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Update determinant in qmckl_sherman_morrison

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This commit is contained in:
Pablo Oliveira 2021-10-13 10:31:24 +02:00
parent b0fa668c77
commit b05390a273
1 changed files with 23 additions and 4 deletions
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27
org/qmckl_sherman_morrison_woodbury.org
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@ -60,6 +60,9 @@ int main() {
the update is applied as usual and the kernel exits with return code \texttt{QMCKL_SUCCESS}.
If $1+v_j^TS^{-1}u_j \leq \epsilon$ the update is rejected and the kernel exits with return code \texttt{QMCKL_FAILURE}.
If the determinant of the Slater-matrix is passed, it will be updated to the determinant resulting
from applying the updates to the original matrix.
#+NAME: qmckl_sherman_morrison_args
| qmckl_context | context | in | Global state |
| uint64_t | Dim | in | Leading dimension of Slater_inv |
@ -68,6 +71,7 @@ int main() {
| uint64_t | Updates_index[N_updates] | in | Array containing the rank-1 updates |
| double | breakdown | in | Break-down parameter on which to fail or not |
| double | Slater_inv[Dim*Dim] | inout | Array containing the inverse of a Slater-matrix |
| double* | determinant | inout | det(Slater) the determinant of the Slater-matrix |
*** Requirements
@ -92,7 +96,8 @@ int main() {
const double* Updates,
const uint64_t* Updates_index,
const double breakdown,
double* Slater_inv);
double* Slater_inv,
double* determinant);
#+end_src
*** C source
@ -108,7 +113,8 @@ qmckl_exit_code qmckl_sherman_morrison(const qmckl_context context,
const double* Updates,
const uint64_t* Updates_index,
const double breakdown,
double* Slater_inv) {
double* Slater_inv,
double* determinant) {
if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
return QMCKL_NULL_CONTEXT;
@ -130,11 +136,16 @@ qmckl_exit_code qmckl_sherman_morrison(const qmckl_context context,
// Denominator
double den = 1 + C[Updates_index[l] - 1];
if (fabs(den) < breakdown) {
return QMCKL_FAILURE;
}
double iden = 1 / den;
// Update det(A)
if (determinant != NULL)
*determinant *= den;
// D = v^T x A^{-1}
for (uint64_t j = 0; j < Dim; j++) {
D[j] = Slater_inv[(Updates_index[l] - 1) * Dim + j];
@ -174,7 +185,7 @@ qmckl_exit_code qmckl_sherman_morrison(const qmckl_context context,
#+begin_src f90 :tangle (eval fh_func) :comments org :exports none
interface
integer(c_int32_t) function qmckl_sherman_morrison &
(context, Dim, N_updates, Updates, Updates_index, breakdown, Slater_inv) &
(context, Dim, N_updates, Updates, Updates_index, breakdown, Slater_inv, determinant) &
bind(C)
use, intrinsic :: iso_c_binding
@ -188,6 +199,7 @@ qmckl_exit_code qmckl_sherman_morrison(const qmckl_context context,
integer (c_int64_t) , intent(in) :: Updates_index(N_updates)
real (c_double ) , intent(in) , value :: breakdown
real (c_double ) , intent(inout) :: Slater_inv(Dim*Dim)
real (c_double ) , intent(inout) :: determinant
end function qmckl_sherman_morrison
end interface
@ -234,7 +246,14 @@ double Slater_inv5[441] = {-0.054189244668834902, -105.426713929607, -88.4584964
assert(Updates1 != NULL);
assert(Updates_index1 != NULL);
assert(Slater_inv1 != NULL);
rc = qmckl_sherman_morrison(context, Dim, N_updates1, Updates1, Updates_index1, breakdown, Slater_inv1);
// original determinant of Slater1 (before applying updates)
double det = 3.407025646103221e-10;
rc = qmckl_sherman_morrison(context, Dim, N_updates1, Updates1, Updates_index1, breakdown, Slater_inv1, &det);
// Check that the determinant is updated properly
assert(fabs(det - 4.120398385068217e-10) < 1e-8);
for (unsigned int i = 0; i < Dim; i++) {
for (unsigned int j = 0; j < Dim; j++) {
res[i * Dim + j] = 0;