NAMD: Settle.h Source File

00001 
00007 #ifndef SETTLE_H__
00008 #define SETTLE_H__
00009 
00010 #include "Vector.h"
00011 #include "Tensor.h"
00012 
00013 /*
00014 
00015 Oxygen at a0, hydrogens at b0, c0, center of mass at the origin.
00016 
00017                    |
00018                    |
00019                    |
00020                 a0 .-------
00021                    |   |
00022                    |   ra
00023                    |   | 
00024 ---------------------------------------
00025            |       |        |
00026            rb      |---rc---|
00027            |       |        |
00028     b0 .-----------|        c0 .
00029   
00030 SETTLE for step one of velocity verlet.
00031 ref: positions before unconstrained step
00032 mass: masses
00033 pos: on input: positions after unconstrained step; on output: the new 
00034                positions.
00035 vel: on input: velocities after unconstrained step; on output: the new
00036                velocities.
00037 ra, rb, rc: canonical positions of water atoms; see above diagram
00038 */
00039 
00041 extern int settle1isinitted(void);
00042 
00044 extern int settle1init(BigReal mO, BigReal mH, BigReal hhdist, BigReal ohdist);
00045 
00047 extern int settle1(const Vector *ref, Vector *pos, Vector *vel, BigReal invdt);
00048 
00049 extern int settle2(BigReal mO, BigReal mH, const Vector *pos,
00050                    Vector *vel, BigReal dt, Tensor *virial); 
00051 #endif