CA SRI - Correspondence Analysis - Reconstitute Importance images

PURPOSE

Compute importance image for a selected factor from CORAN.

SEE ALSO

CA S	[Correspondence Analysis - Solution]
CA SM	[Correspondence Analysis - Show Map & Eigen Values]
CA SRD	[Correspondence Analysis - Reconstitute Differential images]

USAGE

.OPERATION: CA SRI

.CORAN FILE PREFIX: coran_t_
[Enter the prefix for the files created in 'CA S'.]

.ENTER FILE NUMBERS TO BE USED (EG. 1-8,12-22,55): 1-80,90-95
[Numbers are consecutive, and refer to the sequence of files specified in 'CA S'. ]

.ENTER FACTORS TO BE USED: 2-4
[Enter the factors to be used for image reconstitution. Note that the numbers have to be less that the number of images and less or equal to the number used in 'CA S'.]

.OUTPUT FILE TEMPLATE: SRI_****
[Enter the prefix for the files created here.]

NOTES

1. For a detailed explanation of concepts used for CORAN see: J.P. Bretaudiere and J. Frank (1986) J. Microscopy 144:1-14. Importance images are defined in J. Frank and M. van Heel (1982) J. Mol. Biol. 161:133-137.

2. The "importance image" obtained by using 'CA SRI' has both positive and negative values. To obtain the more familiar pair of complementary positive-definite importance images used in the earlier literature (e.g. Frank et al., 1982), follow this operation by 'TH' (threshold), specifying '0' as the lower or upper threshold, respectively. Then invert contrast of the thresholded image.

SUBROUTINES

JPMSK2

CALLER

UTIL1