I am trying to run OLIGOMER to test the ratios between more than 2 (but less than 10) pdb files, which all have the same mass and contrast,they only differ in conformation. I would like to enforce that each pdb file retains the same volume (or number) fraction.

Therefore, I run FFMAKER with the following constraint file (for example for 3 components):

the header of the dat file coming from FFMAKER looks like:Volume Fraction Relation Coefficients: 1.0 -1.0 1.0

However, this results in the following once I run OLIGOMER (with constant)FormFactor file for OLIGOMER created from: toFFStructure1.dat toFFoStructure2.dat toFFStructure3.dat

Contrasts: 0.10000E+01 0.10000E+01 0.10000E+01

VolumeFractionConstrains: 1.0000 -1.0000 1.0000

0.0000000E+00 0.1253000E+08 0.1392200E+08 0.1355800E+08

0.1023600E-02 0.1252400E+08 0.1391100E+08 0.1354700E+08

This happens on both ATSAS-2.7.2 and ATSAS-2.8.3Using constant as additional component

experimental.dat 62.86 3311 41.50 0.000+-0.000 0.488+-0.002 0.488+-0.002 0.024+-0.000

Two of the 3 pdbs do indeed have the same population, but the third one is set to zero. How do I enforce A=B=C...=N? I have tried setting the volume fractions to, say 0.33 each, but this makes no difference. Is there a way to check the scattering for N components when each component makes up 1/N of the sample?

Many thanks!