shells/fem/smath.h

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/* -*- C -*- */
/*
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *                                   Fehmi Cirak
 *                        California Institute of Technology
 *                           (C) 2001 All Rights Reserved
 *
 * <LicenseText>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#ifndef SMATH_H
#define SMATH_H

#if defined(HAVE_CONFIG_H)
/* autoconf */
#include <config.h>
#elif defined(BLD_PROCEDURE)
/* build procedure */
#include <portinfo.h>
#endif


#ifdef __cplusplus
namespace shells {
#define DECLARE_EXTERN extern "C"
#else
#define DECLARE_EXTERN extern
#endif

    DECLARE_EXTERN double sinv3 (double [3][3]); 
    DECLARE_EXTERN void smulvec3 (double [3], double [3][3], double [3]); 
    DECLARE_EXTERN double ssppr3 (double [3], double [3], double [3]);      
    DECLARE_EXTERN void smult3 (double [3][3], double [3][3], double [3][3]); 
    DECLARE_EXTERN void smulvecTr3 (double a[3], double c[3][3], double b[3]); 
    DECLARE_EXTERN void stran3 (double a[3][3]); 
    DECLARE_EXTERN double snormalize3 (double a[3]); 

    static void szero3 (double a[3][3])    
        /* initialize a */
    {
        a[0][0] = 0.0;  a[0][1] = 0.0;  a[0][2] = 0.0;
        a[1][0] = 0.0;  a[1][1] = 0.0;  a[1][2] = 0.0;
        a[2][0] = 0.0;  a[2][1] = 0.0;  a[2][2] = 0.0;
    }

    

    static double sskpr3 (double a[3], double b[3]) 
    /* compute the scalarproduct scalar = a*b */       
    {              
        return a[0]*b[0]+a[1]*b[1]+a[2]*b[2];
    }
    


    static void skrpr3 (double c[3], double a[3], double b[3]) 
    /* compute the vectorproduct c=a x b */
    {
        c[0] = a[1]*b[2] - a[2]*b[1];
        c[1] = a[2]*b[0] - a[0]*b[2];
        c[2] = a[0]*b[1] - a[1]*b[0];
    }
    


    static void scopy3 (double a[3][3], double b[3][3]) 
    /* copy 3x3 matrix */       
    {
        a[0][0]=b[0][0]; a[0][1]=b[0][1]; a[0][2]=b[0][2];
        a[1][0]=b[1][0]; a[1][1]=b[1][1]; a[1][2]=b[1][2];
        a[2][0]=b[2][0]; a[2][1]=b[2][1]; a[2][2]=b[2][2];
    }
    
    
    
    static void smulscl3 (double scalar, double a[3][3]) 
    /* multipy a with a scalar */
    {
        a[0][0]*=scalar; a[0][1]*=scalar; a[0][2]*=scalar;
        a[1][0]*=scalar; a[1][1]*=scalar; a[1][2]*=scalar;
        a[2][0]*=scalar; a[2][1]*=scalar; a[2][2]*=scalar;
    }



    static void smulsclvec3 (double scalar, double a[3]) 
    /* multipy a with a scalar */
    {
        a[0]*=scalar;
        a[1]*=scalar;
        a[2]*=scalar; 
    }
    
    static void saverage3(double a[3], double b[3], double c[3]) 
    /* average vector */
    {
        a[0] = b[0];
        a[1] = b[1];
        a[2] = b[2];

        a[0] += c[0];
        a[1] += c[1];
        a[2] += c[2];
            
        a[0] *= 0.5;
        a[1] *= 0.5;
        a[2] *= 0.5;
    }
    
    static void sdifference3(double a[3], double b[3], double c[3]) 
    /* difference of two vectors */
    {
        a[0] = b[0];
        a[1] = b[1];
        a[2] = b[2];

        a[0] -= c[0];
        a[1] -= c[1];
        a[2] -= c[2];
    }

#ifdef __cplusplus
}
#endif

#undef DECLARE_EXTERN

#endif


/* End of file */

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