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[Bioc-devel] RFC: xy2i and i2xy in *cdf packages

I found an interesting "trick" adopted within the package mtachprobes
to solve this problem...
i.e. obtaining chip dimensions information from current versions of
CDF packages.

Within the package "matchprobes" there's a function named
".lgExtraParanoia"

If you read this function code you can find the following lines:
#############
tab = table(mm1 - pm1)
sizex = as.numeric(names(tab))[max(tab) == tab]
pm2 = pt$y * sizex + pt$x + 1
#############

"mm1" is a vector containing MM probes indexes (obtained from CDF package)
"pm1" is a vector containing PM probes indexes (obtained from CDF package)
Then chip dimension (i.e. "sizex") is obtained as the maximum difference between
MM and PM probes indexes. This is based on the assumption that PM and
MM probe are usually next to each other on the chip
at same x coordinate and at adjacent y coordinates.
The last line is equal to function "xy2i()" since "pt" is a data.frame
containing probe sequences information
and columns x and y (i.e. vectors "pt$x" and "pt$y") contain xy probes
coordinates



However I agree with the fact that this could not be the final solution
and that having dim environment accessible within CDF packages is a
better solution.

Best,
Francesco