qmckl/org/qmckl_determinant.org

#+TITLE: Slater Determinant
#+SETUPFILE: ../tools/theme.setup
#+INCLUDE: ../tools/lib.org

The slater deteminant is required for the calculation of the
wavefunction, gradient, and derivatives. These quantities will be used
to calculate the local Energy (\[E_L\]).

ψ(x) = det|ϕ₁(x₁)...ϕᵢ(yᵢ)...ϕₙ(xₙ)|

Concerning the gradient and laplacian, in fact what is actually
calculated is the ratio of the gradient/laplacian and the determinant
of the slater matrix:

∇ψ(x)/ψ(x)

and

∇²ψ(x)/ψ(x)

This avoids the unnecessary multiplication and division of by the
determinant ψ(x).


* Headers                                                          :noexport:
  #+begin_src elisp :noexport :results none
(org-babel-lob-ingest "../tools/lib.org")
  #+end_src


  #+begin_src c :tangle (eval h_private_type)
#ifndef QMCKL_MO_HPT
#define QMCKL_MO_HPT

#include <stdbool.h>
  #+end_src

  #+begin_src c :tangle (eval c_test) :noweb yes
#include "qmckl.h"
#include "assert.h"
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <math.h>
#include "chbrclf.h"
#include "qmckl_ao_private_func.h"
#include "qmckl_mo_private_func.h"
#include "qmckl_determinant_private_func.h"

int main() {
    qmckl_context context;
    context = qmckl_context_create();

    qmckl_exit_code rc;
  #+end_src

  #+begin_src c :tangle (eval c)
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDINT_H
#include <stdint.h>
#elif HAVE_INTTYPES_H
#include <inttypes.h>
#endif

#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>

#include "qmckl.h"
#include "qmckl_context_private_type.h"
#include "qmckl_memory_private_type.h"
#include "qmckl_memory_private_func.h"
#include "qmckl_ao_private_type.h"
#include "qmckl_ao_private_func.h"
#include "qmckl_mo_private_type.h"
#include "qmckl_mo_private_func.h"
#include "qmckl_determinant_private_type.h"
#include "qmckl_determinant_private_func.h"
  #+end_src

* Context

  The following arrays are stored in the context:

  |-----------------+-------------------------------+------------------------------------|
  | ~type~          | ~char~                        | α (~'A'~) or β (~'B'~) determinant |
  | ~walk_num~      | ~int64_t~                    | Number of walkers                  |
  | ~det_num~       | ~int64_t~                    | Number of determinants per walker  |
  | ~fermi_num~     | ~int64_t~                    | Number of number of fermions       |
  | ~mo_index_list~ | ~mo_index[walk_num][det_num]~ | Index of MOs for each walker       |

  Computed data:
  
  |-------------------+------------------------------------------+----------------------------------------------------------------------------------------|
  | ~det_matrix_list~ | ~[walk_num][det_num][mo_num][fermi_num]~ | The slater matrix for each determinant of each walker.                                 |
  |-------------------+------------------------------------------+----------------------------------------------------------------------------------------|
  | ~det_vgl~         | ~[5][walk_num][det_num]~                 | Value, gradients, Laplacian of the MOs at electron positions                           |
  | ~det_vgl_date~    | ~int64_t~                               | Late modification date of Value, gradients, Laplacian of the MOs at electron positions |
  |-------------------+------------------------------------------+----------------------------------------------------------------------------------------|
  
** Data structure

   #+begin_src c :comments org :tangle (eval h_private_type)
typedef struct qmckl_determinant_struct {
  char      type;
  int64_t  walk_num;  
  int64_t  det_num;  
  int64_t  fermi_num;  
  int64_t* mo_index_list;

  double  * det_matrix_list;
  double  * det_vgl;
  int64_t   det_vgl_date;

  int32_t   uninitialized;
  bool      provided;
} qmckl_determinant_struct;
   #+end_src

   The ~uninitialized~ integer contains one bit set to one for each
   initialization function which has not been called. It becomes equal
   to zero after all initialization functions have been called. The
   struct is then initialized and ~provided == true~.
   Some values are initialized by default, and are not concerned by
   this mechanism.

** Access functions
   
   #+begin_src c :comments org :tangle (eval h_private_func) :exports none
char      qmckl_get_determinant_type             (const qmckl_context context);
int64_t   qmckl_get_determinant_walk_num           (const qmckl_context context);
int64_t   qmckl_get_determinant_det_num           (const qmckl_context context);
int64_t   qmckl_get_determinant_fermi_num           (const qmckl_context context);
int64_t*   qmckl_get_determinant_mo_index_list      (const qmckl_context context);
   #+end_src

   When all the data for the slater determinants have been provided, the following
   function returns ~true~.

   #+begin_src c :comments org :tangle (eval h_func)
bool      qmckl_mo_basis_provided           (const qmckl_context context);
   #+end_src

   #+NAME:post
   #+begin_src c :exports none
if ( (ctx->mo_basis.uninitialized & mask) != 0) {
  return NULL;
}
   #+end_src


   #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
char qmckl_get_determinant_type (const qmckl_context context) {

  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return (char) 0;
  }

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  int32_t mask = 1;

  if ( (ctx->determinant.uninitialized & mask) != 0) {
    return (char) 0;
  }

  assert (ctx->determinant.type != (char) 0);
  return ctx->determinant.type;
}

int64_t qmckl_get_determinant_walk_num (const qmckl_context context) {
  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return (int64_t) 0;
  }

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  int32_t mask = 1 << 1;

  if ( (ctx->determinant.uninitialized & mask) != 0) {
    return (int64_t) 0;
  }

  assert (ctx->determinant.walk_num > (int64_t) 0);
  return ctx->determinant.walk_num;
}

int64_t qmckl_get_determinant_det_num (const qmckl_context context) {
  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return (int64_t) 0;
  }

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  int32_t mask = 1 << 2;

  if ( (ctx->determinant.uninitialized & mask) != 0) {
    return (int64_t) 0;
  }

  assert (ctx->determinant.det_num > (int64_t) 0);
  return ctx->determinant.det_num;
}

int64_t qmckl_get_determinant_fermi_num (const qmckl_context context) {
  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return (int64_t) 0;
  }

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  int32_t mask = 1 << 3;

  if ( (ctx->determinant.uninitialized & mask) != 0) {
    return (int64_t) 0;
  }

  assert (ctx->determinant.fermi_num > (int64_t) 0);
  return ctx->determinant.fermi_num;
}

int64_t* qmckl_get_determinant_mo_index_list (const qmckl_context context) {
  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return (int64_t) 0;
  }

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  int32_t mask = 1 << 4;

  if ( (ctx->determinant.uninitialized & mask) != 0) {
    return (int64_t) 0;
  }

  assert (ctx->determinant.mo_index_list != NULL);
  return ctx->determinant.mo_index_list;
}

   #+end_src
  
** Initialization functions

   To set the basis set, all the following functions need to be
   called.

   #+begin_src c :comments org :tangle (eval h_func)
qmckl_exit_code  qmckl_set_determinant_type             (const qmckl_context context, const char *t);
qmckl_exit_code  qmckl_set_determinant_walk_num         (const qmckl_context context, const int64_t walk_num);
qmckl_exit_code  qmckl_set_determinant_det_num          (const qmckl_context context, const int64_t det_num);
qmckl_exit_code  qmckl_set_determinant_fermi_num        (const qmckl_context context, const int64_t fermi_num);
qmckl_exit_code  qmckl_set_determinant_mo_index_list    (const qmckl_context context, const int64_t* mo_index_list);
   #+end_src

   #+NAME:pre2
   #+begin_src c  :exports none
if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
  return QMCKL_NULL_CONTEXT;
 }

qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
   #+end_src

   #+NAME:post2
   #+begin_src c  :exports none
ctx->det.uninitialized &= ~mask;
ctx->det.provided = (ctx->det.uninitialized == 0);
if (ctx->det.provided) {
  qmckl_exit_code rc_ = qmckl_finalize_determinant(context);
  if (rc_ != QMCKL_SUCCESS) return rc_;
 }

return QMCKL_SUCCESS;
   #+end_src

   #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
qmckl_exit_code qmckl_set_determinant_type(qmckl_context context, const char t) {
  <<pre2>>

  if (t != 'G' && t != 'S') {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_set_determinant_type",
                           NULL);
  }

  int32_t mask = 1;
  ctx->determinant.type = t;

  <<post2>>
}

qmckl_exit_code qmckl_set_determinant_walk_num(qmckl_context context, const int64_t walk_num) {
  <<pre2>>

  if (walk_num <= 0) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_set_determinant_walk_num",
                           "walk_num <= 0");
  }

  int32_t mask = 1 << 1;
  ctx->determinant.walk_num = walk_num;

  <<post2>>
}

qmckl_exit_code qmckl_set_determinant_det_num(qmckl_context context, const int64_t det_num) {
  <<pre2>>

  if (det_num <= 0) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_set_determinant_det_num",
                           "det_num <= 0");
  }

  int32_t mask = 1 << 2;
  ctx->determinant.det_num = det_num;

  <<post2>>
}

qmckl_exit_code qmckl_set_determinant_fermi_num(qmckl_context context, const int64_t fermi_num) {
  <<pre2>>

  if (fermi_num <= 0) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_set_slater_fermierminant_det_num",
                           "fermi_num <= 0");
  }

  int32_t mask = 1 << 3;
  ctx->determinant.fermi_num = fermi_num;

  <<post2>>
}

qmckl_exit_code  qmckl_set_determinant_mo_index_list(qmckl_context context, const int64_t* mo_index_list) {
  <<pre2>>

  int32_t mask = 1 << 4;

  if (ctx->determinant.mo_index_list != NULL) {
    qmckl_exit_code rc = qmckl_free(context, ctx->determinant.mo_index_list);
    if (rc != QMCKL_SUCCESS) {
      return qmckl_failwith( context, rc,
                             "qmckl_set_determinant_mo_index_list",
                             NULL);
    }
  }

  qmckl_memory_info_struct mem_info = qmckl_memory_info_struct_zero;
  mem_info.size = ctx->determinant.walk_num * ctx->determinant.det_num * sizeof(int64_t);
  int64_t* new_array = (int64_t*) qmckl_malloc(context, mem_info);
  if (new_array == NULL) {
    return qmckl_failwith( context,
                           QMCKL_ALLOCATION_FAILED,
                           "qmckl_set_determinant_mo_index_list",
                           NULL);
  }

  memcpy(new_array, mo_index_list, mem_info.size);

  ctx->determinant.mo_index_list = new_array;

  <<post2>>
}

   #+end_src

 When the basis set is completely entered, other data structures are
 computed to accelerate the calculations.

   #+begin_src c :comments org :tangle (eval h_private_func) :noweb yes :exports none
qmckl_exit_code qmckl_finalize_basis(qmckl_context context);
   #+end_src

   #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
qmckl_exit_code qmckl_finalize_determinant(qmckl_context context) {
}
   #+end_src

** Fortran Interfaces

** Test
* Computation
   :PROPERTIES:
   :Name:     qmckl_compute_determinant_det_vgl
   :CRetType: qmckl_exit_code
   :FRetType: qmckl_exit_code
   :END:

*** Get
    #+NAME: qmckl_get_determinant_det_vgl_args
   | ~qmckl_context~ | ~context~                               | in  | Global state                              |
   | ~double~        | ~det_vgl[5][walk_num][det_num]~ | out | Value, gradients and Laplacian of the MOs |
    
    #+begin_src c :comments org :tangle (eval h_func) :noweb yes
qmckl_exit_code qmckl_get_determinant_det_vgl(qmckl_context context, double* const det_vgl);
    #+end_src

    #+begin_src c :comments org :tangle (eval c) :noweb yes  :exports none
qmckl_exit_code qmckl_get_determinant_det_vgl(qmckl_context context, double * const det_vgl)
  
  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return QMCKL_NULL_CONTEXT;
  }

  qmckl_exit_code rc;

  rc = qmckl_provide_ao_vgl(context);
  if (rc != QMCKL_SUCCESS) return rc;

  rc = qmckl_provide_mo_vgl(context);
  if (rc != QMCKL_SUCCESS) return rc;

  rc = qmckl_provide_det_vgl(context);
  if (rc != QMCKL_SUCCESS) return rc;

  qmckl_context_struct* const ctx = (qmckl_context_struct* const) context;
  assert (ctx != NULL);

  size_t sze = 5 * ctx->det.det_num * ctx->det.walk_num;
  memcpy(det_vgl, ctx->det.det_vgl, sze * sizeof(double));

  return QMCKL_SUCCESS;
}
    #+end_src

   #+CALL: generate_c_header(table=qmckl_get_determinant_det_vgl_args,rettyp=get_value("CRetType"),fname="qmckl_compute_get_determinant_det_vgl"))

   #+RESULTS:
   #+begin_src c :tangle (eval h_func) :comments org
   qmckl_exit_code qmckl_compute_get_determinant_det_vgl (
	 const qmckl_context context,
	 double* const det_vgl ); 
   #+end_src
     
    #+CALL: generate_c_interface(table=qmckl_get_determinant_det_vgl_args,rettyp=get_value("CRetType"),fname="qmckl_compute_get_determinant_det_vgl"))

    #+RESULTS:
    #+begin_src f90 :tangle (eval f) :comments org :exports none
    integer(c_int32_t) function qmckl_compute_get_determinant_det_vgl &
	(context, det_vgl) &
	bind(C) result(info)

      use, intrinsic :: iso_c_binding
      implicit none

      integer (c_int64_t) , intent(in)  , value :: context
      real    (c_double ) , intent(out)         :: det_vgl(det_num,walk_num,5)

      integer(c_int32_t), external :: qmckl_compute_get_determinant_det_vgl_f
      info = qmckl_compute_get_determinant_det_vgl_f &
	     (context, det_vgl)

    end function qmckl_compute_get_determinant_det_vgl
    #+end_src
*** Provide
*** Compute
*** Test

* End of files                                                     :noexport:

  #+begin_src c :tangle (eval h_private_type)
#endif
  #+end_src

*** Test
  #+begin_src c :tangle (eval c_test)
    rc = qmckl_context_destroy(context);
    assert (rc == QMCKL_SUCCESS);

    return 0;
}
  #+end_src

*** Compute file names
    #+begin_src emacs-lisp
; The following is required to compute the file names

(setq pwd (file-name-directory buffer-file-name))
(setq name (file-name-nondirectory (substring buffer-file-name 0 -4)))
(setq f  (concat pwd name "_f.f90"))
(setq fh (concat pwd name "_fh.f90"))
(setq c  (concat pwd name ".c"))
(setq h  (concat name ".h"))
(setq h_private  (concat name "_private.h"))
(setq c_test  (concat pwd "test_" name ".c"))
(setq f_test  (concat pwd "test_" name "_f.f90"))

; Minted
(require 'ox-latex)
(setq org-latex-listings 'minted)
(add-to-list 'org-latex-packages-alist '("" "listings"))
(add-to-list 'org-latex-packages-alist '("" "color"))

    #+end_src


# -*- mode: org -*-
# vim: syntax=c