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

This data structure contains cartesian coordinates where the functions
will be evaluated. For DFT codes these may be the integration grid
points. For QMC codes, these are the electron coordinates of all the
walkers.

* 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_POINT_HPT
#define QMCKL_POINT_HPT
#include <stdbool.h>
  #+end_src

  #+begin_src c :tangle (eval h_private_func)
#ifndef QMCKL_POINT_HPF
#define QMCKL_POINT_HPF
  #+end_src

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

#include "chbrclf.h"

int main() {
  qmckl_context context;
  context = qmckl_context_create();
  #+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 <math.h>

#include <stdio.h>

#include "qmckl.h"
#include "qmckl_context_private_type.h"
#include "qmckl_memory_private_type.h"
#include "qmckl_memory_private_func.h"
#include "qmckl_point_private_func.h"
  #+end_src

* Context

  The following data stored in the context:

  | Variable  | Type          | Description            |
  |-----------+---------------+------------------------|
  | ~num~     | ~int64_t~     | Total number of points |
  | ~coord_x~ | ~double[num]~ | X coordinates          |
  | ~coord_y~ | ~double[num]~ | Y coordinates          |
  | ~coord_z~ | ~double[num]~ | Z coordinates          |

  We consider that 'transposed' and 'normal' storage follows the convention:

  |         | Normal           | Transposed       |
  |---------+------------------+------------------|
  | C       | ~[point_num][3]~ | ~[3][point_num]~ |
  | Fortran | ~(3,point_num)~  | ~(point_num,3)~  |

** Data structure

   #+begin_src c :comments org :tangle (eval h_private_type)
typedef struct qmckl_point_struct {
  double*   coord_x;
  double*   coord_y;
  double*   coord_z;
  int64_t   num;
} qmckl_point_struct;

   #+end_src

   #+begin_src c :comments org :tangle (eval h_private_func) 
qmckl_exit_code qmckl_init_point(qmckl_context context);
   #+end_src
   
   #+begin_src c :comments org :tangle (eval c)
qmckl_exit_code qmckl_init_point(qmckl_context context) {

  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return false;
  }

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

  qmckl_memory_info_struct mem_info = qmckl_memory_info_struct_zero;
  mem_info.size = sizeof(qmckl_point_struct);
  ctx->point = (qmckl_point_struct*) qmckl_malloc(context, mem_info);
  if (ctx->point == NULL) {
    return qmckl_failwith( context,
                           QMCKL_ALLOCATION_FAILED,
                           "qmckl_init_point",
                           NULL);
  }
  memset(ctx->point, 0, sizeof(qmckl_point_struct)); 

  return QMCKL_SUCCESS;
}
   #+end_src

** Access functions

   Access functions return ~QMCKL_SUCCESS~ when the data has been
   successfully retrieved. They return ~QMCKL_INVALID_CONTEXT~ when
   the context is not a valid context. If the function returns
   successfully, the variable pointed by the pointer given in argument
   contains the requested data. Otherwise, this variable is untouched.

*** Number of points

   #+begin_src c :comments org :tangle (eval h_func) :exports none
qmckl_exit_code qmckl_get_point_num (const qmckl_context context, int64_t* const num);
      #+end_src

       Returns the number of points stored in the context.
       
   #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
qmckl_exit_code
qmckl_get_point_num (const qmckl_context context, int64_t* const num) {

  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return QMCKL_INVALID_CONTEXT;
  }

  if (num == NULL) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_get_point_num",
                           "num is a null pointer");
  }

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

  assert (ctx->point->num > (int64_t) 0);
  ,*num = ctx->point->num;
  return QMCKL_SUCCESS;
}
      #+end_src

   #+begin_src f90 :comments org :tangle (eval fh_func) :noweb yes
interface
  integer(c_int32_t) function qmckl_get_point_num(context, num) bind(C)
    use, intrinsic :: iso_c_binding
    import
    implicit none

    integer (c_int64_t) , intent(in)  , value :: context                                  
    integer (c_int64_t) , intent(out)         :: num 
  end function
end interface
   #+end_src

*** Point coordinates
    
  #+begin_src c :comments org :tangle (eval h_func) :exports none
qmckl_exit_code qmckl_get_point(const qmckl_context context,
                                double* const coord,
                                const int64_t size_max);
  #+end_src

    Returns the point coordinates as sequences of (x,y,z).
    The pointer is assumed to point on a memory block of size
    ~size_max~ \ge ~3 * point_num~.

  #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
qmckl_exit_code
qmckl_get_point(const qmckl_context context,
                double* const coord,
                const int64_t size_max)
{

  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return QMCKL_INVALID_CONTEXT;
  }

  if (coord == NULL) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_get_point_coord",
                           "coord is a null pointer");
  }

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

  int64_t point_num = ctx->point->num;

  assert (ctx->point->coord_x != NULL);
  assert (ctx->point->coord_y != NULL);
  assert (ctx->point->coord_z != NULL);

  if (size_max < 3*point_num) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_3,
                           "qmckl_get_point_coord",
                           "size_max too small");
  }


  double * ptr = coord;
  for (int64_t i=0 ; i<point_num ; ++i) {
    ,*ptr = ctx->point->coord_x[i]; ++ptr;
    ,*ptr = ctx->point->coord_y[i]; ++ptr;
    ,*ptr = ctx->point->coord_z[i]; ++ptr;
  }
  
  return QMCKL_SUCCESS;
}

      #+end_src

  #+begin_src f90 :comments org :tangle (eval fh_func) :noweb yes
interface
  integer(c_int32_t) function qmckl_get_point(context, coord, size_max) bind(C)
    use, intrinsic :: iso_c_binding
    import
    implicit none

    integer (c_int64_t) , intent(in)  , value :: context
    real    (c_double ) , intent(out)         :: coord(*)
    integer (c_int64_t) , intent(in)          :: size_max
  end function
end interface
   #+end_src

      
  #+begin_src c :comments org :tangle (eval h_func) :exports none
qmckl_exit_code qmckl_get_point_xyz (const qmckl_context context,
                                     double* const coord_x,
                                     double* const coord_y,
                                     double* const coord_z,
                                     const int64_t size_max);
     #+end_src

    Returns the point coordinates in three different arrays, one for
    each component x,y,z.
    The pointers are assumed to point on a memory block of size
    ~size_max~ \ge ~point_num~.

  #+begin_src c :comments org :tangle (eval c) :noweb yes :exports none
qmckl_exit_code
qmckl_get_point_xyz (const qmckl_context context,
                     double* const coord_x,
                     double* const coord_y,
                     double* const coord_z,
                     const int64_t size_max)
{

  if (qmckl_context_check(context) == QMCKL_NULL_CONTEXT) {
    return QMCKL_INVALID_CONTEXT;
  }

  if (coord_x == NULL) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_2,
                           "qmckl_get_point_coord_xyz",
                           "coord_x is a null pointer");
  }

  if (coord_y == NULL) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_3,
                           "qmckl_get_point_coord_xyz",
                           "coord_y is a null pointer");
  }

  if (coord_z == NULL) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_4,
                           "qmckl_get_point_coord_xyz",
                           "coord_z is a null pointer");
  }

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

  int64_t point_num = ctx->point->num;

  assert (ctx->point->coord_x != NULL);
  assert (ctx->point->coord_y != NULL);
  assert (ctx->point->coord_z != NULL);

  if (size_max < point_num) {
    return qmckl_failwith( context,
                           QMCKL_INVALID_ARG_5,
                           "qmckl_get_point_coord_xyz",
                           "size_max too small");
  }

  memcpy(coord_x, ctx->point->coord_x, point_num*sizeof(double));
  memcpy(coord_y, ctx->point->coord_y, point_num*sizeof(double));
  memcpy(coord_z, ctx->point->coord_z, point_num*sizeof(double));
  
  return QMCKL_SUCCESS;
}
  #+end_src

  #+begin_src f90 :comments org :tangle (eval fh_func) :noweb yes
interface
  integer(c_int32_t) function qmckl_get_point_xyz(context, &
       coord_x, coord_y, coord_z, size_max) bind(C)
    use, intrinsic :: iso_c_binding
    import
    implicit none

    integer (c_int64_t) , intent(in)  , value :: context
    real    (c_double ) , intent(out)         :: coord_x(*)
    real    (c_double ) , intent(out)         :: coord_y(*)
    real    (c_double ) , intent(out)         :: coord_z(*)
    integer (c_int64_t) , intent(in)          :: size_max
  end function
end interface
   #+end_src

** Initialization functions

   When the data is set in the context, if the arrays are large
   enough, we overwrite the data contained in them.
   
   #+NAME: check_alloc
   #+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;
  assert (ctx != NULL);
  assert (ctx->point != NULL);

  if (ctx->point->num < num) {

    if (ctx->point->coord_x != NULL) {
      qmckl_free(context, ctx->point->coord_x);
      ctx->point->coord_x = NULL;
    }

    if (ctx->point->coord_y != NULL) {
      qmckl_free(context, ctx->point->coord_y);
      ctx->point->coord_y = NULL;
    }

    if (ctx->point->coord_z != NULL) {
      qmckl_free(context, ctx->point->coord_z);
      ctx->point->coord_z = NULL;
    }

    qmckl_memory_info_struct mem_info = qmckl_memory_info_struct_zero;
    mem_info.size = num*sizeof(double);

    ctx->point->coord_x = (double*) qmckl_malloc(context, mem_info);
    if (ctx->point->coord_x == NULL) {
      return qmckl_failwith( context,
                             QMCKL_ALLOCATION_FAILED,
                             "qmckl_set_point",
                             NULL);
    }

    ctx->point->coord_y = (double*) qmckl_malloc(context, mem_info);
    if (ctx->point->coord_y == NULL) {
      return qmckl_failwith( context,
                             QMCKL_ALLOCATION_FAILED,
                             "qmckl_set_point",
                             NULL);
    }

    ctx->point->coord_z = (double*) qmckl_malloc(context, mem_info);
    if (ctx->point->coord_z == NULL) {
      return qmckl_failwith( context,
                             QMCKL_ALLOCATION_FAILED,
                             "qmckl_set_point",
                             NULL);
    }
  };

  ctx->point->num = num;
   #+end_src

   To set the data relative to the points in the context, one of the
   following functions need to be called. 
   
   #+begin_src c :comments org :tangle (eval h_func)
qmckl_exit_code qmckl_set_point (qmckl_context context,
                                 const double* coord,
                                 const int64_t num);
   #+end_src

   Copy a sequence of (x,y,z) into the context.

   #+begin_src c :comments org :tangle (eval c) :noweb yes
qmckl_exit_code
qmckl_set_point (qmckl_context context,
                 const double* coord,
                 const int64_t num)
{
  
  <<check_alloc>>

  for (int64_t i=0 ; i<num ; ++i) {
    ctx->point->coord_x[i] = coord[3*i  ];
    ctx->point->coord_y[i] = coord[3*i+1];
    ctx->point->coord_z[i] = coord[3*i+2];
  }

  return QMCKL_SUCCESS;

}
   #+end_src

   #+begin_src f90 :comments org :tangle (eval fh_func) :noweb yes
interface
  integer(c_int32_t) function qmckl_set_point(context, &
       coord_x, coord_y, coord_z, size_max) bind(C)
    use, intrinsic :: iso_c_binding
    import
    implicit none

    integer (c_int64_t) , intent(in)  , value :: context
    real    (c_double ) , intent(in)          :: coord_x(*)
    real    (c_double ) , intent(in)          :: coord_y(*)
    real    (c_double ) , intent(in)          :: coord_z(*)
    integer (c_int64_t) , intent(in)  , value :: size_max
  end function
end interface
   #+end_src

   #+begin_src c :comments org :tangle (eval h_func)
qmckl_exit_code qmckl_set_point_xyz (qmckl_context context,
                                 const double* coord_x,
                                 const double* coord_y,
                                 const double* coord_z,
                                 const int64_t num);
   #+end_src

   #+begin_src c :comments org :tangle (eval c) :noweb yes
qmckl_exit_code
qmckl_set_point_xyz (qmckl_context context,
                     const double* coord_x,
                     const double* coord_y,
                     const double* coord_z,
                     const int64_t num)
{
  
  <<check_alloc>>

  memcpy(ctx->point->coord_x, coord_x, num*sizeof(double));
  memcpy(ctx->point->coord_y, coord_y, num*sizeof(double));
  memcpy(ctx->point->coord_z, coord_z, num*sizeof(double));

  return QMCKL_SUCCESS;
}
   #+end_src

   #+begin_src f90 :comments org :tangle (eval fh_func) :noweb yes
interface
  integer(c_int32_t) function qmckl_set_point_xyz(context, &
       coord_x, coord_y, coord_z, size_max) bind(C)
    use, intrinsic :: iso_c_binding
    import
    implicit none

    integer (c_int64_t) , intent(in)  , value :: context
    real    (c_double ) , intent(in)          :: coord_x(*)
    real    (c_double ) , intent(in)          :: coord_y(*)
    real    (c_double ) , intent(in)          :: coord_z(*)
    integer (c_int64_t) , intent(in)  , value :: size_max
  end function
end interface
   #+end_src

** Test

   #+begin_src c :tangle (eval c_test)
/* Reference input data */
int64_t point_num = chbrclf_elec_num;
double* coord     = &(chbrclf_elec_coord[0][0][0]);

/* --- */

qmckl_exit_code rc;

rc = qmckl_set_point (context, coord, point_num);
assert(rc == QMCKL_SUCCESS);

int64_t n;
rc = qmckl_get_point_num (context, &n);
assert(rc == QMCKL_SUCCESS);
assert(n == point_num);

double coord2[point_num*3];
double coord_x[point_num];
double coord_y[point_num];
double coord_z[point_num];

rc = qmckl_get_point_xyz (context, coord_x, coord_y, coord_z, point_num);
assert(rc == QMCKL_SUCCESS);

rc = qmckl_get_point (context, coord2, (point_num*3));
assert(rc == QMCKL_SUCCESS);

for (int64_t i=0 ; i<3*point_num ; ++i) {
  assert( coord[i] == coord2[i] );
}

for (int64_t i=0 ; i<point_num ; ++i) {
  assert( coord[3*i+0] == coord_x[i] );
  assert( coord[3*i+1] == coord_y[i] );
  assert( coord[3*i+2] == coord_z[i] );
}

    #+end_src

* End of files                                                     :noexport:

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

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

*** Test
  #+begin_src c :tangle (eval c_test)
  if (qmckl_context_destroy(context) != QMCKL_SUCCESS)
    return QMCKL_FAILURE;
  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

    #+RESULTS:
    |   | color    |
    |   | listings |


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