Obtaining an invertible square matrix from a nonsquare matrix of full rank in numpy or matlab
By : user2237357
Date : March 29 2020, 07:55 AM
help you fix your problem Assume you have an NxM matrix A of full rank, where M>N. If we denote the columns by C_i (with dimensions Nx1), then we can write the matrix as , Easy, peasy in MATLAB. Use QR, specifically, the pivoted QR. code :
M = [3 0 0 0 0;
0 0 1 0 0;
0 0 0 0 1;
0 2 0 0 0]
[Q,R,E] = qr(M)
Q =
1 0 0 0
0 0 1 0
0 0 0 1
0 1 0 0
R =
3 0 0 0 0
0 2 0 0 0
0 0 1 0 0
0 0 0 1 0
E =
1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 0 1
0 0 0 1 0
M*E
ans =
3 0 0 0 0
0 0 1 0 0
0 0 0 1 0
0 2 0 0 0

Generic Simple 3D Matrix Rotation Issue
By : Adore Infotech
Date : March 29 2020, 07:55 AM
help you fix your problem It appears you have a problem with the order of transformations. Unlike numerical multiplication, matrix multiplication is not commutative. 3D applications are very sensitive to the order of transformations. In English:

simple Inplace square matrix clockwise rotation in java  what is wrong with my code
By : fuse
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , In your second for loop, you are using the wrong variable. Change this: code :
for (int i=0; i<m;i++) {
for (int k=0; k<m;k++) {
^
int temp = arr[i][k];
arr[i][k] = arr[k][i];
arr[k][i] = temp;
for (int i=0; i<m;i++) {
for (int k=i; k<m;k++) {
^
int temp = arr[i][k];
arr[i][k] = arr[k][i];
arr[k][i] = temp;

matrix non uniform scale rotation issue
By : Cf Ayfa
Date : March 29 2020, 07:55 AM

Why android.Matrix.setRotateM returns a matrix whose rotation direction is the opposite of the expected rotation matrix?
By : user2916414
Date : March 29 2020, 07:55 AM
To fix this issue It is because OpenGL (ES) matrices are specified by vectors in column major order. See android.opengl.Matrix: code :
m[offset + 0] m[offset + 4] m[offset + 8] m[offset + 12]
m[offset + 1] m[offset + 5] m[offset + 9] m[offset + 13]
m[offset + 2] m[offset + 6] m[offset + 10] m[offset + 14]
m[offset + 3] m[offset + 7] m[offset + 11] m[offset + 15]
mat4(float, float, float, float, // first column
float, float, float, float, // second column
float, float, float, float, // third column
float, float, float, float); // fourth column
mat4 m44 = mat4(
vec4( Xx, Xy, Xz, 0.0),
vec4( Yx, Xy, Yz, 0.0),
vec4( Zx Zy Zz, 0.0),
vec4( Tx, Ty, Tz, 1.0) );
0 1 0 0 // x axis vector
1 0 0 0 // y axis vector
0 0 1 0 // z axis vector
0 0 0 1 // translation vector

