Changeset 4329539 in sasmodels

Timestamp:

Mar 5, 2017 4:23:38 PM (7 years ago)

Author:

butler

Branches:

master, core_shell_microgels, costrafo411, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests

Children:

bb73096

Parents:

e1aa129

Message:

add comments to rpa c code to help code readability. Addresses ticket
#593

File:

• sasmodels/models/rpa.c (modified) (8 diffs)

sasmodels/models/rpa.c

@@ -39 +39 @@
   double S31,S32,S33,S34,S41,S42,S43,S44;
   double Lad,Lbd,Lcd,Nav,Intg;
-
+  
+  // Set values for non existent parameters (eg. no A or B in case 0 and 1 etc)
   //icase was shifted to N-1 from the original code
   if (icase <= 1){
@@ -57 +58 @@
     Kab = Kac = Kad = -0.0004;
   }
-
+ 
+  //set up values for cross terms in case of block copolymers (1,3,4,6,7,8,9)
   Nab=sqrt(N[0]*N[1]);
   Nac=sqrt(N[0]*N[2]);
@@ -79 +81 @@
   Phicd=sqrt(Phi[2]*Phi[3]);
 
+  // Calculate Q^2 * Rg^2 for each homopolymer assuming random walk 
   Xa=q*q*b[0]*b[0]*N[0]/6.0;
   Xb=q*q*b[1]*b[1]*N[1]/6.0;
@@ -84 +87 @@
   Xd=q*q*b[3]*b[3]*N[3]/6.0;
 
-  Paa=2.0*(exp(-Xa)-1.0+Xa)/(Xa*Xa);
-  S0aa=N[0]*Phi[0]*v[0]*Paa;
-  Pab=((1.0-exp(-Xa))/Xa)*((1.0-exp(-Xb))/Xb);
+  //calculate all partial structure factors Pij and normalize n^2
+  Paa=2.0*(exp(-Xa)-1.0+Xa)/(Xa*Xa); // free A chain form factor
+  S0aa=N[0]*Phi[0]*v[0]*Paa; // Phi * Vp * P(Q)= I(Q0)/delRho^2
+  Pab=((1.0-exp(-Xa))/Xa)*((1.0-exp(-Xb))/Xb); //AB diblock (anchored Paa * anchored Pbb) partial form factor
   S0ab=(Phiab*vab*Nab)*Pab;
-  Pac=((1.0-exp(-Xa))/Xa)*exp(-Xb)*((1.0-exp(-Xc))/Xc);
+  Pac=((1.0-exp(-Xa))/Xa)*exp(-Xb)*((1.0-exp(-Xc))/Xc); //ABC triblock AC partial form factor
   S0ac=(Phiac*vac*Nac)*Pac;
-  Pad=((1.0-exp(-Xa))/Xa)*exp(-Xb-Xc)*((1.0-exp(-Xd))/Xd);
+  Pad=((1.0-exp(-Xa))/Xa)*exp(-Xb-Xc)*((1.0-exp(-Xd))/Xd); //ABCD four block
   S0ad=(Phiad*vad*Nad)*Pad;
 
   S0ba=S0ab;
-  Pbb=2.0*(exp(-Xb)-1.0+Xb)/(Xb*Xb);
+  Pbb=2.0*(exp(-Xb)-1.0+Xb)/(Xb*Xb); // free B chain
   S0bb=N[1]*Phi[1]*v[1]*Pbb;
-  Pbc=((1.0-exp(-Xb))/Xb)*((1.0-exp(-Xc))/Xc);
+  Pbc=((1.0-exp(-Xb))/Xb)*((1.0-exp(-Xc))/Xc); // BC diblock
   S0bc=(Phibc*vbc*Nbc)*Pbc;
-  Pbd=((1.0-exp(-Xb))/Xb)*exp(-Xc)*((1.0-exp(-Xd))/Xd);
+  Pbd=((1.0-exp(-Xb))/Xb)*exp(-Xc)*((1.0-exp(-Xd))/Xd); // BCD triblock
   S0bd=(Phibd*vbd*Nbd)*Pbd;
 
   S0ca=S0ac;
   S0cb=S0bc;
-  Pcc=2.0*(exp(-Xc)-1.0+Xc)/(Xc*Xc);
+  Pcc=2.0*(exp(-Xc)-1.0+Xc)/(Xc*Xc); // Free C chain
   S0cc=N[2]*Phi[2]*v[2]*Pcc;
-  Pcd=((1.0-exp(-Xc))/Xc)*((1.0-exp(-Xd))/Xd);
+  Pcd=((1.0-exp(-Xc))/Xc)*((1.0-exp(-Xd))/Xd); // CD diblock
   S0cd=(Phicd*vcd*Ncd)*Pcd;
 
@@ -111 +115 @@
   S0db=S0bd;
   S0dc=S0cd;
-  Pdd=2.0*(exp(-Xd)-1.0+Xd)/(Xd*Xd);
+  Pdd=2.0*(exp(-Xd)-1.0+Xd)/(Xd*Xd); // free D chain
   S0dd=N[3]*Phi[3]*v[3]*Pdd;
+
+  // Reset all unused partial structure factors to 0 (depends on case)
   //icase was shifted to N-1 from the original code
   switch(icase){
@@ -193 +199 @@
   S0dc=S0cd;
 
+  // self chi parameter is 0 ... of course
   Kaa=0.0;
   Kbb=0.0;
@@ -243 +250 @@
   ZZ=S0ad*(T11*S0ad+T12*S0bd+T13*S0cd)+S0bd*(T21*S0ad+T22*S0bd+T23*S0cd)+S0cd*(T31*S0ad+T32*S0bd+T33*S0cd);
 
+  // D is considered the matrix or background component so enters here
   m=1.0/(S0dd-ZZ);
 
@@ -297 +305 @@
   S44=S11+S22+S33+2.0*S12+2.0*S13+2.0*S23;
 
+  //calculate contrast where L[i] is the scattering length of i and D is the matrix
+  //need to verify why the sqrt of Nav rather than just Nav (assuming v is molar volume)
   Nav=6.022045e+23;
   Lad=(L[0]/v[0]-L[3]/v[3])*sqrt(Nav);