* Woodburry 3x3 kernel fixed

* Written Unified Sherman-Morrison-Woodbury kernel that partitions
  the updates in blocks of 3 and tries them with Woodbury 3x3.
  The remainder of 2 or one are attempted with Woodbury 2x2 and SM2.

For now the unified kernel gives fails where pure SM2 does not.
I suspect there is something going wrong in how the updates are partitioned.

include/Helpers.hpp

@@ -75,26 +75,6 @@ void showMatrix2(T *matrix, unsigned int M, unsigned int N, std::string name) {
   std::cout << std::endl;
 }
 
-
-template <typename T>
-void showMatrixNS(T *matrix, unsigned int M, unsigned int N, std::string name) {
-  std::cout.precision(17);
-  std::cout << name << " = [" << std::endl;
-  for (unsigned int i = 0; i < M; i++) {
-    std::cout << "[";
-    for (unsigned int j = 0; j < N; j++) {
-      if (matrix[i * N + j] >= 0) {
-        std::cout << "  " << matrix[i * N + j] << ",";
-      } else {
-        std::cout << " " << matrix[i * N + j] << ",";
-      }
-    }
-    std::cout << " ]," << std::endl;
-  }
-  std::cout << "]" << std::endl;
-  std::cout << std::endl;
-}
-
 template <typename T> T *transpose(T *A, unsigned int M) {
   T *B = new T[M * M];
   for (unsigned int i = 0; i < M; i++) {

src/SMWB.cpp

@@ -8,13 +8,60 @@
 void SMWB1(double *Slater_inv, unsigned int Dim, unsigned int N_updates, double *Updates, unsigned int *Updates_index) {
            std::cerr << "Called Sherman-Morrison-Woodbury kernel 1 with " << N_updates << " updates" << std::endl;
 
-           bool ok;
+  unsigned int n_of_3blocks = N_updates / 3;
-           ok = WB2(Slater_inv, Dim, Updates, Updates_index);
+  unsigned int remainder = N_updates % 3;
-           if (!ok) {
+  unsigned int length_3block = 3 * Dim;
-             std::cerr << "Woodbury kernel failed!" << std::endl;
+  unsigned int length_2block = 2 * Dim;
-             SM2(Slater_inv, Dim, N_updates, Updates, Updates_index);
+  unsigned int length_1block = 1 * Dim;
-           }
+
-         }
+  // std::cerr << "Number of blocks: " << n_of_3blocks << ". Remainder: " << remainder << "." << std::endl;
+
+  // Apply first 3*n_of_3blocks updates in n_of_3blocks blocks of 3 updates with Woodbury 3x3 kernel
+  if (n_of_3blocks > 0) {
+    for (unsigned int i = 0; i < n_of_3blocks; i++) {
+      double Updates_3block[length_3block];
+      unsigned int Updates_index_3block[3];
+      Updates_index_3block[0] = Updates_index[3 * i + 0];
+      Updates_index_3block[1] = Updates_index[3 * i + 1];
+      Updates_index_3block[2] = Updates_index[3 * i + 2];
+      for (unsigned int j = 0; j < length_3block; j++) {
+        Updates_3block[j] = Updates[i * length_3block + j];
+      }
+      bool ok;
+      ok = WB3(Slater_inv, Dim, Updates_3block, Updates_index_3block);
+      if (!ok) { // Send the entire block to SM2
+        std::cerr << "Woodbury 3x3 kernel failed! Sending block to SM2" << std::endl;
+        SM2(Slater_inv, Dim, 3, Updates_3block, Updates_index_3block);
+      }
+    }
+  }
+
+  if (remainder == 2) { // Apply last remaining block of 2 updates with Woodbury 2x2 kernel
+    double Updates_2block[length_2block];
+    unsigned int Updates_index_2block[2];
+    Updates_index_2block[0] = Updates_index[3 * n_of_3blocks + 0];
+    Updates_index_2block[1] = Updates_index[3 * n_of_3blocks + 1];
+    for (unsigned int i = 0; i < length_2block; i++) {
+      Updates_2block[i] = Updates[n_of_3blocks * length_3block + i];
+    }
+    bool ok;
+    ok = WB2(Slater_inv, Dim, Updates_2block, Updates_index_2block);
+    if (!ok) { // Send the entire block to SM2
+      std::cerr << "Woodbury 2x2 kernel failed! Sending block to SM2" << std::endl;
+      SM2(Slater_inv, Dim, 2, Updates_2block, Updates_index_2block);
+    }
+  } else if (remainder == 1) { // Apply last remaining update with SM2
+    double Updates_1block[length_1block];
+    unsigned int Updates_index_1block[1];
+    Updates_index_1block[0] = Updates_index[3 * n_of_3blocks + 0];
+    for (unsigned int i = 0; i < length_1block; i++) {
+      Updates_1block[i] = Updates[n_of_3blocks * length_3block + i];
+    }
+    SM2(Slater_inv, Dim, 1, Updates_1block, Updates_index_1block);
+  } else { // remainder == 0
+    // Nothing left to do.
+  }
+}
 
 extern "C" {
 void SMWB1_f(double **linSlater_inv, unsigned int *Dim, unsigned int *N_updates,

src/Woodbury.cpp

@@ -2,21 +2,22 @@
     Woodbury 2x2 and 3x3 kernels
 
     Woodbury matrix identity:
-
     (S + U V)^{-1}  =  S^{-1} - C B^{-1} D
 
-    C := S^{-1} U,    dim x 2
+    All matrices are stored in row-major order
-    B := 1 + V C,     2 x 2
+*/
-    D := V S^{-1},    2 x dim
-
-    All matrices are stored in row-major order */
 
 #include "Woodbury.hpp"
 #include "Helpers.hpp"
 
-// Woodbury 2x2 kernel:
+// Woodbury 2x2 kernel
 bool WB2(double *Slater_inv, unsigned int Dim, double *Updates,
          unsigned int *Updates_index) {
+  /*
+      C := S^{-1} * U,    dim x 2
+      B := 1 + V * C,     2 x 2
+      D := V * S^{-1},    2 x dim
+  */
   std::cerr << "Called Woodbury 2x2 kernel" << std::endl;
 
   // Construct V from Updates_index
@@ -25,23 +26,23 @@ bool WB2(double *Slater_inv, unsigned int Dim, double *Updates,
   V[Updates_index[0] - 1] = 1;
   V[Dim + Updates_index[1] - 1] = 1;
 
-  // Compute C = S_inv U  !! NON-STANDARD MATRIX MULTIPLICATION BECAUSE 
+  // Compute C = S_inv * U  !! NON-STANDARD MATRIX MULTIPLICATION BECAUSE 
   // OF LAYOUT OF 'Updates' !!
   double C[2 * Dim];
   for(unsigned int i = 0; i < Dim; i++) {
     for(unsigned int j = 0; j < 2; j++) {
       C[i * 2 + j] = 0;
       for(unsigned int k = 0; k < Dim; k++) {
-        C[i * 2 + j] += Slater_inv[i * Dim + k] * Updates[4 * j + k];
+        C[i * 2 + j] += Slater_inv[i * Dim + k] * Updates[Dim * j + k];
       }
     }
   }
 
-  // Compute D = V x S^{-1}
+  // Compute D = V * S^{-1}
   double D[2 * Dim];
   matMul2(V, Slater_inv, D, 2, Dim, Dim);
 
-  // Compute B = 1 + V C
+  // Compute B = 1 + V * C
   double B[4];
   matMul2(V, C, B, 2, Dim, 2);
   B[0] += 1;
@@ -56,9 +57,9 @@ bool WB2(double *Slater_inv, unsigned int Dim, double *Updates,
   Binv[3] = idet * B[0];
 
   // Check if determinant of inverted matrix is not zero
-  double det = B[0] * B[3] - B[1] * B[2];
+  double det = Binv[0] * Binv[3] - Binv[1] * Binv[2];
   if (std::fabs(det) < threshold()) {
-    std::cerr << "Determinant approached 0!" << std::endl;
+    std::cerr << "Determinant approaching 0!" << std::endl;
     return false;
   }
 
@@ -79,60 +80,130 @@ bool WB2(double *Slater_inv, unsigned int Dim, double *Updates,
 }
 
 // Woodbury 3x3 kernel
-bool WB3(double *Slater_inv, unsigned int Dim, double *Updates,
+bool  WB3(double *Slater_inv, unsigned int Dim, double *Updates,
          unsigned int *Updates_index) {
+  /*
+      C := S^{-1} * U,    dim x 3
+      B := 1 + V * C,     3 x 3
+      D := V * S^{-1},    3 x dim
+  */
   std::cerr << "Called Woodbury 3x3 kernel" << std::endl;
 
+#ifdef DEBUG
+  showMatrix2(Slater_inv, Dim, Dim, "Slater_inv BEFORE update");
+  showMatrix2(Updates, 3, Dim, "Updates");
+  showMatrix2(Updates_index, 1, 3, "Updates_index");
+#endif
+
   // Construct V from Updates_index
-  unsigned int V[3 * Dim]; // 2 x Dim matrix stored in row-major order
+  unsigned int V[3 * Dim]; // 3 x Dim matrix stored in row-major order
+  std::memset(V, 0, 3 * Dim * sizeof(unsigned int));
   V[Updates_index[0] - 1] = 1;
   V[Dim + Updates_index[1] - 1] = 1;
   V[2 * Dim + Updates_index[2] - 1] = 1;
 
-  // Compute C
+#ifdef DEBUG
+  showMatrix2(V, 3, Dim, "V");
+#endif
+
+  // Compute C = S_inv * U  !! NON-STANDARD MATRIX MULTIPLICATION BECAUSE 
+  // OF LAYOUT OF 'Updates' !!
   double C[3 * Dim];
-  matMul2(Slater_inv, Updates, C, Dim, Dim, 3);
+  for(unsigned int i = 0; i < Dim; i++) {
-  // Compute B
+    for(unsigned int j = 0; j < 3; j++) {
+      C[i * 3 + j] = 0;
+      for(unsigned int k = 0; k < Dim; k++) {
+        C[i * 3 + j] += Slater_inv[i * Dim + k] * Updates[Dim * j + k];
+      }
+    }
+  }
+
+#ifdef DEBUG
+  showMatrix2(C, Dim, 3, "C = S_inv * U");
+#endif
+  // Compute D = V * S^{-1}
+  double D[3 * Dim];
+  matMul2(V, Slater_inv, D, 3, Dim, Dim);
+
+#ifdef DEBUG
+  showMatrix2(D, 3, Dim, "D = V * S_inv");
+#endif
+
+  // Compute B = 1 + V * C
   double B[9];
   matMul2(V, C, B, 3, Dim, 3);
-  // Compute 1 + B
   B[0] += 1;
   B[4] += 1;
   B[8] += 1;
 
-  double Binv[9];
+#ifdef DEBUG
-  Binv[0] = B[4] * B[8] - B[5] * B[7];
+  showMatrix2(B, 3, 3, "B = 1 + V * C");
-  Binv[3] = B[5] * B[6] - B[3] * B[8];
+#endif
-  Binv[6] = B[3] * B[7] - B[4] * B[6];
 
-  Binv[1] = B[2] * B[7] - B[1] * B[8];
+  // Compute B^{-1} with explicit formula for 3x3 inversion
-  Binv[4] = B[0] * B[8] - B[2] * B[6];
+  double Binv[9], det, idet;
-  Binv[7] = B[1] * B[6] - B[0] * B[7];
+  det = B[0] * (B[4] * B[8] - B[5] * B[7]) -
+        B[1] * (B[3] * B[8] - B[5] * B[6]) +
+        B[2] * (B[3] * B[7] - B[4] * B[6]);
+  idet = 1.0 / det;
 
-  Binv[2] = B[1] * B[5] - B[2] * B[4];
+#ifdef DEBUG 
-  Binv[5] = B[2] * B[3] - B[0] * B[5];
+  std::cerr << "Determinant of B = " << det << std::endl;
-  Binv[8] = B[0] * B[4] - B[1] * B[3];
+#endif
+
+  Binv[0] =   ( B[4] * B[8] - B[7] * B[5] ) * idet;
+  Binv[1] = - ( B[1] * B[8] - B[7] * B[2] ) * idet;
+  Binv[2] =   ( B[1] * B[5] - B[4] * B[2] ) * idet;
+  Binv[3] = - ( B[3] * B[8] - B[6] * B[5] ) * idet;
+  Binv[4] =   ( B[0] * B[8] - B[6] * B[2] ) * idet;
+  Binv[5] = - ( B[0] * B[5] - B[3] * B[2] ) * idet;
+  Binv[6] =   ( B[3] * B[7] - B[6] * B[4] ) * idet;
+  Binv[7] = - ( B[0] * B[7] - B[6] * B[1] ) * idet;
+  Binv[8] =   ( B[0] * B[4] - B[3] * B[1] ) * idet;
+
+#ifdef DEBUG
+  showMatrix2(Binv, 3, 3, "Binv");
+#endif
 
   // Check if determinant of inverted matrix is not zero
-  // If so, exigt and return false.
+  // double det;
-  double det;
+  det = Binv[0] * (Binv[4] * Binv[8] - Binv[5] * Binv[7]) -
-  det = B[0] * (B[4] * B[8] - B[5] * B[7]) -
+        Binv[1] * (Binv[3] * Binv[8] - Binv[5] * Binv[6]) +
-        B[1] * (B[3] * B[8] - B[5] * B[6]) + B[2] * (B[3] * B[7] - B[4] * B[6]);
+        Binv[2] * (Binv[3] * Binv[7] - Binv[4] * Binv[6]);
+
+#ifdef DEBUG
+  std::cerr << "Determinant of Binv = " << det << std::endl;
+#endif
+
   if (std::fabs(det) < threshold()) {
     std::cerr << "Determinant approached 0!" << std::endl;
     return false;
   }
 
-  // Compute (S + U * V)^{-1} with Woobury identity
+  // Compute B^{-1} x D
-  double D[3 * Dim];
-  matMul2(V, Slater_inv, D, 3, Dim, Dim);
   double tmp[3 * Dim];
   matMul2(Binv, D, tmp, 3, 3, Dim);
+
+#ifdef DEBUG
+  showMatrix2(tmp, 3, Dim, "tmp = Binv * D");
+#endif
+
+  // Compute C x B^{-1} x D
   double tmp2[Dim * Dim];
   matMul2(C, tmp, tmp2, Dim, 3, Dim);
+
+#ifdef DEBUG
+  showMatrix2(tmp2, Dim, Dim, "tmp2 = C * tmp");
+#endif
+
+  // Compute (S + U V)^{-1} = S^{-1} - C B^{-1} D
   for (unsigned int i = 0; i < Dim * Dim; i++) {
     Slater_inv[i] -= tmp2[i];
   }
+
+#ifdef DEBUG
+  showMatrix2(Slater_inv, Dim, Dim, "Slater_inv AFTER update");
+#endif
   return true;
 }
 

tests/QMCChem_dataset_test.f90

@@ -33,15 +33,15 @@ program QMCChem_dataset_test
     close(2000)
     close(3000)
 
-    !! Write Updates to file to check
+    ! !! Write Updates to file to check
-    open(unit = 2000, file = "Updates.dat")
+    ! open(unit = 2000, file = "Updates.dat")
-    do i=1,dim
+    ! do i=1,dim
-        do j=1,n_updates
+    !     do j=1,n_updates
-            write(2000,"(E23.15, 1X)", advance="no") Updates(i,j)
+    !         write(2000,"(E23.15, 1X)", advance="no") Updates(i,j)
-        end do
+    !     end do
-        write(2000,*)
+    !     write(2000,*)
-    end do
+    ! end do
-    close(2000)
+    ! close(2000)
 
     !! Update S & transform replacement updates 'Updates'
     !! into additive updates 'U' to compute the inverse
@@ -53,6 +53,16 @@ program QMCChem_dataset_test
         end do
     end do
 
+    !! Write Updates to file to check
+    open(unit = 2000, file = "Updates.dat")
+    do i=1,dim
+        do j=1,n_updates
+            write(2000,"(E23.15, 1X)", advance="no") U(i,j)
+        end do
+        write(2000,*)
+    end do
+    close(2000)
+
     !! Update S_inv
     !! S_inv needs to be transposed first before it
     !! goes to MaponiA3

tests/test_h5.cpp

@@ -52,8 +52,6 @@ int test_cycle(H5File file, int cycle, std::string version, double tolerance) {
   showMatrix(slater_inverse, dim, "OLD Inverse");
 #endif
 
-  showMatrix2(slater_matrix, dim, dim, "Slater");
-  
   // Transform replacement updates in 'updates[]' into additive updates in 'u[]'
   for (j = 0; j < nupdates; j++) {
     for (i = 0; i < dim; i++) {