viewof A = {
let A = Eigen.Matrix.zeros([2, nbForces], invalidation);
let ax = nodeLocation[0];
let ay = nodeLocation[1];
for (let i = 0; i < nbForces; i++) {
let bx = adjointNodeLocations[i][0];
let by = adjointNodeLocations[i][1];
let length = 0.0;
let directionX = 0.0;
let directionY = 0.0;
A.set(0, i, directionX);
A.set(1, i, directionY);
}
return A.show('A');
}