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41 #define FLAG_VOLUME 02
42 #define FLAG_ATOM_AREA 04
46 extern int nsc_dclm_pbc(rvec *coords, real *radius, int nat,
48 real *value_of_area, real **at_area,
50 real **lidots, int *nu_dots,
51 atom_id index[],int ePBC,matrix box);
55 The input requirements :
56 The arrays with atom coordinates and radii are thought to start
57 with index 0, i.e., places 0, 1, and 2 are the x-, y-, and z-
58 coordinates of the zero-th atom and place 0 in the other array
61 PLEASE TAKE INTO ACCOUNT THAT THE RADII GIVEN HERE ARE DIRECTLY
62 USED FOR SURFACE CALCULATION. NSC does not increment with a probe
65 The user can define any number of dots. The program selects a
66 dot density that is the lowest possible with at least the required
67 number of dots. The points are distributed in accordance with the
68 icosahedron-based or the dodecahedron-based method as described in
71 The output requirements are :
72 1 and 3 : pointer to an existing real
73 2 and 4 : pointer to an existing pointer to real
74 NSC allocates memory for an array
75 5 : pointer to an existing integer
77 The subroutine NSC makes use of variant 2 described in reference 1.
78 By selecting the necessary output via flags, the requirements for
79 cpu-time and computer memory can be adapted to the actual needs.
81 Example : flag = FLAG_VOLUME | FLAG_ATOM_AREA | FLAG_DOTS
82 The routine calculates the area, volume and the dot surface. The
83 program allocates arrays for the atomwise areas and for the surface
84 dots. The addresses are returned in the pointers to pointers to
86 This variant is not recommended because normally the dot surface
87 is needed for low point density (e.g.42) at which area and volume
88 are inaccurate. The sign "|" is used as binary AND !
90 flag = FLAG_VOLUME | FLAG_ATOM_AREA
91 In this case the large arrays for storing the surface dots
92 are not allocated. A large point number of the fully accessible
93 sphere can be selected. Good accuracy is already achieved with
94 600-700 points per sphere (accuracy of about 1.5 square Angstrem
96 Output pointers 4 and 5 may be NULL.
99 Only the dot surface is produced.
100 Output pointers 2 and 3 may be NULL.
102 The output pointer 1 cannot be set to NULL in any circumstances. The
103 overall area value is returned in every mode.
105 All files calling NSC should include nsc.h !!
108 Example for calling NSC (contents of user file):
113 int routine_calling_NSC(int n_atom, real *coordinates, real *radii) {
114 real area, volume, *atomwise_area, *surface_dots;
115 int i, density = 300, n_dots;
119 for (i=0; i<n_atom; i++) {
120 radii[i] += 1.4 /# add the probe radius if necessary #/
122 if (NSC(coordinates, radii, n_atom, density,
123 FLAG_AREA | FLAG_VOLUME | FLAG_DOTS,
124 &area, &atomwise_area, &volume, &surface_dots, &n_dots))
125 printf("error occured\n");
131 /# do something with areas, volume and surface dots #/