igl.cotmatrix(V,F,L)
igl.massmatrix(V,F,igl.MASSMATRIX_TYPE_VORONOI,M)
igl.invert_diag(M,Minv)

# Bi-Laplacian
Q = L * (Minv * L);

# Zero linear term
B = igl.eigen.MatrixXd.Zero(V.rows(),1);

Z       = igl.eigen.MatrixXd()
Z_const = igl.eigen.MatrixXd()

# Alternative, short hand
mqwf = igl.min_quad_with_fixed_data()

# Empty constraints
Beq = igl.eigen.MatrixXd()
Aeq = igl.eigen.SparseMatrixd()

igl.min_quad_with_fixed_precompute(Q,b,Aeq,True,mqwf)
igl.min_quad_with_fixed_solve(mqwf,B,bc,Beq,Z)

# Constraint forcing difference of two points to be 0
Aeq = igl.eigen.SparseMatrixd(1,V.rows())

# Right hand, right foot
Aeq.insert(0,6074,1)
Aeq.insert(0,6523,-1)
Aeq.makeCompressed()
igl.slice(L, vin, b, L_in_b)

# Dirichlet boundary conditions from z-coordinate
bc = igl.eigen.MatrixXd()
Z = V.col(2)
igl.slice(Z, b, bc)

# Solve PDE
solver = igl.eigen.SimplicialLLTsparse(-L_in_in)
Z_in = solver.solve(L_in_b * bc)

# slice into solution
igl.slice_into(Z_in, vin, Z)

# Alternative, short hand
mqwf = igl.min_quad_with_fixed_data()

# Linear term is 0
B = igl.eigen.MatrixXd()
B.setZero(V.rows(), 1)

# Empty constraints
Beq = igl.eigen.MatrixXd()
Aeq = igl.eigen.SparseMatrixd()

# Our cotmatrix is _negative_ definite, so flip sign
igl.min_quad_with_fixed_precompute(-L, b, Aeq, True, mqwf)
igl.min_quad_with_fixed_solve(mqwf, B, bc, Beq, Z)

# Pseudo-color based on solution
C = igl.eigen.MatrixXd()