the abscissa axis, i.e. it is the same as atan(y/x) (as indicated on the help page). If we consider the vector with coordinates x = 0 and y = 0, we have the following result: &g...

...c, but with no success. Here is an example: m <- 2000 n <- 5000 A <- matrix(rnorm(2*m),ncol=2) B <- matrix(rnorm(2*n),ncol=2) W <- matrix(NA, m, n) for (i in 1:m) { W[i,] <- apply(B, 1, y=A[i,], function(x,y) g(y,x)) } g <- function(x,y){ theta <- atan((y[2]-x[2]) / (y[1] - x[1])) theta + 2*pi*(theta < 0) } Thanks for any suggestions. Best, Ravi. ---------------------------------------------------------------------------- ------- Ravi Varadhan, Ph.D. Assistant Professor, The Center on Aging and Health Division of Geriat...

...bed in the Vorbis specification and its implementation in libvorbis. In the specificationhttp://xiph.org/vorbis/doc/Vorbis_I_spec.pdf bark(x) = 13.1arctan(.00074x) + 2.24arctan(.0000000185x**2 + .0001x) In the libvorbis code http://svn.xiph.org/trunk/vorbis/lib/scales.h #define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n)) You will note that the last term is inside the parentheses of the second arctan function in the specification but outside in the libvorbis implementation. This results in extremely large differences at high frequencies. Which is correct: the spe...

Hi, I'm just wonder if there is an R equivalent function of gam() - which exist in Splus. Also does anyone know if the library( modreg ), which comes with the installation file of R 1.3.0 (Windows version), exists in the previous versions of R (again, Windows version)? Or does one need to install the library into the previous versions of R explicitly? Thanks, Ko-Kang Wang

...d" should match that in S. Group methods for "Math", "Ops" and "Summary" are available. o Complex arithmetic is now implemented. Many mathematical functions are now defined for complex arguments (e.g. sqrt, exp, log, sin, cos, tan, asin, acos, atan). There is no complex gamma function or log gamma function yet. The summary functions "mean", "sum", "prod", "cumsum" and "cumprod" work correctly when (some of) their arguments are complex. Other functions such as "solve&quo...

...d" should match that in S. Group methods for "Math", "Ops" and "Summary" are available. o Complex arithmetic is now implemented. Many mathematical functions are now defined for complex arguments (e.g. sqrt, exp, log, sin, cos, tan, asin, acos, atan). There is no complex gamma function or log gamma function yet. The summary functions "mean", "sum", "prod", "cumsum" and "cumprod" work correctly when (some of) their arguments are complex. Other functions such as "solve&quo...

...d" should match that in S. Group methods for "Math", "Ops" and "Summary" are available. o Complex arithmetic is now implemented. Many mathematical functions are now defined for complex arguments (e.g. sqrt, exp, log, sin, cos, tan, asin, acos, atan). There is no complex gamma function or log gamma function yet. The summary functions "mean", "sum", "prod", "cumsum" and "cumprod" work correctly when (some of) their arguments are complex. Other functions such as "solve&quo...

...ect ratio, but puts the text at the wrong angle if the plot region is short and wide or tall and narrow. I can't find a par() component containing the plot aspect ratio. It will be for png() or postscript() output, if that matters. f <- function(x) x g <- function(x) 2*x (f_angle <- atan(1)*180/pi) (g_angle <- atan(2)*180/pi) xpos <- 0.2 plot(f) plot(g,add=TRUE) par(srt=f_angle) text(xpos,f(xpos),label="y=x",pos=3) par(srt=g_angle) text(xpos,g(xpos),label="y=2x",pos=3) -- Levi Waldron post-doctoral fellow Jurisica Lab, Ontario Cancer Institute Division...

...ined to 2k3 AD. > > >My ideas about why this happens are exausted (all of them are >unproductive >:). >ANYBODY, please, if you have similar, or heard about this >situation, please >let me know. >May be some ideas about fighting against it? > >Thnx in advance. >/aTan > >-- >To unsubscribe from this list go to the following URL and read the >instructions: https://lists.samba.org/mailman/listinfo/samba >