Return to hexa.fnc CVS log

Up to [local] / OpenXM_contrib / gnuplot / demo

Annotation of OpenXM_contrib/gnuplot/demo/hexa.fnc, Revision 1.1.1.1

1.1       maekawa     1: #
                      2: #   Use this function to fit sound velocity data as function of
                      3: #   sound propagation direction, indicated by its angle against the
                      4: #   z-axis of an hexagonal symmetry coordinate system
                      5: #
                      6: #   Adjustable parameters:
                      7: #
                      8: #   c33, c11, c13, c44         elastic moduli - materials constants
                      9: #   phi0                       angle offset
                     10: #
                     11: # HBB 970522: factored out common factor 1e9 from c?? into the
                     12: #  function, to improve the fit convergence. Fit parameters were
                     13: #  just too grossly different before.
                     14:
                     15: rho         = 1000.0         # density in kg/m3
                     16:
                     17: phi(x)     = (x - phi0)/360.0*2.0*pi
                     18:
                     19: main(x)     = c11*sin(phi(x))**2 + c33*cos(phi(x))**2 + c44
                     20: mixed(x)    = sqrt( ((c11-c44)*sin(phi(x))**2                          \
                     21:                     +(c44-c33)*cos(phi(x))**2)**2  \
                     22:                    +(2.0*(c13+c44)*sin(phi(x))*cos(phi(x)))**2 )
                     23:
                     24: vlong(x)    = sqrt(1.0/2.0/rho*1e9*(main(x) + mixed(x)))
                     25: vtrans(x)   = sqrt(1.0/2.0/rho*1e9*(main(x) - mixed(x)))
                     26:
                     27: # When we read the file in, we set y=index, and we use
                     28: # y in this (pseudo) 3d fit to choose an x function
                     29:
                     30: f(x,y) =  y==1  ?  vlong(x)  :  vtrans(x)