[ccp4bb]: sigmaa and HL coefficients

[ernst@UTBC08.CM.UTEXAS.EDU]

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Has anyone had experience with the sigmaa  <combine mir2> option?

I had 4 weak derivatives on which i individually used solve and resolve
and then tried to combine the resolve A,B,C,D  coefs in pairs and
the resulting coefs into a single set of HL coefs.  while the
(phase,fom) from the initial pairs seemed reasonable the
ABCD coefs were definitely not reasonable and the 2nd combination
(of the pair of pairs) gave garbage for both phase and fom.

using the same data with CNS produced HL coef's such that
A1 + A2 + A3 + A4 = SUMA which was not the case for sigmaa

I have attempted to  make an understandable table for a single HKL
for both sigmaa and cns as follows:

the column labeled CNS lists all 4 derivs (SE,PC,DMP,E6) and at the bottom
the CNS combined values.
                                                                                          the righthand column also lists the 4 derivs with individual phase & fom
and then the pair-wise
<phase,fom> and (A,B,C,D) from sigmaa.

the middle column also lists the pairwise result and then the
result of the combining the pair-wise coefs.

the CNS final phase is very nearly the mean and middle value of the
indivdual phases (reasonable) ; the sigma phase is in the opposite
quadrant.

the CNS A,B,C,D values are the sum of the respective individual values.
on the other hand sigmaa has set A&B = 0 for all of the combinations
while C&D are the sums of individual C&D's.


this is from SIGMAA version 4.0 15/12/99
                                                                                 
     CNS               sigmaa(pairs of pairs)       sigmaa (pairs)
se+pcmb+demp+emts
INDEX     1 1 9
FSE       841.700                                     semet+pcmb3
SSE       7.280
PASE     -19.873                                       -19.87
PBSE     -3.861                                        -3.86
PCSE     -1.196                                        -1.20
PDSE     -0.405                                        -0.40
                                                     191.48 0.97
FPC       1151.200
SFPC      6.540
PAPC     -2.450          0.00                          -2.45
PBPC     -3.186          0.00                          -3.19
PCPC      2.126          1.81                           2.13
PDPC      1.533          2.60                           1.53
                                                     208.02 0.96
                                                    <198.99 0.98>
                                                 (0.00 0.00 1.81 2.60)
FDMP      1210.7
SFDMP     9.920                                      demp+emts6
PADMP    -1.993                                        -1.99
PBDMP    -3.384                                        -3.38
PCDMP     1.735                                        1.74
PDDMP     2.749                                        2.75
                                                     216.12 0.97

FE6       1141.800
SFE6      9.860
PAE6     -9.721           0.00                         -9.72
PBE6     -11.829          0.00                        -11.83
PCE6      0.071           0.93                          0.07
PDE6     -0.148           1.13                         -0.15
                                                    230.30 0.97
                                                    <223.11 0.98>
                                                (0.00 0.00 0.93 1.13)
                      se+pcmb+demp+emts
PA_CMB4  -34.037           0.00
PB_CMB4  -22.260           0.00
PC_CMB4   2.736            2.74
PD_CMB4   3.729            3.73
FOBCMB4   841.700
phaseCMB4 211.249          85.90
FOMCMB4   0.991            0.00
                                                                                            
Steve Ernst
Univ. of Texas
Dept of Chemistry & Biochemistry