If you want to rotate a vector you should construct what is known as a rotation matrix. Rotation in 2D Say you want to rotate a vector or a point by θ, then trigonometry states that the new coordinates are To demo this, let’s take the cardinal axes X and Y; when we rotate the X-axis 90° counter-clockwise, … Read more
Given using LinearAlgebra, the most julianic way of expressing the identity matrix is: This answer may seem trite, but it is also kind of profound. The whole point of the operator I is that in the vast majority of cases where users want an identity matrix, it is not necessary to actually instantiate that matrix. Let’s say you want … Read more
In case you still haven’t found an answer, or in case someone in the future has this question. To solve Ax=b: numpy.linalg.solve uses LAPACK gesv. As mentioned in the documentation of LAPACK, gesv requires A to be square: LA_GESV computes the solution to a real or complex linear system of equations AX = B, where A is a square … Read more
There are quite a few projects that have settled on the Generic Graphics Toolkit for this. The GMTL in there is nice – it’s quite small, very functional, and been used widely enough to be very reliable. OpenSG, VRJuggler, and other projects have all switched to using this instead of their own hand-rolled vertor/matrix math. I’ve found … Read more
I need to solve a set of simultaneous equations of the form Ax = B for x. I’ve used the numpy.linalg.solve function, inputting A and B, but I get the error ‘LinAlgError: Last 2 dimensions of the array must be square’. How do I fix this? Here’s my code: The values of the matrix/vector are calculated earlier in … Read more