projection-matrix

问题 I'm trying to calculate in R a projection matrix P of an arbitrary N x J matrix S : P = S (S'S) ^ -1 S' I've been trying to perform this with the following function: P <- function(S){ output <- S %*% solve(t(S) %*% S) %*% t(S) return(output) } But when I use this I get errors that look like this: # Error in solve.default(t(S) %*% S, t(S), tol = 1e-07) : # system is computationally singular: reciprocal condition number = 2.26005e-28 I think that this is a result of numerical underflow and/or

问题 all, I've got an iphone project that draws a 3D model using OpenGL-ES for a given model view matrix and given projection matrix. I needed to replace 3D model with CALayer, so I put values of model view matrix into CATransform3D structure and assigned it to layer.transform . It worked well, layer was visible and moved on the screen as expected, but after some time I realized that my layers behavior is not precise enough and I should take projection matrix into account. And then a problem