diff --git a/collects/racket/place/distributed/rmpi.rkt b/collects/racket/place/distributed/rmpi.rkt
index c634545faa..bc6b0235c4 100644
--- a/collects/racket/place/distributed/rmpi.rkt
+++ b/collects/racket/place/distributed/rmpi.rkt
@@ -13,7 +13,9 @@
          rmpi-recv
          rmpi-broadcast
          rmpi-reduce
+         rmpi-gather
          rmpi-allreduce
+         rmpi-allgather
          rmpi-alltoall
          rmpi-alltoallv
          rmpi-barrier
@@ -77,7 +79,7 @@
                  (cond 
                    [(not (= 0 (bitwise-and id round)))
                     (define peer-id (- id round))
-                    (define real-peer-id (modulo (+ peer-id offset) cnt))
+                    (define real-peer-id (modulo (+ peer-id src) cnt))
                     ;(printf "BRECV ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
                     (place-channel-get (vector-ref chs real-peer-id))
                     ]
@@ -85,7 +87,7 @@
                     (define peer-id (+ id round))
                     (cond
                       [(< peer-id cnt)
-                        (define real-peer-id (modulo (+ peer-id offset) cnt))
+                        (define real-peer-id (modulo (+ peer-id src) cnt))
                         ;(printf "BSEND ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
                         (place-channel-put (vector-ref chs real-peer-id) val)])
                     val])]
@@ -125,6 +127,7 @@
 
   (define offset (- cnt dest))
   (define (convert v) (modulo (+ v offset) cnt))
+  (define (pconvert v) (modulo (+ v dest) cnt))
   (define id (convert real-id))
   (let loop ([i i]
              [val val])
@@ -138,8 +141,8 @@
              (cond 
                [(not (= 0 (bitwise-and id round)))
                 (define peer-id (- id round))
-                (define real-peer-id (convert peer-id))
-                ;(printf/f "SEND ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
+                (define real-peer-id (pconvert peer-id))
+                ;(printf/f "SEND ROUND ~a RID ~a RPID ~a ID ~a PID ~a OFF ~a\n" round real-id real-peer-id id peer-id offset)
                 (place-channel-put (vector-ref chs real-peer-id) val)
                 val
                 ]
@@ -147,23 +150,100 @@
                 (define peer-id (+ id round))
                 (cond
                   [(< peer-id cnt)
-                    (define real-peer-id (convert peer-id))
-                    ;(printf/f "RECV ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
+                    (define real-peer-id (pconvert peer-id))
+                    ;(printf/f "RECV ROUND ~a RID ~a RPID ~a ID ~a PID ~a OFF ~a\n" round real-id real-peer-id id peer-id offset)
                     (define recv-val (place-channel-get (vector-ref chs real-peer-id)))
                     ;(printf/f "RECVVAL ~a ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset recv-val)
                     (fancy-reducer op recv-val val)]
                   [else val])])]))]
       [else val])))
 
+(define (rmpi-gather comm dest val)
+  (match-define (rmpi-comm real-id cnt chs) comm)
+  (define i
+    (let loop ([i 0])
+      (if (>= (arithmetic-shift 1 i) cnt)
+        i
+        (loop (add1 i)))))
+
+
+  (define offset (- cnt dest))
+  (define (convert v) (modulo (+ v offset) cnt))
+  (define (pconvert v) (modulo (+ v dest) cnt))
+  (define id (convert real-id))
+  (define retval
+    (let loop ([i i]
+               [val (vector val)])
+      (cond
+        [(> i 0)
+         (define round (arithmetic-shift 1 (sub1 i)))
+         (loop 
+           (sub1 i)
+           (cond
+             [(< id (arithmetic-shift round 1))
+               (cond 
+                 [(not (= 0 (bitwise-and id round)))
+                  (define peer-id (- id round))
+                  (define real-peer-id (pconvert peer-id))
+                  ;(printf/f "SEND ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
+                  (place-channel-put (vector-ref chs real-peer-id) val)
+                  val
+                  ]
+                 [else
+                  (define peer-id (+ id round))
+                  (cond
+                    [(< peer-id cnt)
+                      (define real-peer-id (pconvert peer-id))
+                      ;(printf/f "RECV ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset)
+                      (define recv-val (place-channel-get (vector-ref chs real-peer-id)))
+                      ;(printf/f "RECVVAL ~a ~a ~a ~a ~a ~a ~a\n" round real-id id peer-id real-peer-id offset recv-val)
+                      (define (order real-id val real-peer-id pval)
+                        (define vl (vector-length val))
+                        (define pvl (vector-length pval))
+                        (define new-val (make-vector (+ vl pvl)))
+                        (define v1 (if (< real-id real-peer-id) val pval))
+                        (define v2 (if (< real-id real-peer-id) pval val))
+                        (define v1l (if (< real-id real-peer-id) vl pvl))
+                        (define v2l (if (< real-id real-peer-id) pvl vl))
+                        (let loop ([i 0]
+                                   [j 0]
+                                   [ii 0])
+                          (cond 
+                            [(< i v1l)
+                              (vector-set! new-val ii (vector-ref v1 i))
+                              (cond 
+                                [(< j v2l)
+                                 (vector-set! new-val (+ 1 ii) (vector-ref v2 j))
+                                 (loop (+ 1 i) (+ 1 j) (+ 2 ii))]
+                                [else
+                                 (loop (+ 1 i) j (+ 1 ii))])]
+                             [(< j v2l)
+                              (vector-set! new-val (+ 1 ii) (vector-ref v2 j))
+                              (loop i (+ 1 j) (+ 1 ii))]
+                             [else
+                               new-val])))
+                      (order id val peer-id recv-val)]
+                    [else val])])]))]
+        [else val])))
+  (cond
+    [(and (not (zero? dest)) (= real-id dest))
+     (for/vector #:length cnt ([i cnt])
+       (vector-ref retval (modulo (+ i offset) cnt)))]
+    [else retval]))
+
+
 (define (rmpi-barrier comm)
   (rmpi-reduce comm 0 + 1)
   (rmpi-broadcast comm 0 1))
 
 (define (rmpi-allreduce comm op val)
-
   (define rv (rmpi-reduce comm 0 op val))
   (rmpi-broadcast comm 0 rv))
 
+(define (rmpi-allgather comm op val)
+  (define rv (rmpi-gather comm 0 val))
+  (rmpi-broadcast comm 0 rv))
+
 (define (partit num cnt id)
   (define-values (quo rem) (quotient/remainder num cnt))
   (values (+ (* id quo) (if (< id rem) id rem))