TensorMath.lua: zero init result tensor

A function like `torch.mm` stores its output into a result tensor (res)
and uses the `addmm` function behind the scenes. `addmm` performs multi-
plications like res = beta x res + alpha x sum with beta=0 and alpha=1
here. If res is not initialized NaN values could occur resulting on NaN
output values.

The same applies for `torch.bmm` and `torch.mv`.

1 files changed, 21 insertions, 0 deletions

diff --git a/TensorMath.lua b/TensorMath.lua
index ac52dc6..6acb6b8 100644
--- a/TensorMath.lua
+++ b/TensorMath.lua
@@ -314,6 +314,13 @@ for _,Tensor in ipairs({"ByteTensor", "CharTensor",
                         string.format("TH%s_resize1d(%s, %s->size[0]);", Tensor, arg:carg(), arg.args[5]:carg())
                      }, '\n')
                end,
+          precall=function(arg)
+                  return table.concat(
+                     {
+                        string.format("TH%s_zero(%s);", Tensor, arg:carg()),
+                        arg.__metatable.precall(arg)
+                     }, '\n')
+               end,
        },
          {name=real, default=0, invisible=true},
          {name=Tensor, default=1, invisible=true},
@@ -332,6 +339,13 @@ for _,Tensor in ipairs({"ByteTensor", "CharTensor",
                         string.format("TH%s_resize2d(%s, %s->size[0], %s->size[1]);", Tensor, arg:carg(), arg.args[5]:carg(), arg.args[6]:carg())
                      }, '\n')
                end,
+          precall=function(arg)
+                  return table.concat(
+                     {
+                        string.format("TH%s_zero(%s);", Tensor, arg:carg()),
+                        arg.__metatable.precall(arg)
+                     }, '\n')
+               end,
        },
          {name=real, default=0, invisible=true},
          {name=Tensor, default=1, invisible=true},
@@ -351,6 +365,13 @@ for _,Tensor in ipairs({"ByteTensor", "CharTensor",
                                       Tensor, arg:carg(), arg.args[5]:carg(), arg.args[5]:carg(), arg.args[6]:carg())
                      }, '\n')
                end,
+          precall=function(arg)
+                  return table.concat(
+                     {
+                        string.format("TH%s_zero(%s);", Tensor, arg:carg()),
+                        arg.__metatable.precall(arg)
+                     }, '\n')
+               end,
        },
          {name=real, default=0, invisible=true},
          {name=Tensor, default=1, invisible=true},