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Use Jacobi preconditioner, not inverse Jacobi

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Irlan 2019-06-14 11:48:34 -03:00
parent 24a86505ee
commit a3a9495d88
1 changed files with 14 additions and 11 deletions
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25
src/bounce/softbody/softbody_solver.cpp
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@ -92,32 +92,35 @@ static void b3ExtractRotation(b3Mat33& out, b3Quat& q, const b3Mat33& A, u32 max
out = b3QuatMat33(q); out = b3QuatMat33(q);
} }
//
static void b3SolveMPCG(b3DenseVec3& x, static void b3SolveMPCG(b3DenseVec3& x,
const b3SparseMat33View& A, const b3DenseVec3& b, const b3SparseMat33View& A, const b3DenseVec3& b,
const b3DenseVec3& z, const b3DiagMat33& S, u32 maxIterations = 20) const b3DenseVec3& z, const b3DiagMat33& S, u32 maxIterations = 20)
{ {
B3_PROFILE("Soft Body Solve Ax = b"); B3_PROFILE("Soft Body Solve MPCG");
// Jacobi preconditioner
// P = diag(A)
b3DiagMat33 P(A.rowCount); b3DiagMat33 P(A.rowCount);
b3DiagMat33 invP(A.rowCount); b3DiagMat33 invP(A.rowCount);
for (u32 i = 0; i < A.rowCount; ++i) for (u32 i = 0; i < A.rowCount; ++i)
{ {
b3Mat33 D = A(i, i); b3Mat33 a = A(i, i);
// Sylvester Criterion to ensure PD-ness // Sylvester Criterion to ensure PD-ness
B3_ASSERT(b3Det(D.x, D.y, D.z) > 0.0f); B3_ASSERT(b3Det(a.x, a.y, a.z) > 0.0f);
B3_ASSERT(D.x.x != 0.0f); B3_ASSERT(a.x.x != 0.0f);
float32 xx = 1.0f / D.x.x; float32 xx = 1.0f / a.x.x;
B3_ASSERT(D.y.y != 0.0f); B3_ASSERT(a.y.y != 0.0f);
float32 yy = 1.0f / D.y.y; float32 yy = 1.0f / a.y.y;
B3_ASSERT(D.z.z != 0.0f); B3_ASSERT(a.z.z != 0.0f);
float32 zz = 1.0f / D.z.z; float32 zz = 1.0f / a.z.z;
P[i] = b3Diagonal(xx, yy, zz); P[i] = b3Diagonal(a.x.x, a.y.y, a.z.z);
invP[i] = b3Diagonal(D.x.x, D.y.y, D.z.z); invP[i] = b3Diagonal(xx, yy, zz);
} }
x = z; x = z;