sorry folks I have been missing in action, I will take a look as soon as I
can.
Sameer


On Sat, Jun 6, 2020 at 12:26 PM Wood, Tobias <[email protected]> wrote:

> Hello,
>
>
>
> I have opened an issue here:
> https://gitlab.com/libeigen/eigen/-/issues/1912
>
>
>
> I remembered that I did previously discuss the .exp() issue with Sameer on
> the Ceres mailing list, I have added a link to that, however I am now
> getting a slightly different error message because it looks like the
> internals of the STL have changed. Also, I have changed my algorithm
> slightly and now only need .pow(), but this does not work with Jets either.
> I think the problem with .pow() looks easier to fix?
>
>
>
> Thanks,
>
> Toby
>
>
>
> *From: *Rasmus Munk Larsen <[email protected]>
> *Reply to: *"[email protected]" <[email protected]>
> *Date: *Thursday, 4 June 2020 at 18:46
> *To: *eigen <[email protected]>, Sameer Agarwal <
> [email protected]>
> *Subject: *Re: [eigen] Using Eigen decompositions with ceres autodiff Jet
> data type.
>
>
>
> Hi Tobias,
>
> Please do. Sameer, since this is Ceres solver related, could I ask you to
> help out with this issue.
>
> Rasmus
>
>
>
> On Thu, Jun 4, 2020 at 3:06 AM Wood, Tobias <[email protected]> wrote:
>
> Hello,
>
>
>
> Apologies to bring up a tangentially related topic - Eigen's matrix
> exponential also doesn't work with Ceres Jets. There is some code inside
> the matrix exponential that checks if the scalar type is "known" to Eigen,
> I assume because there are some constants it requires. Jet<double> is not
> one of those types, so Eigen refuses to compile. When I encountered this
> problem earlier this year I worked around it by using Ceres numeric
> differentiation, but obviously if there's a chance to fix this and use
> auto-differentiation I would be very happy (big speed increase hopefully).
> Should I create an issue on the Eigen gitlab?
>
>
>
> Thanks,
>
> Toby
>
>
>
> *From: *Oleg Shirokobrod <[email protected]>
> *Reply to: *"[email protected]" <[email protected]>
> *Date: *Thursday, 4 June 2020 at 06:36
> *To: *"[email protected]" <[email protected]>
> *Subject: *Re: [eigen] Using Eigen decompositions with ceres autodiff Jet
> data type.
>
>
>
> 1. I would like to have autodiff ability, so I cannot use double for both
> A and b. If I cast b: A.jacobiSVD().solve( b.cast<T>()) everything works
> fine, but BinOp(T,T) is more expensive than BinOp(T, double). I would like
> to keep b as a vector of doubles.
>
> 2. T=Jet is ceres solver autodiff implementation type. There is a trait
> definition for Jet binary operations for type deduction such that
> type(Jet*double) = Jet and so on. It works when I do direct multiplication 
> VS^-1U^T
> * b. It works similar to complex scalar matrices and double rhs and there
> is the same problem for complex scalar cases.
>
> 3. I think that the mixed type deduction rule should give the same type
> for VS^-1U^T * b and  for A.jcobianSVD().solve(b); where A = USV^T because
> both use the same algorithm.
>
> 4. Unless there are serious reasons, deduction rules should be similar to
> scalar type equations. complex<double> A; double b; x = A^-1 * b; type(x) =
> complex<double>.
>
>
>
> On Wed, Jun 3, 2020 at 11:16 PM Rasmus Munk Larsen <[email protected]>
> wrote:
>
> Try to compile your code in debug mode with the type assertions on.
>
>
>
> On Wed, Jun 3, 2020 at 1:14 PM Rasmus Munk Larsen <[email protected]>
> wrote:
>
> Are you saying that you compute the decomposition in one type and solve
> with a RHS of a different type? Why do you say that VS^-1U^T * b should be
> Matrix<T>? That makes an assumption about type coercion rules. In fact, you
> cannot generally mix types in Eigen expressions without explicit casting,
> and U.adjoint() * b should fail if the types are different.
>
>
>
> On Wed, Jun 3, 2020 at 11:33 AM Oleg Shirokobrod <
> [email protected]> wrote:
>
> Rasmuss, I do not quite understand this issue. Decomposition solve should
> propagate scalar type of a matrix but not scalar type of its argument.
> Example:
>
> template <typename T> Matrix<T> A;
>
> VectorXd b;
>
> A.jcobiSVD().solve(b) should be of type Matrix<T> but it is not. Type of
> result is Matrix<double>. If we make SVD decomposition of A = USV^T and
> express result as VS^-1U^T * b, than result will be of type Matrix<T>.
> Which is correct and differs from result of solve which uses the same
> algorithm but more complex result’s type deduction. This is the problem.
>
>
>
> On Wed 3. Jun 2020 at 20.19, Rasmus Munk Larsen <[email protected]>
> wrote:
>
> OK, I opened https://gitlab.com/libeigen/eigen/-/issues/1909
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.com%2Flibeigen%2Feigen%2F-%2Fissues%2F1909&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=4adEoOhABpJiEJlKW29VCAHkhG4EXH6ZnSeSQr8dmJ0%3D&reserved=0>
>  for
> this.
>
>
>
> On Tue, Jun 2, 2020 at 11:06 PM Oleg Shirokobrod <
> [email protected]> wrote:
>
> Yes. At the time of computing only 1d observation (VectorXd) is known.
>
>
>
> On Tue, Jun 2, 2020 at 9:42 PM Rasmus Munk Larsen <[email protected]>
> wrote:
>
> OK, so b is declared as VectorXf or some other type with
> ColsAtCompileTime=1?
>
>
>
> On Tue, Jun 2, 2020 at 11:27 AM Oleg Shirokobrod <
> [email protected]> wrote:
>
>
>
> Yes, b is measured spectrum that is 1d array. I have to get x for 1d array
> at a time. I fit sum of peak models to 1d rhs. 1d array of peak model
> values is one column of matrix A.
>
>
>
> On Tue 2. Jun 2020 at 20.06, Rasmus Munk Larsen <[email protected]>
> wrote:
>
> Why do you say that? You could be solving for multiple right-hand sides.
> Is b know to have 1 column at compile time?
>
>
>
> On Tue, Jun 2, 2020 at 1:31 AM Oleg Shirokobrod <
> [email protected]> wrote:
>
> Hi Rasmus,
>
>
>
> I have just tested COD decomposition in Eigen library. It arises the same
> problem. This is defect of Eigen decomposition module type reduction of
> result of solve method.  If
>
>  template <typename T> Matrix<T, Dynamic, Dynamic>  A; and ArraXd b;, than
> x = A.solve(b) should be of type  <typename T> Matrix<T, Dynamic, 1.>.
>
>
>
> I like the idea to use COD as an alternative to QR or SVD and I added this
> option to my code.
>
>
>
>
>
> On Tue, Jun 2, 2020 at 10:36 AM Oleg Shirokobrod <
> [email protected]> wrote:
>
> Rasmus, I wiil have a look at COD. Brad, I did not try CppAD.I am working
> in given framework: ceres nonlinear least squares solver + ceres autodiff +
> Eigen decomposition modules SVD or QR. The problem is not just on autodiff
> side. The problem is that Eigen decomposition modul does not work properly
> with autodiff type variable.
>
>
>
> Thank you everybody for advice.
>
>
>
> On Mon, Jun 1, 2020 at 8:41 PM Rasmus Munk Larsen <[email protected]>
> wrote:
>
>
>
>
>
> On Mon, Jun 1, 2020 at 10:33 AM Patrik Huber <[email protected]>
> wrote:
>
> Hi Rasmus,
>
>
>
> This is slightly off-topic to this thread here, but it would be great if
> you added your COD to the list/table of decompositions in Eigen:
> https://eigen.tuxfamily.org/dox/group__TopicLinearAlgebraDecompositions.html
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Feigen.tuxfamily.org%2Fdox%2Fgroup__TopicLinearAlgebraDecompositions.html&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=BeutduNEeXIXTOtbc8%2BfWXS3FnlTvzEQq0yPrJ7nUOo%3D&reserved=0>
>
>
> First, it would make it easier for people to find, and second, it would
> also help a lot to see on that page how the algorithm compares to the
> others, to be able to choose it appropriately.
>
>
> Good point. Will do.
>
>
>
>
>
>
> Unrelated: @All/Maintainers: It seems like lots (all) of the images on the
> documentation website are broken? At least for me. E.g.:
>
>
>
>
>
>
>
> Best wishes,
>
> Patrik
>
>
>
> On Mon, 1 Jun 2020 at 17:59, Rasmus Munk Larsen <[email protected]>
> wrote:
>
> Hi Oleg and Sameer,
>
>
>
> A faster option than SVD, but more robust than QR (since it also handles
> the under-determined case) is the complete orthogonal decomposition that I
> implemented in Eigen a few years ago.
>
>
> https://eigen.tuxfamily.org/dox/classEigen_1_1CompleteOrthogonalDecomposition.html
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Feigen.tuxfamily.org%2Fdox%2FclassEigen_1_1CompleteOrthogonalDecomposition.html&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=4ALzcdxWY8wDOlejWGXr9DfIUg%2FGV%2B9CnWkoozLWMSU%3D&reserved=0>
>
> (Looks like the docstring is broken - oops!)
>
> It appears to also be available in the 3.3 branch:
> https://gitlab.com/libeigen/eigen/-/blob/3.3/Eigen/src/QR/CompleteOrthogonalDecomposition.h
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.com%2Flibeigen%2Feigen%2F-%2Fblob%2F3.3%2FEigen%2Fsrc%2FQR%2FCompleteOrthogonalDecomposition.h&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=F4uktFTL%2BeQ%2BOqeURPZ%2FoOaoReqnH1hU2CobNC%2BNxHk%3D&reserved=0>
>
> Rasmus
>
>
>
> On Mon, Jun 1, 2020 at 6:57 AM Sameer Agarwal <[email protected]>
> wrote:
>
> Oleg,
>
> Two ideas:
>
>
>
> 1. You may have an easier time using QR factorization instead of SVD to
> solve your least squares problem.
>
> 2.  But you can do better, instead of trying to solve linear least squares
> problem involving a matrix of Jets, you are better off, solving the linear
> least squares problem on the scalars, and then using the implicit
> function theorem
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FImplicit_function_theorem&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=wACe44wQ0vA%2BVFojAnCxvAnvRkgps4y2sIcl0d1wLC4%3D&reserved=0>
> to compute the derivative w.r.t the parameters and then applying the chain
> rule.
>
>
>
> i.e., start with min |A x = b|
>
>
>
> the solution satisfies the equation
>
>
>
> A'A x - A'b = 0.
>
>
>
> solve this equation to get the optimal value of x, and then compute the
> jacobian of this equation w.r.t A, b and x. and apply the implicit theorem.
>
>
>
> Sameer
>
>
>
>
>
> On Mon, Jun 1, 2020 at 4:46 AM Oleg Shirokobrod <
> [email protected]> wrote:
>
> Hi list, I am using Eigen 3.3.7 release with ceres solver 1.14.0 with
> autodiff Jet data type and I have some problems. I need to solve linear
> least square subproblem within variable projection algorithm, namely I need
> to solve LLS equation
>
> A(p)*x = b
>
> Where matrix A(p) depends on nonlinear parameters p:
>
> x(p) = pseudo-inverse(A(p))*b;
>
> x(p) will be optimized in nonlinear least squares fitting, so I need
> Jcobian. Rhs b is measured vector of doubles, e.g. VectorXd. In order to
> use ceres's autodiff p must be of Jet type. Ceres provides corresponding
> traits for binary operations
>
>
>
> #if EIGEN_VERSION_AT_LEAST(3, 3, 0)
> // Specifying the return type of binary operations between Jets and scalar
> types
> // allows you to perform matrix/array operations with Eigen matrices and
> arrays
> // such as addition, subtraction, multiplication, and division where one
> Eigen
> // matrix/array is of type Jet and the other is a scalar type. This
> improves
> // performance by using the optimized scalar-to-Jet binary operations but
> // is only available on Eigen versions >= 3.3
> template <typename BinaryOp, typename T, int N>
> struct ScalarBinaryOpTraits<ceres::Jet<T, N>, T, BinaryOp> {
>   typedef ceres::Jet<T, N> ReturnType;
> };
> template <typename BinaryOp, typename T, int N>
> struct ScalarBinaryOpTraits<T, ceres::Jet<T, N>, BinaryOp> {
>   typedef ceres::Jet<T, N> ReturnType;
> };
> #endif  // EIGEN_VERSION_AT_LEAST(3, 3, 0)
>
>
>
> There two problems.
>
> 1. Small problem. In a function "RealScalar threshold() const" in
> SCDbase.h I have to replace "return m_usePrescribedThreshold ?
> m_prescribedThreshold
>                                     : diagSize*
> NumTraits<Scalar>::epsilon();" with "return m_usePrescribedThreshold ?
> m_prescribedThreshold
>                                     : Scalar(diagSize)*
> NumTraits<Scalar>::epsilon();"
>
> This fix is similar Gael's fix of Bug 1403
> <https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Feigen.tuxfamily.org%2Fbz%2Fshow_bug.cgi%3Fid%3D1403&data=01%7C01%7Ctobias.wood%40kcl.ac.uk%7C9b7731b3d2c24c6ea7e908d808af4522%7C8370cf1416f34c16b83c724071654356%7C0&sdata=xcVjY1p2d8oscbHsEuiqRMdNPzGOGGI%2BLb%2FOqZUWrec%3D&reserved=0>
>
> 2. It is less trivial. I expect that x(p) = pseudo-inverse(A(p))*b; is
> vector of Jet. And it is actually true for e.g SVD decompoazition
>
> x(p) = VSU^T * b.
>
> But if I use
>
> JcobySVD<Matrix<Jet<double, 2>, Dynamic, Dynamic>> svd(A);
>
> x(p) = svd.solve(b),
>
> I got error message.
>
> Here code for reproducing the error
>
>
>
> // test_svd_jet.cpp
>
> #include <ceres/jet.h>
>
> using ceres::Jet;
>
>
>
> int test_svd_jet()
> {
>
>     typedef Matrix<Jet<double, 2>, Dynamic, Dynamic> Mat;
>     typedef Matrix<Jet<double, 2>, Dynamic, 1> Vec;
>      Mat A = MatrixXd::Random(3, 2).cast <Jet<double, 2>>();
>      VectorXd b = VectorXd::Random(3);
>
>      JacobiSVD<Mat> svd(A, ComputeThinU | ComputeThinV);
>      int l_rank = svd.rank();
>      Vec c = svd.matrixV().leftCols(l_rank)
>          * svd.singularValues().head(l_rank).asDiagonal().inverse()
>          * svd.matrixU().leftCols(l_rank).adjoint() * b; // *
>
>      Vec c1 = svd.solve(b.cast<Jet<double, 2>>()); // **
>
>      Vec c2 = svd.solve(b); // ***
>
>      return 0;
> }
>
> // End test_svd_jet.cpp
>
>
>
> // * and // ** work fine an give the same results. // *** fails with VS
> 2019 error message
>
> Eigen\src\Core\functors\AssignmentFunctors.h(24,1):
>
> error C2679: binary '=': no operator found which takes
> a right-hand operand of type 'const SrcScalar'
> (or there is no acceptable conversion)
>
> The error points to line //***. I thing that solution is of type VectorXd
> instead of Vec and there is problem with assignment of double to Jet.
> Derivatives are lost either. It should work similar to complex type. If A
> is complex matrix and b is real vector, x must be complex. There is
> something wrong with Type deduction in SVD or QR decomposition.
>
>
>
> Do you have any idea of how to fix it.
>
>
>
> Best regards,
>
>
>
> Oleg Shirokobrod
>
>
>
>

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