1 files changed, 108 insertions, 0 deletions
diff --git a/nerv/io/seq_buffer.lua b/nerv/io/seq_buffer.lua
index e69de29..029e7b8 100644
--- a/nerv/io/seq_buffer.lua
+++ b/nerv/io/seq_buffer.lua
@@ -0,0 +1,108 @@
+local SeqBuffer = nerv.class('nerv.SeqBuffer', 'nerv.DataBuffer')
+
+function SeqBuffer:__init(global_conf, buffer_conf)
+    self.gconf = global_conf
+
+    self.batch_size = buffer_conf.batch_size
+    self.chunk_size = buffer_conf.chunk_size
+    self.readers = {}
+    for _, v in ipairs(buffer_conf.readers) do
+        table.insert(self.readers, v.reader)
+    end
+    self.nn_act_default = buffer_conf.nn_act_default
+    if self.nn_act_default == nil then
+        self.nn_act_default = 0
+    end
+
+    self.mat_type = self.gconf.mmat_type
+    self.queue = {}
+    self.head = 1
+    self.tail = 0
+end
+
+function SeqBuffer:new_mini_batch()
+    local res = {}
+    res.data = {}
+    res.new_seq = {}
+    res.seq_length = {}
+    for i = 1, self.batch_size do
+        res.seq_length[i] = 0
+    end
+    return res
+end
+
+function SeqBuffer:saturate(batch)
+    if self.queue[self.head] ~= nil and self.queue[self.head].seq_length[batch] ~= 0 then
+        return true
+    end
+    local data = {}
+    local drow = nil
+    for i = 1, #self.readers do
+        local tmp = self.readers[i]:get_data()
+        if tmp == nil then
+            return false
+        end
+        for id, d in pairs(tmp) do
+            if drow == nil then
+                drow = d:nrow()
+            elseif d:nrow() ~= drow then
+                nerv.error('readers provides with inconsistent rows of data')
+            end
+            data[id] = d
+        end
+    end
+    local offset = 0
+    local head = self.head
+    while offset < drow do
+        local last = math.min(offset + self.chunk_size, drow)
+        if head > self.tail then
+            self.tail = self.tail + 1
+            self.queue[self.tail] = self:new_mini_batch()
+        end
+        self.queue[head].seq_length[batch] = last - offset
+        if offset == 0 then
+            table.insert(self.queue[head].new_seq, batch)
+        end
+        local mini_batch = self.queue[head].data
+        for id, d in pairs(data) do
+            if mini_batch[id] == nil then
+                mini_batch[id] = {}
+            end
+            local tmp = mini_batch[id]
+            for i = offset + 1, last do
+                local chunk = i - offset
+                if tmp[chunk] == nil then
+                    tmp[chunk] = self.mat_type(self.batch_size, d:ncol())
+                    tmp[chunk]:fill(self.nn_act_default)
+                end
+                tmp[chunk]:copy_from(d, i - 1, i, batch - 1)
+            end
+        end
+        head = head + 1
+        offset = last
+    end
+    return true
+end
+
+function SeqBuffer:get_data()
+    local has_data = false
+    for i = 1, self.batch_size do
+        if self:saturate(i) then
+            has_data = true
+        end
+    end
+    if not has_data then
+        return nil
+    end
+    local res = self.queue[self.head]
+    self.queue[self.head] = nil
+    self.head = self.head + 1
+    if not self.gconf.use_cpu then
+        for id, d in pairs(res.data) do
+            for i = 1, #d do
+                d[i] = self.gconf.cumat_type.new_from_host(d[i])
+            end
+        end
+    end
+    return res
+end