source: trunk/User form factors for Irena/TriaxialEllipsoid.ipf

#pragma TextEncoding = "UTF-8"
#pragma rtGlobals=3             // Use modern global access method and strict wave access.



//****************************************************************************************************
//this is Irena Modeling package User form factor.
//to use, open Modeling package, switch to Model controls and select "User" for Form Factor. 
Function TriaxSpheroid(Q,radius, par1,par2,par3,par4,par5)      //Triaxial Spheroid, 
        variable Q, radius, par1,par2,par3,par4,par5    
        //based on Triaxial Spherdoid from NIST SANS tools, 
        //ftp.ncnr.nist.gov/pub/sans/kline/Download/SANS_Model_Docs_v4.10.pdf           
        //the shape is elllipsoid with 3 different radii : dimensions R, R1, R2, R<R1<R2. This is important!!!          
        //                              note Rg = (R^2+R1^2+R2^2)/5             
        //assumptions:  Par1 is ratio of R1/R, requirement: Par1>1
        //                                      Par2 is R2/R,  requirements:  Par2>1, Par2>Par1
        //Par3-Par5 are not used 
        if(Par2<1 || Par1<1 || Par2<Par1)
                abort "Parameters in TriaxSpheroid form factor are  not correct"
        endif
        variable aa,bb,cc
        aa=radius
        bb=Par1*radius
        cc=Par2*radius
        return sqrt(TriaxSpheroidIntgOut(Q,aa,bb,cc))           //TriaxSpheroidIntgOut return F^2, code expect F. 
end
//****************************************************************************************************
Function TriaxSpheroidVolume(radius, par1,par2,par3,par4,par5)
        variable radius, par1,par2,par3,par4,par5       
        //based on Triaxial Spherdoid from NIST SANS tools, 
        //ftp://ftp.ncnr.nist.gov/pub/sans/kline/Download/SANS_Model_Docs_v4.10.pdf                                                             
        variable aa,bb,cc
        aa=radius
        bb=Par1*radius
        cc=Par2*radius
        return 4*pi*aa*bb*cc/3
end
//****************************************************************************************************
//work functions, do not change 
Function TriaxSpheroidIntgOut(qq,aa,bb,cc)
        Variable qq,aa,bb,cc            
        make/Free TempWave
        SetScale/I x, 0, 1,  TempWave
        multithread TempWave = TriaxSpheroidIntgInside(qq,aa,bb,cc,x)
        return area(TempWave)   
end
//****************************************************************************************************
threadsafe Function TriaxSpheroidIntgInside(qq,aa,bb,cc,dy)
        Variable qq,aa,bb,cc,dy         
        make/Free TempWave
        SetScale/I x, 0, 1,  TempWave
        TempWave = TriaxSpheroidInside(qq,aa,bb,cc,x,dy)
        return area(TempWave)   
end
//****************************************************************************************************
threadsafe Function TriaxSpheroidInside(qq,aa,bb,cc,dx,dy)
        Variable qq,aa,bb,cc,dx,dy
        //aa, bb, cc are simply dimensions
        //qq is Q
        //dx, dy are integrants. 
        Variable val,arg
        arg = aa*aa*cos(pi*dx/2)*cos(pi*dx/2)
        arg += bb*bb*sin(pi*dx/2)*sin(pi*dx/2)*(1-dy*dy)
        arg += cc*cc*dy*dy
        arg = qq*sqrt(arg)
        if(arg == 0)
                val = 1
        else
                val = 9*((sin(arg) - arg*cos(arg))/arg^3 )^2
        endif
        return(val)
end
//****************************************************************************************************