Translated ind2subv() (#3)

R/ind2subv.R

@@ -1,38 +1,37 @@
-ind2subv <- function(siz, ndx) stop("Needs translation")
-# function sub = ind2subv(siz, ndx)
-# % IND2SUBV Like the built-in ind2sub, but returns the answer as a row vector.
-# % sub = ind2subv(siz, ndx)
-# %
-# % siz and ndx can be row or column vectors.
-# % sub will be of size length(ndx) * length(siz).
-# %
-# % Example
-# % ind2subv([2 2 2], 1:8) returns
-# %  [1 1 1
-# %   2 1 1
-# %   ...
-# %   2 2 2]
-# % That is, the leftmost digit toggle fastest.
-# %
-# % See also SUBV2IND
+ind2subv <- function(siz, ndx) {
+  #  IND2SUBV Like the built - in ind2sub, but returns the answer as a row vector.
+  #  sub <- ind2subv(siz, ndx)
+  #  siz and ndx can be row or column vectors.
+  #  sub will be of size length(ndx) * length(siz).
+  #  Example
+  #  ind2subv([2 2 2], 1:8) returns
+  #   [1 1 1
+  #    2 1 1
+  #     ...
+  #    2 2 2]
+  #  That is, the leftmost digit toggle fastest.
+  #
+  #  See also SUBV2IND
 
-# n = length(siz);
+  n <- length(siz)
 
-# if n==0
-#   sub = ndx;
-#   return;
-# end
+  if (n == 0) {
+    sub <- ndx
+    return(sub)
+  }
 
-# if all(siz==2)
-#   sub = dec2bitv(ndx-1, n);
-#   sub = sub(:,n:-1:1)+1;
-#   return;
-# end
+  if (all(siz == 2)) {
+    sub <- dec2bitv(ndx - 1, n)
+    sub <- sub[, seq(n, 1, - 1)] + 1
+    return(sub)
+  }
 
-# cp = [1 cumprod(siz(:)')];
-# ndx = ndx(:) - 1;
-# sub = zeros(length(ndx), n);
-# for i = n:-1:1 % i'th digit
-#   sub(:,i) = floor(ndx/cp(i))+1;
-#   ndx = rem(ndx,cp(i));
-# end
+  cp <- c(1, cumprod(t(siz[])))
+  ndx <- ndx[] - 1
+  sub <- zeros(length(ndx), n)
+  for (i in seq(n, 1, -1)) {# i'th digit
+    sub[, i] <- floor(ndx / cp[i]) + 1
+    ndx <- ndx %% cp(i)
+  }
+  return(sub)
+}