FlashMatrix user guide fixes

[disa-mhembere]

Issues I couldn't resolve:

• fm.seq.matrix example is confusing. I expected numbers 1:20 ??

as.matrix(fm.seq.matrix(0, 20, 10, 2))
          [,1]     [,2]
 [1,] 0.000000 10.52632
 [2,] 1.052632 11.57895
 [3,] 2.105263 12.63158
 [4,] 3.157895 13.68421
 [5,] 4.210526 14.73684
 [6,] 5.263158 15.78947
 [7,] 6.315789 16.84211
 [8,] 7.368421 17.89474
 [9,] 8.421053 18.94737
[10,] 9.473684 20.00000

• Need a way to link to sections of the same file like anchor. Tried unsuccessfully to do this. To get rid of statements like "see below .."
• FWIW the Euclidean distance is the sqrt of that expression in fm.bo.euclidean
• Examples like "Example 1: compute m1 + m2" might be better if we define m1 and m2 first so people can try them. I'm not sure what I did wrong with this:

require(FlashR)
m1 <- fm.runif(10)
m2 <- fm.runif(10)
fm.mapply2(m1, m2, "+")

Error in (function (classes, fdef, mtable)  :
  unable to find an inherited method for function ‘fm.mapply2’ for signature ‘"fmV", "fmV", "character", "missing"’

• "fm.groupby outputs a matrix with the number of rows equal to the maximal number of levels ...". What is a level here? The number of groups?

• An example of how fm.set.cached could fix a potentially slow operation might be necessary. I think it's a big enough deal.

[zheng-da]

like fm.seq.int, both from and to should be included in the sequence. fm.seq.matrix didn't handle it correctly. I have fixed the problem. the example in the user guide was based on the original implementation.

[zheng-da]

the way of creating links to sections work.