Examples with Matrix3d maspack.matrix.Matrix3d used on opensource projects

Example 11 with Matrix3d

use of maspack.matrix.Matrix3d in project artisynth_core by artisynth.

the class FemMuscleModel method computeAverageFiberDirection.

/**
 * Computes the average fiber direction in the vicinity of a point based on
 * the line segments contained in a PolylineMesh. Returns the number of
 * supporting line segments used for the calculation. If no segments were
 * found, the method returns 0 and the direction is undefined.
 *
 * @param dir returns the normalized direction
 * @param pos position at which direction should be computed
 * @param rad radius of influence within which polyline mesh segments are
 * considerd
 * @param mesh mesh containing line segments used to determine the direction
 * @return number of supporting line segment
 */
public static int computeAverageFiberDirection(Vector3d dir, Point3d pos, double rad, PolylineMesh mesh) {
    BVTree bvh = mesh.getBVTree();
    ArrayList<BVNode> nodes = new ArrayList<BVNode>();
    Matrix3d cov = new Matrix3d();
    SVDecomposition3d svd = new SVDecomposition3d();
    Vector3d tmp = new Vector3d();
    Matrix3d tmp2 = new Matrix3d();
    bvh.intersectSphere(nodes, pos, rad);
    dir.setZero();
    int nsegs = 0;
    // for computing sign of direction vector
    Vector3d segmentSum = new Vector3d();
    // System.out.println("p=[");
    for (BVNode n : nodes) {
        Boundable[] elements = n.getElements();
        for (int i = 0; i < elements.length; i++) {
            LineSegment seg = (LineSegment) elements[i];
            seg = getSegmentInsideSphere(seg, pos, rad);
            if (seg != null) {
                tmp.sub(seg.myVtx1.pnt, seg.myVtx0.pnt);
                if (tmp.norm() >= 1e-8 * rad) {
                    // System.out.println(seg.myVtx0.getPosition() + " " +
                    // seg.myVtx1.getPosition());
                    nsegs++;
                    // prepare to average directions using SVD
                    computeCov(tmp2, tmp);
                    cov.add(tmp2);
                    segmentSum.add(tmp);
                }
            }
        }
    }
    if (nsegs > 0) {
        // we are technically including both +/- directions, so
        // we have twice the number of points
        cov.scale(2.0 / (2.0 * nsegs - 1));
        try {
            svd.factor(cov);
        } catch (Exception e) {
        // System.err.println(e.getMessage());
        }
        // principal components
        tmp2 = svd.getU();
        tmp2.getColumn(0, dir);
        dir.normalize();
        // most line segments
        if (dir.dot(segmentSum) < 0) {
            dir.scale(-1);
        }
        return nsegs;
    } else {
        return 0;
    }
}

Example 12 with Matrix3d

use of maspack.matrix.Matrix3d in project artisynth_core by artisynth.

the class LinearMaterialCache method addInitialStiffness.

/**
 * Computes and stores the initial stiffness K0 and force f0 terms
 * @param e   element
 * @param mat linear material
 */
public void addInitialStiffness(FemElement3d e, FemMaterial mat) {
    SolidDeformation def = new SolidDeformation();
    def.setAveragePressure(0);
    def.setF(Matrix3d.IDENTITY);
    def.setR(Matrix3d.IDENTITY);
    // compute stiffness matrix
    Matrix6d D = new Matrix6d();
    IntegrationPoint3d[] ipnts = e.getIntegrationPoints();
    IntegrationData3d[] idata = e.getIntegrationData();
    for (int k = 0; k < ipnts.length; k++) {
        IntegrationPoint3d pt = ipnts[k];
        IntegrationData3d dt = idata[k];
        double dv0 = dt.myDetJ0 * pt.getWeight();
        if (dt.myScaling != 1) {
            dv0 *= dt.myScaling;
        }
        Matrix3d Q = dt.myFrame == null ? Matrix3d.IDENTITY : dt.myFrame;
        Vector3d[] GNx0 = pt.updateShapeGradient(dt.myInvJ0);
        // compute tangent matrix under zero stress
        mat.computeTangent(D, SymmetricMatrix3d.ZERO, def, Q, null);
        FemNode3d[] nodes = e.getNodes();
        for (int i = 0; i < nodes.length; i++) {
            for (int j = 0; j < nodes.length; j++) {
                FemUtilities.addMaterialStiffness(K0[i][j], GNx0[i], D, GNx0[j], dv0);
            }
        }
    }
    // initial RHS
    Vector3d tmp = new Vector3d();
    FemNode3d[] nodes = e.getNodes();
    for (int i = 0; i < nodes.length; i++) {
        tmp.setZero();
        for (int j = 0; j < nodes.length; j++) {
            K0[i][j].mulAdd(tmp, nodes[j].getRestPosition(), tmp);
        }
        f0[i].set(tmp);
    }
}

Example 13 with Matrix3d

use of maspack.matrix.Matrix3d in project artisynth_core by artisynth.

the class FemNodeNeighbor method addPressureStiffness.

public void addPressureStiffness(Vector3d gi, double p, Vector3d gj, double dv) {
    if (FemModel3d.noIncompressStiffnessDamping) {
        if (myKX == null) {
            myKX = new Matrix3d();
        }
        FemUtilities.addPressureStiffness(myKX, gi, p, gj, dv);
        FemUtilities.addPressureStiffness(myK, gi, -p, gj, dv);
    }
}

Example 14 with Matrix3d

use of maspack.matrix.Matrix3d in project artisynth_core by artisynth.

the class NeoHookeanMaterial method main.

public static void main(String[] args) {
    NeoHookeanMaterial mat = new NeoHookeanMaterial();
    SolidDeformation def = new SolidDeformation();
    Matrix3d Q = new Matrix3d();
    def.setF(new Matrix3d(1, 3, 5, 2, 1, 4, 6, 1, 2));
    Matrix6d D = new Matrix6d();
    SymmetricMatrix3d sig = new SymmetricMatrix3d();
    mat.setYoungsModulus(10);
    mat.computeStress(sig, def, Q, null);
    mat.computeTangent(D, sig, def, Q, null);
    System.out.println("sig=\n" + sig.toString("%12.6f"));
    System.out.println("D=\n" + D.toString("%12.6f"));
}

Example 15 with Matrix3d

use of maspack.matrix.Matrix3d in project artisynth_core by artisynth.

the class OgdenMaterial method main.

public static void main(String[] args) {
    OgdenMaterial mat = new OgdenMaterial();
    SolidDeformation def = new SolidDeformation();
    Matrix3d Q = new Matrix3d();
    def.setF(new Matrix3d(1.1, 0.1, 0.2, 0.3, 0.8, 0.23, 0.3, 0.1, 1.5));
    Matrix6d D = new Matrix6d();
    SymmetricMatrix3d sig = new SymmetricMatrix3d();
    // double[] alpha = {2.0, 2.0, 2.0, 2.0, 2.0, 2.0};
    // double[] mu = {200.0, 0.0, 0.0, 0.0, 0.0, 0.0};
    mat.computeStress(sig, def, Q, null);
    System.out.println("sig=\n" + sig.toString("%12.6f"));
    mat.computeTangent(D, sig, def, Q, null);
    System.out.println("D=\n" + D.toString("%12.6f"));
}