reverse left-right, documentation

Author: go-ski

R/comm.chunk.r

@@ -1,27 +1,31 @@
 #' comm.chunk
 #'
-#' Given a total number of items comm.chunk splits the number into equal
-#' chunks. Warious options are possible when the number does not split evenly
-#' into chunks.
+#' Given a total number of items, comm.chunk splits the number into
+#' chunks. Tailored especially for situations in SPMD style
+#' programming. Warious options are possible when the number does not
+#' split evenly into chunks. The output form can be either a number or
+#' a vector of items.
 #'
 #' @param N
-#' The number of items to split into equal chunks.
+#' The number of items to split into chunks.
 #' @param form
-#' Output a chunk as a sigle "number", as a "vector" of items from 1:N, or as
-#' an "IOpair" giving offsets and lengths in a file.
+#' Output a chunk as a single "number", as a "vector" of contiguous
+#' items from 1:N, or as an "iopair" giving offset and length in a
+#' file.
 #' @param type
-#' Either "balance" the chunks so they differ by no more than 1 item or force
-#' as many as possible to be "equal" with possibly one or more smaller or even
-#' zero size chunks.
+#' Either "balance" the chunks so they differ by no more than 1 item (used most
+#' frequently for best balance) or force as many as possible to be "equal" with
+#' possibly one or more smaller or even zero size chunks (required by ScaLAPACK's
+#' block-cyclic layouts).
 #' @param lo.side
-#' If exact balance is not possible, put the lower chunks on the "left" or on
-#' the "right".
+#' If exact balance is not possible, put the smaller chunks on the "left" (low ranks)
+#' or on the "right" (high ranks).
 #' @param all.rank
 #' FALSE returns only the chunk output for rank r. TRUE returns a vector of
 #' length p (when form="number"), and a list of length p (when form="vector")
 #' each containing the output for the corresponding rank.
 #' @param p
-#' The number of chunks (defaults to comm.size()).
+#' The number of chunks (processors) Defaults to comm.size().
 #' @param rank
 #' The rank of returned chunk (defaults to comm.rank()). Note that ranks are
 #' numbered from 0 to p-1, whereas the list elements for all.rank=TRUE are
@@ -34,8 +38,8 @@
 #'
 #' @examples
 #' ## Note that the p and rank parameters are provided by comm.size() and
-#' ## comm.rank(), respectively, when running in parallel with pbdMPI and
-#' ## need not be specified.
+#' ## comm.rank(), respectively, when running SPMD in parallel. Normally, they
+#' ## are not specified unless testing in serial mode.
 #' library(pbdIO)
 #'
 #' comm.chunk(16, all.rank=TRUE, p=5)
@@ -44,18 +48,18 @@
 #' comm.chunk(16, p=5, rank=0)
 #'
 #' @export
-comm.chunk <- function(N, form="number", type="balance", lo.side="left",
+comm.chunk <- function(N, form="number", type="balance", lo.side="right",
                        all.rank=FALSE, p=comm.size(), rank=comm.rank()) {
 
-    form <- comm.match.arg(tolower(form), c("number", "vector", "IOpair"))
-    type <- comm.match.arg(tolower(type), c("balance", "equal"))
-    lo.side <- comm.match.arg(tolower(lo.side), c("left", "right"))
+    form <- comm.match.arg(form, c("number", "vector", "iopair"))
+    type <- comm.match.arg(type, c("balance", "equal", "ldim", "bldim"))
+    lo.side <- comm.match.arg(lo.side, c("right", "left"))
     if (!is.logical(all.rank) || length(all.rank) != 1 || is.na(all.rank))
         comm.stop("argument 'all.rank' must be a bool")
     if (!is.numeric(p) || p < 1)
         comm.stop("argument 'p' must be a positive integer")
-    if (!is.numeric(rank) || rank < 0 || rank >= comm.size())
-        comm.stop("argument 'rank' must be an integer from 0 to comm.size()-1")
+    if (!is.numeric(rank) || rank < 0 || rank >= p)
+        comm.stop("argument 'rank' must be an integer from 0 to p-1")
 
     p <- as.integer(p)
     rank <- as.integer(rank)
@@ -75,7 +79,7 @@ comm.chunk <- function(N, form="number", type="balance", lo.side="left",
             } else if(lo.side == "left") {
                 items[(p - rem + 1):p] <- base + 1
             }
-        } else if(type == "equal") {
+        } else if(type == "equal" | type == "ldim") { ## fix for bldim!!!
             items <- items + 1
             rem <- p*(base + 1) - N
             if(lo.side == "right") {
@@ -111,7 +115,7 @@ comm.chunk <- function(N, form="number", type="balance", lo.side="left",
         if(all.rank) ret <- lapply(1:length(items_base),
                      function(i) lapply(items, seq_len)[[i]] + items_base[i])
         else ret <- items_base[rank + 1] + seq_len(items[rank + 1])
-    } else if(form == "IOpair") {
+    } else if(form == "iopair") {
         offset <- c(0, cumsum(items)[-p])
         ret <- c(offset[rank + 1], items[rank + 1])
     } else ret <- NULL

demo/matrix.r

@@ -89,7 +89,9 @@ comm.print(names(beta))
 a <- deltime(a, "lm.fit:")
 
 xtx <- crossprod(xd_mm)
+print(xtx)
 xty <- crossprod(xd_mm, yd)
+print(xty)
 
 beta.coef <- solve(xtx, xty)
 beta <- as.matrix(beta.coef)