From 72f66d717d3312b1d02fde292919fc6214a51083 Mon Sep 17 00:00:00 2001 From: Jitse Niesen Date: Mon, 18 May 2009 23:14:53 +0100 Subject: Evaluate argument of matrix exponential only once. --- .../Eigen/src/MatrixFunctions/MatrixExponential.h | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h') diff --git a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h index bc1bcceb2..7950d22b4 100644 --- a/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h +++ b/unsupported/Eigen/src/MatrixFunctions/MatrixExponential.h @@ -72,7 +72,8 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri PlainMatrixType num, den, U, V; PlainMatrixType Id = PlainMatrixType::Identity(M.rows(), M.cols()); - RealScalar l1norm = M.cwise().abs().colwise().sum().maxCoeff(); + typename ei_eval::type Meval = M.eval(); + RealScalar l1norm = Meval.cwise().abs().colwise().sum().maxCoeff(); int squarings = 0; // Choose degree of Pade approximant, depending on norm of M @@ -81,9 +82,9 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri // Use (3,3)-Pade const Scalar b[] = {120., 60., 12., 1.}; PlainMatrixType M2; - M2 = (M * M).lazy(); + M2 = (Meval * Meval).lazy(); num = b[3]*M2 + b[1]*Id; - U = (M * num).lazy(); + U = (Meval * num).lazy(); V = b[2]*M2 + b[0]*Id; } else if (l1norm < 2.539398330063230e-001) { @@ -91,10 +92,10 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri // Use (5,5)-Pade const Scalar b[] = {30240., 15120., 3360., 420., 30., 1.}; PlainMatrixType M2, M4; - M2 = (M * M).lazy(); + M2 = (Meval * Meval).lazy(); M4 = (M2 * M2).lazy(); num = b[5]*M4 + b[3]*M2 + b[1]*Id; - U = (M * num).lazy(); + U = (Meval * num).lazy(); V = b[4]*M4 + b[2]*M2 + b[0]*Id; } else if (l1norm < 9.504178996162932e-001) { @@ -102,11 +103,11 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri // Use (7,7)-Pade const Scalar b[] = {17297280., 8648640., 1995840., 277200., 25200., 1512., 56., 1.}; PlainMatrixType M2, M4, M6; - M2 = (M * M).lazy(); + M2 = (Meval * Meval).lazy(); M4 = (M2 * M2).lazy(); M6 = (M4 * M2).lazy(); num = b[7]*M6 + b[5]*M4 + b[3]*M2 + b[1]*Id; - U = (M * num).lazy(); + U = (Meval * num).lazy(); V = b[6]*M6 + b[4]*M4 + b[2]*M2 + b[0]*Id; } else if (l1norm < 2.097847961257068e+000) { @@ -115,12 +116,12 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri const Scalar b[] = {17643225600., 8821612800., 2075673600., 302702400., 30270240., 2162160., 110880., 3960., 90., 1.}; PlainMatrixType M2, M4, M6, M8; - M2 = (M * M).lazy(); + M2 = (Meval * Meval).lazy(); M4 = (M2 * M2).lazy(); M6 = (M4 * M2).lazy(); M8 = (M6 * M2).lazy(); num = b[9]*M8 + b[7]*M6 + b[5]*M4 + b[3]*M2 + b[1]*Id; - U = (M * num).lazy(); + U = (Meval * num).lazy(); V = b[8]*M8 + b[6]*M6 + b[4]*M4 + b[2]*M2 + b[0]*Id; } else { @@ -135,7 +136,7 @@ void ei_matrix_exponential(const MatrixBase &M, typename ei_plain_matri squarings = std::max(0, (int)ceil(log2(l1norm / maxnorm))); PlainMatrixType A, A2, A4, A6; - A = M / pow(Scalar(2), squarings); + A = Meval / pow(Scalar(2), squarings); A2 = (A * A).lazy(); A4 = (A2 * A2).lazy(); A6 = (A4 * A2).lazy(); -- cgit v1.2.3