Electrons

1. Context

1 Context

The following data stored in the context:

`date`	uint64_t	Last modification date of the coordinates
`uninitialized`	int32_t	Keeps bit set for uninitialized data
`num`	int64_t	Total number of electrons
`up_num`	int64_t	Number of up-spin electrons
`down_num`	int64_t	Number of down-spin electrons
`walk_num`	int64_t	Number of walkers
`provided`	bool	If true, `electron` is valid
`coord_new`	double[walk_num][3][num]	New set of electron coordinates
`coord_old`	double[walk_num][3][num]	Old set of electron coordinates

1.1 Data structure

typedef struct qmckl_electron_struct {
  int64_t   date;
  int64_t   num;
  int64_t   up_num;
  int64_t   down_num;
  int64_t   walk_num;
  double*   coord_new;
  double*   coord_old;
  int32_t   uninitialized;
  bool      provided;
} qmckl_electron_struct;

The uninitialized integer contains one bit set to one for each initialization function which has not bee called. It becomes equal to zero after all initialization functions have been called. The struct is then initialized and provided == true.

1.2 Access functions

When all the data relative to electrons have been set, the following function returns true.

bool      qmckl_electron_provided       (const qmckl_context context);

1.3 Initialization functions

To set the data relative to the electrons in the context, the following functions need to be called. When the data structure is initialized, the coord_new and coord_old arrays are both allocated.

qmckl_exit_code  qmckl_set_electron_num        (qmckl_context context, const int64_t up_num, const int64_t down_num);
qmckl_exit_code  qmckl_set_electron_walk_num   (qmckl_context context, const int64_t walk_num);
qmckl_exit_code  qmckl_set_electron_coord      (qmckl_context context, const double* coord);

To set the number of electrons, we give the number of up-spin and down-spin electrons to the context and we set the number of walkers.

The following function sets the electron coordinates of all the walkers. When this is done, the pointers to the old and new sets of coordinates are swapped, and the new coordinates are overwritten. This can be done only when the data relative to electrons have been set.

1.4 Test

/* Reference input data */

#define up_num      ((int64_t) 3)
#define down_num    ((int64_t) 2)
#define walk_num    ((int64_t) 2)
#define num         (up_num+down_num)

double coord[walk_num*3*num] =
  { 7.303633091022677881e+00, 1.375868694453235719e+01, 1.167371490471771217e-01,                   
    4.547755371567960836e+00, 3.245907105524011182e+00, 2.410764357550297110e-01,
    5.932816068137344523e+00, 1.491671465549257469e+01, 3.825374039119375236e-01,
    7.347336142660052083e+00, 1.341946976062362129e+00, 1.648917914228352322e+00,
    5.735221530102248444e+00, 1.064667491680036271e+01, 4.227201772236627297e-01,
    8.099550978782254163e+00, 6.861498941099086757e+00, 4.015884841159429036e-02,
    1.014757367558326173e+01, 5.219335322173662917e+00, 5.037004126899931322e-02,
    1.484094322159507051e+01, 9.777903829455864226e+00, 5.243007994024882767e-02,
    9.081723054990456845e+00, 5.499568496038920173e+00, 2.910446438899221347e-02,
    2.583154239492383653e+00, 1.442282811294904432e+00, 6.387191629878670451e-02 };

/* --- */

qmckl_exit_code rc;

munit_assert(!qmckl_electron_provided(context));

rc = qmckl_set_electron_num (context, up_num, down_num);
munit_assert_int64(rc, ==, QMCKL_SUCCESS);
munit_assert(!qmckl_electron_provided(context));

rc = qmckl_set_electron_walk_num (context, walk_num);
munit_assert_int64(rc, ==, QMCKL_SUCCESS);
munit_assert(qmckl_electron_provided(context));

rc = qmckl_set_electron_coord (context, coord);
munit_assert_int64(rc, ==, QMCKL_SUCCESS);