| // Ceres Solver - A fast non-linear least squares minimizer | 
 | // Copyright 2015 Google Inc. All rights reserved. | 
 | // http://ceres-solver.org/ | 
 | // | 
 | // Redistribution and use in source and binary forms, with or without | 
 | // modification, are permitted provided that the following conditions are met: | 
 | // | 
 | // * Redistributions of source code must retain the above copyright notice, | 
 | //   this list of conditions and the following disclaimer. | 
 | // * Redistributions in binary form must reproduce the above copyright notice, | 
 | //   this list of conditions and the following disclaimer in the documentation | 
 | //   and/or other materials provided with the distribution. | 
 | // * Neither the name of Google Inc. nor the names of its contributors may be | 
 | //   used to endorse or promote products derived from this software without | 
 | //   specific prior written permission. | 
 | // | 
 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | 
 | // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 
 | // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | 
 | // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | 
 | // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | 
 | // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | 
 | // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | 
 | // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | 
 | // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | 
 | // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | 
 | // POSSIBILITY OF SUCH DAMAGE. | 
 | // | 
 | // Author: sameeragarwal@google.com (Sameer Agarwal) | 
 | // | 
 | // Simple blas functions for use in the Schur Eliminator. These are | 
 | // fairly basic implementations which already yield a significant | 
 | // speedup in the eliminator performance. | 
 |  | 
 | #ifndef CERES_INTERNAL_SMALL_BLAS_H_ | 
 | #define CERES_INTERNAL_SMALL_BLAS_H_ | 
 |  | 
 | #include "ceres/internal/eigen.h" | 
 | #include "ceres/internal/export.h" | 
 | #include "glog/logging.h" | 
 | #include "small_blas_generic.h" | 
 |  | 
 | namespace ceres { | 
 | namespace internal { | 
 |  | 
 | // The following three macros are used to share code and reduce | 
 | // template junk across the various GEMM variants. | 
 | #define CERES_GEMM_BEGIN(name)                                          \ | 
 |   template <int kRowA, int kColA, int kRowB, int kColB, int kOperation> \ | 
 |   inline void name(const double* A,                                     \ | 
 |                    const int num_row_a,                                 \ | 
 |                    const int num_col_a,                                 \ | 
 |                    const double* B,                                     \ | 
 |                    const int num_row_b,                                 \ | 
 |                    const int num_col_b,                                 \ | 
 |                    double* C,                                           \ | 
 |                    const int start_row_c,                               \ | 
 |                    const int start_col_c,                               \ | 
 |                    const int row_stride_c,                              \ | 
 |                    const int col_stride_c) | 
 |  | 
 | #define CERES_GEMM_NAIVE_HEADER                                        \ | 
 |   DCHECK_GT(num_row_a, 0);                                             \ | 
 |   DCHECK_GT(num_col_a, 0);                                             \ | 
 |   DCHECK_GT(num_row_b, 0);                                             \ | 
 |   DCHECK_GT(num_col_b, 0);                                             \ | 
 |   DCHECK_GE(start_row_c, 0);                                           \ | 
 |   DCHECK_GE(start_col_c, 0);                                           \ | 
 |   DCHECK_GT(row_stride_c, 0);                                          \ | 
 |   DCHECK_GT(col_stride_c, 0);                                          \ | 
 |   DCHECK((kRowA == Eigen::Dynamic) || (kRowA == num_row_a));           \ | 
 |   DCHECK((kColA == Eigen::Dynamic) || (kColA == num_col_a));           \ | 
 |   DCHECK((kRowB == Eigen::Dynamic) || (kRowB == num_row_b));           \ | 
 |   DCHECK((kColB == Eigen::Dynamic) || (kColB == num_col_b));           \ | 
 |   const int NUM_ROW_A = (kRowA != Eigen::Dynamic ? kRowA : num_row_a); \ | 
 |   const int NUM_COL_A = (kColA != Eigen::Dynamic ? kColA : num_col_a); \ | 
 |   const int NUM_ROW_B = (kRowB != Eigen::Dynamic ? kRowB : num_row_b); \ | 
 |   const int NUM_COL_B = (kColB != Eigen::Dynamic ? kColB : num_col_b); | 
 |  | 
 | #define CERES_GEMM_EIGEN_HEADER                                 \ | 
 |   const typename EigenTypes<kRowA, kColA>::ConstMatrixRef Aref( \ | 
 |       A, num_row_a, num_col_a);                                 \ | 
 |   const typename EigenTypes<kRowB, kColB>::ConstMatrixRef Bref( \ | 
 |       B, num_row_b, num_col_b);                                 \ | 
 |   MatrixRef Cref(C, row_stride_c, col_stride_c); | 
 |  | 
 | // clang-format off | 
 | #define CERES_CALL_GEMM(name)                                           \ | 
 |   name<kRowA, kColA, kRowB, kColB, kOperation>(                         \ | 
 |       A, num_row_a, num_col_a,                                          \ | 
 |       B, num_row_b, num_col_b,                                          \ | 
 |       C, start_row_c, start_col_c, row_stride_c, col_stride_c); | 
 | // clang-format on | 
 |  | 
 | #define CERES_GEMM_STORE_SINGLE(p, index, value) \ | 
 |   if (kOperation > 0) {                          \ | 
 |     p[index] += value;                           \ | 
 |   } else if (kOperation < 0) {                   \ | 
 |     p[index] -= value;                           \ | 
 |   } else {                                       \ | 
 |     p[index] = value;                            \ | 
 |   } | 
 |  | 
 | #define CERES_GEMM_STORE_PAIR(p, index, v1, v2) \ | 
 |   if (kOperation > 0) {                         \ | 
 |     p[index] += v1;                             \ | 
 |     p[index + 1] += v2;                         \ | 
 |   } else if (kOperation < 0) {                  \ | 
 |     p[index] -= v1;                             \ | 
 |     p[index + 1] -= v2;                         \ | 
 |   } else {                                      \ | 
 |     p[index] = v1;                              \ | 
 |     p[index + 1] = v2;                          \ | 
 |   } | 
 |  | 
 | // For the matrix-matrix functions below, there are three variants for | 
 | // each functionality. Foo, FooNaive and FooEigen. Foo is the one to | 
 | // be called by the user. FooNaive is a basic loop based | 
 | // implementation and FooEigen uses Eigen's implementation. Foo | 
 | // chooses between FooNaive and FooEigen depending on how many of the | 
 | // template arguments are fixed at compile time. Currently, FooEigen | 
 | // is called if all matrix dimensions are compile time | 
 | // constants. FooNaive is called otherwise. This leads to the best | 
 | // performance currently. | 
 | // | 
 | // The MatrixMatrixMultiply variants compute: | 
 | // | 
 | //   C op A * B; | 
 | // | 
 | // The MatrixTransposeMatrixMultiply variants compute: | 
 | // | 
 | //   C op A' * B | 
 | // | 
 | // where op can be +=, -=, or =. | 
 | // | 
 | // The template parameters (kRowA, kColA, kRowB, kColB) allow | 
 | // specialization of the loop at compile time. If this information is | 
 | // not available, then Eigen::Dynamic should be used as the template | 
 | // argument. | 
 | // | 
 | //   kOperation =  1  -> C += A * B | 
 | //   kOperation = -1  -> C -= A * B | 
 | //   kOperation =  0  -> C  = A * B | 
 | // | 
 | // The functions can write into matrices C which are larger than the | 
 | // matrix A * B. This is done by specifying the true size of C via | 
 | // row_stride_c and col_stride_c, and then indicating where A * B | 
 | // should be written into by start_row_c and start_col_c. | 
 | // | 
 | // Graphically if row_stride_c = 10, col_stride_c = 12, start_row_c = | 
 | // 4 and start_col_c = 5, then if A = 3x2 and B = 2x4, we get | 
 | // | 
 | //   ------------ | 
 | //   ------------ | 
 | //   ------------ | 
 | //   ------------ | 
 | //   -----xxxx--- | 
 | //   -----xxxx--- | 
 | //   -----xxxx--- | 
 | //   ------------ | 
 | //   ------------ | 
 | //   ------------ | 
 | // | 
 | CERES_GEMM_BEGIN(MatrixMatrixMultiplyEigen) { | 
 |   CERES_GEMM_EIGEN_HEADER | 
 |   Eigen::Block<MatrixRef, kRowA, kColB> block( | 
 |       Cref, start_row_c, start_col_c, num_row_a, num_col_b); | 
 |  | 
 |   if (kOperation > 0) { | 
 |     block.noalias() += Aref * Bref; | 
 |   } else if (kOperation < 0) { | 
 |     block.noalias() -= Aref * Bref; | 
 |   } else { | 
 |     block.noalias() = Aref * Bref; | 
 |   } | 
 | } | 
 |  | 
 | CERES_GEMM_BEGIN(MatrixMatrixMultiplyNaive) { | 
 |   CERES_GEMM_NAIVE_HEADER | 
 |   DCHECK_EQ(NUM_COL_A, NUM_ROW_B); | 
 |  | 
 |   const int NUM_ROW_C = NUM_ROW_A; | 
 |   const int NUM_COL_C = NUM_COL_B; | 
 |   DCHECK_LE(start_row_c + NUM_ROW_C, row_stride_c); | 
 |   DCHECK_LE(start_col_c + NUM_COL_C, col_stride_c); | 
 |   const int span = 4; | 
 |  | 
 |   // Calculate the remainder part first. | 
 |  | 
 |   // Process the last odd column if present. | 
 |   if (NUM_COL_C & 1) { | 
 |     int col = NUM_COL_C - 1; | 
 |     const double* pa = &A[0]; | 
 |     for (int row = 0; row < NUM_ROW_C; ++row, pa += NUM_COL_A) { | 
 |       const double* pb = &B[col]; | 
 |       double tmp = 0.0; | 
 |       for (int k = 0; k < NUM_COL_A; ++k, pb += NUM_COL_B) { | 
 |         tmp += pa[k] * pb[0]; | 
 |       } | 
 |  | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       CERES_GEMM_STORE_SINGLE(C, index, tmp); | 
 |     } | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_C == 1) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Process the couple columns in remainder if present. | 
 |   if (NUM_COL_C & 2) { | 
 |     int col = NUM_COL_C & (~(span - 1)); | 
 |     const double* pa = &A[0]; | 
 |     for (int row = 0; row < NUM_ROW_C; ++row, pa += NUM_COL_A) { | 
 |       const double* pb = &B[col]; | 
 |       double tmp1 = 0.0, tmp2 = 0.0; | 
 |       for (int k = 0; k < NUM_COL_A; ++k, pb += NUM_COL_B) { | 
 |         double av = pa[k]; | 
 |         tmp1 += av * pb[0]; | 
 |         tmp2 += av * pb[1]; | 
 |       } | 
 |  | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       CERES_GEMM_STORE_PAIR(C, index, tmp1, tmp2); | 
 |     } | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_C < span) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Calculate the main part with multiples of 4. | 
 |   int col_m = NUM_COL_C & (~(span - 1)); | 
 |   for (int col = 0; col < col_m; col += span) { | 
 |     for (int row = 0; row < NUM_ROW_C; ++row) { | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       // clang-format off | 
 |       MMM_mat1x4(NUM_COL_A, &A[row * NUM_COL_A], | 
 |                  &B[col], NUM_COL_B, &C[index], kOperation); | 
 |       // clang-format on | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | CERES_GEMM_BEGIN(MatrixMatrixMultiply) { | 
 | #ifdef CERES_NO_CUSTOM_BLAS | 
 |  | 
 |   CERES_CALL_GEMM(MatrixMatrixMultiplyEigen) | 
 |   return; | 
 |  | 
 | #else | 
 |  | 
 |   if (kRowA != Eigen::Dynamic && kColA != Eigen::Dynamic && | 
 |       kRowB != Eigen::Dynamic && kColB != Eigen::Dynamic) { | 
 |     CERES_CALL_GEMM(MatrixMatrixMultiplyEigen) | 
 |   } else { | 
 |     CERES_CALL_GEMM(MatrixMatrixMultiplyNaive) | 
 |   } | 
 |  | 
 | #endif | 
 | } | 
 |  | 
 | CERES_GEMM_BEGIN(MatrixTransposeMatrixMultiplyEigen) { | 
 |   CERES_GEMM_EIGEN_HEADER | 
 |   // clang-format off | 
 |   Eigen::Block<MatrixRef, kColA, kColB> block(Cref, | 
 |                                               start_row_c, start_col_c, | 
 |                                               num_col_a, num_col_b); | 
 |   // clang-format on | 
 |   if (kOperation > 0) { | 
 |     block.noalias() += Aref.transpose() * Bref; | 
 |   } else if (kOperation < 0) { | 
 |     block.noalias() -= Aref.transpose() * Bref; | 
 |   } else { | 
 |     block.noalias() = Aref.transpose() * Bref; | 
 |   } | 
 | } | 
 |  | 
 | CERES_GEMM_BEGIN(MatrixTransposeMatrixMultiplyNaive) { | 
 |   CERES_GEMM_NAIVE_HEADER | 
 |   DCHECK_EQ(NUM_ROW_A, NUM_ROW_B); | 
 |  | 
 |   const int NUM_ROW_C = NUM_COL_A; | 
 |   const int NUM_COL_C = NUM_COL_B; | 
 |   DCHECK_LE(start_row_c + NUM_ROW_C, row_stride_c); | 
 |   DCHECK_LE(start_col_c + NUM_COL_C, col_stride_c); | 
 |   const int span = 4; | 
 |  | 
 |   // Process the remainder part first. | 
 |  | 
 |   // Process the last odd column if present. | 
 |   if (NUM_COL_C & 1) { | 
 |     int col = NUM_COL_C - 1; | 
 |     for (int row = 0; row < NUM_ROW_C; ++row) { | 
 |       const double* pa = &A[row]; | 
 |       const double* pb = &B[col]; | 
 |       double tmp = 0.0; | 
 |       for (int k = 0; k < NUM_ROW_A; ++k) { | 
 |         tmp += pa[0] * pb[0]; | 
 |         pa += NUM_COL_A; | 
 |         pb += NUM_COL_B; | 
 |       } | 
 |  | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       CERES_GEMM_STORE_SINGLE(C, index, tmp); | 
 |     } | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_C == 1) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Process the couple columns in remainder if present. | 
 |   if (NUM_COL_C & 2) { | 
 |     int col = NUM_COL_C & (~(span - 1)); | 
 |     for (int row = 0; row < NUM_ROW_C; ++row) { | 
 |       const double* pa = &A[row]; | 
 |       const double* pb = &B[col]; | 
 |       double tmp1 = 0.0, tmp2 = 0.0; | 
 |       for (int k = 0; k < NUM_ROW_A; ++k) { | 
 |         double av = *pa; | 
 |         tmp1 += av * pb[0]; | 
 |         tmp2 += av * pb[1]; | 
 |         pa += NUM_COL_A; | 
 |         pb += NUM_COL_B; | 
 |       } | 
 |  | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       CERES_GEMM_STORE_PAIR(C, index, tmp1, tmp2); | 
 |     } | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_C < span) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Process the main part with multiples of 4. | 
 |   int col_m = NUM_COL_C & (~(span - 1)); | 
 |   for (int col = 0; col < col_m; col += span) { | 
 |     for (int row = 0; row < NUM_ROW_C; ++row) { | 
 |       const int index = (row + start_row_c) * col_stride_c + start_col_c + col; | 
 |       // clang-format off | 
 |       MTM_mat1x4(NUM_ROW_A, &A[row], NUM_COL_A, | 
 |                  &B[col], NUM_COL_B, &C[index], kOperation); | 
 |       // clang-format on | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | CERES_GEMM_BEGIN(MatrixTransposeMatrixMultiply) { | 
 | #ifdef CERES_NO_CUSTOM_BLAS | 
 |  | 
 |   CERES_CALL_GEMM(MatrixTransposeMatrixMultiplyEigen) | 
 |   return; | 
 |  | 
 | #else | 
 |  | 
 |   if (kRowA != Eigen::Dynamic && kColA != Eigen::Dynamic && | 
 |       kRowB != Eigen::Dynamic && kColB != Eigen::Dynamic) { | 
 |     CERES_CALL_GEMM(MatrixTransposeMatrixMultiplyEigen) | 
 |   } else { | 
 |     CERES_CALL_GEMM(MatrixTransposeMatrixMultiplyNaive) | 
 |   } | 
 |  | 
 | #endif | 
 | } | 
 |  | 
 | // Matrix-Vector multiplication | 
 | // | 
 | // c op A * b; | 
 | // | 
 | // where op can be +=, -=, or =. | 
 | // | 
 | // The template parameters (kRowA, kColA) allow specialization of the | 
 | // loop at compile time. If this information is not available, then | 
 | // Eigen::Dynamic should be used as the template argument. | 
 | // | 
 | // kOperation =  1  -> c += A' * b | 
 | // kOperation = -1  -> c -= A' * b | 
 | // kOperation =  0  -> c  = A' * b | 
 | template <int kRowA, int kColA, int kOperation> | 
 | inline void MatrixVectorMultiply(const double* A, | 
 |                                  const int num_row_a, | 
 |                                  const int num_col_a, | 
 |                                  const double* b, | 
 |                                  double* c) { | 
 | #ifdef CERES_NO_CUSTOM_BLAS | 
 |   const typename EigenTypes<kRowA, kColA>::ConstMatrixRef Aref( | 
 |       A, num_row_a, num_col_a); | 
 |   const typename EigenTypes<kColA>::ConstVectorRef bref(b, num_col_a); | 
 |   typename EigenTypes<kRowA>::VectorRef cref(c, num_row_a); | 
 |  | 
 |   // lazyProduct works better than .noalias() for matrix-vector | 
 |   // products. | 
 |   if (kOperation > 0) { | 
 |     cref += Aref.lazyProduct(bref); | 
 |   } else if (kOperation < 0) { | 
 |     cref -= Aref.lazyProduct(bref); | 
 |   } else { | 
 |     cref = Aref.lazyProduct(bref); | 
 |   } | 
 | #else | 
 |  | 
 |   DCHECK_GT(num_row_a, 0); | 
 |   DCHECK_GT(num_col_a, 0); | 
 |   DCHECK((kRowA == Eigen::Dynamic) || (kRowA == num_row_a)); | 
 |   DCHECK((kColA == Eigen::Dynamic) || (kColA == num_col_a)); | 
 |  | 
 |   const int NUM_ROW_A = (kRowA != Eigen::Dynamic ? kRowA : num_row_a); | 
 |   const int NUM_COL_A = (kColA != Eigen::Dynamic ? kColA : num_col_a); | 
 |   const int span = 4; | 
 |  | 
 |   // Calculate the remainder part first. | 
 |  | 
 |   // Process the last odd row if present. | 
 |   if (NUM_ROW_A & 1) { | 
 |     int row = NUM_ROW_A - 1; | 
 |     const double* pa = &A[row * NUM_COL_A]; | 
 |     const double* pb = &b[0]; | 
 |     double tmp = 0.0; | 
 |     for (int col = 0; col < NUM_COL_A; ++col) { | 
 |       tmp += (*pa++) * (*pb++); | 
 |     } | 
 |     CERES_GEMM_STORE_SINGLE(c, row, tmp); | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_ROW_A == 1) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Process the couple rows in remainder if present. | 
 |   if (NUM_ROW_A & 2) { | 
 |     int row = NUM_ROW_A & (~(span - 1)); | 
 |     const double* pa1 = &A[row * NUM_COL_A]; | 
 |     const double* pa2 = pa1 + NUM_COL_A; | 
 |     const double* pb = &b[0]; | 
 |     double tmp1 = 0.0, tmp2 = 0.0; | 
 |     for (int col = 0; col < NUM_COL_A; ++col) { | 
 |       double bv = *pb++; | 
 |       tmp1 += *(pa1++) * bv; | 
 |       tmp2 += *(pa2++) * bv; | 
 |     } | 
 |     CERES_GEMM_STORE_PAIR(c, row, tmp1, tmp2); | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_ROW_A < span) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Calculate the main part with multiples of 4. | 
 |   int row_m = NUM_ROW_A & (~(span - 1)); | 
 |   for (int row = 0; row < row_m; row += span) { | 
 |     // clang-format off | 
 |     MVM_mat4x1(NUM_COL_A, &A[row * NUM_COL_A], NUM_COL_A, | 
 |                &b[0], &c[row], kOperation); | 
 |     // clang-format on | 
 |   } | 
 |  | 
 | #endif  // CERES_NO_CUSTOM_BLAS | 
 | } | 
 |  | 
 | // Similar to MatrixVectorMultiply, except that A is transposed, i.e., | 
 | // | 
 | // c op A' * b; | 
 | template <int kRowA, int kColA, int kOperation> | 
 | inline void MatrixTransposeVectorMultiply(const double* A, | 
 |                                           const int num_row_a, | 
 |                                           const int num_col_a, | 
 |                                           const double* b, | 
 |                                           double* c) { | 
 | #ifdef CERES_NO_CUSTOM_BLAS | 
 |   const typename EigenTypes<kRowA, kColA>::ConstMatrixRef Aref( | 
 |       A, num_row_a, num_col_a); | 
 |   const typename EigenTypes<kRowA>::ConstVectorRef bref(b, num_row_a); | 
 |   typename EigenTypes<kColA>::VectorRef cref(c, num_col_a); | 
 |  | 
 |   // lazyProduct works better than .noalias() for matrix-vector | 
 |   // products. | 
 |   if (kOperation > 0) { | 
 |     cref += Aref.transpose().lazyProduct(bref); | 
 |   } else if (kOperation < 0) { | 
 |     cref -= Aref.transpose().lazyProduct(bref); | 
 |   } else { | 
 |     cref = Aref.transpose().lazyProduct(bref); | 
 |   } | 
 | #else | 
 |  | 
 |   DCHECK_GT(num_row_a, 0); | 
 |   DCHECK_GT(num_col_a, 0); | 
 |   DCHECK((kRowA == Eigen::Dynamic) || (kRowA == num_row_a)); | 
 |   DCHECK((kColA == Eigen::Dynamic) || (kColA == num_col_a)); | 
 |  | 
 |   const int NUM_ROW_A = (kRowA != Eigen::Dynamic ? kRowA : num_row_a); | 
 |   const int NUM_COL_A = (kColA != Eigen::Dynamic ? kColA : num_col_a); | 
 |   const int span = 4; | 
 |  | 
 |   // Calculate the remainder part first. | 
 |  | 
 |   // Process the last odd column if present. | 
 |   if (NUM_COL_A & 1) { | 
 |     int row = NUM_COL_A - 1; | 
 |     const double* pa = &A[row]; | 
 |     const double* pb = &b[0]; | 
 |     double tmp = 0.0; | 
 |     for (int col = 0; col < NUM_ROW_A; ++col) { | 
 |       tmp += *pa * (*pb++); | 
 |       pa += NUM_COL_A; | 
 |     } | 
 |     CERES_GEMM_STORE_SINGLE(c, row, tmp); | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_A == 1) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Process the couple columns in remainder if present. | 
 |   if (NUM_COL_A & 2) { | 
 |     int row = NUM_COL_A & (~(span - 1)); | 
 |     const double* pa = &A[row]; | 
 |     const double* pb = &b[0]; | 
 |     double tmp1 = 0.0, tmp2 = 0.0; | 
 |     for (int col = 0; col < NUM_ROW_A; ++col) { | 
 |       // clang-format off | 
 |       double bv = *pb++; | 
 |       tmp1 += *(pa    ) * bv; | 
 |       tmp2 += *(pa + 1) * bv; | 
 |       pa += NUM_COL_A; | 
 |       // clang-format on | 
 |     } | 
 |     CERES_GEMM_STORE_PAIR(c, row, tmp1, tmp2); | 
 |  | 
 |     // Return directly for efficiency of extremely small matrix multiply. | 
 |     if (NUM_COL_A < span) { | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   // Calculate the main part with multiples of 4. | 
 |   int row_m = NUM_COL_A & (~(span - 1)); | 
 |   for (int row = 0; row < row_m; row += span) { | 
 |     // clang-format off | 
 |     MTV_mat4x1(NUM_ROW_A, &A[row], NUM_COL_A, | 
 |                &b[0], &c[row], kOperation); | 
 |     // clang-format on | 
 |   } | 
 |  | 
 | #endif  // CERES_NO_CUSTOM_BLAS | 
 | } | 
 |  | 
 | #undef CERES_GEMM_BEGIN | 
 | #undef CERES_GEMM_EIGEN_HEADER | 
 | #undef CERES_GEMM_NAIVE_HEADER | 
 | #undef CERES_CALL_GEMM | 
 | #undef CERES_GEMM_STORE_SINGLE | 
 | #undef CERES_GEMM_STORE_PAIR | 
 |  | 
 | }  // namespace internal | 
 | }  // namespace ceres | 
 |  | 
 | #endif  // CERES_INTERNAL_SMALL_BLAS_H_ |