Revision 72984f188f682cc270e18126009c8e56b7aab80d authored by Karline Soetaert on 10 August 2011, 00:00:00 UTC, committed by Gabor Csardi on 10 August 2011, 00:00:00 UTC
1 parent 9100f83
geometries.r
``````## =============================================================================
##
## Surface area and volume of geometries
##
## =============================================================================

# surface and volume of a sphere
g.sphere <- function (x) return(list(surf=4*pi*x*x,vol=4/3*pi*x^3))

# surface and volume of a spheroid
g.spheroid <- function (x, b=1) {     # b = long/short radius
bb <- x*b
te <- acos(b)
if (b < 1)      #oblate
surf <- 2*pi *(x^2 + bb^2 / sin(te)*log((1+sin(te))/cos(te)))
else if (b > 1)
surf <- 2*pi*(x^2 + x*bb*te/sin(te))
else
surf <- 4 * pi*x^2

vol <- 4/3*pi * x^2 * bb
return(list(surf=surf,vol=vol))
}

# surface and volume of a cylinder
g.cylinder <- function (x,L=1) return(list(surf=2*pi*x*L,vol=pi*x^2*L))
``````

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