replace the theano flags warn.old_bug_default by warn.ignore_bug_before and doc…

doc/install.txt

@@ -94,6 +94,32 @@ In csh:
 
     setenv PYTHONPATH <path to Theano's parent dir>/Theano:$PYTHONPATH
 
+Testing your installation
+---------------------------
+
+Once you have completed these steps, you should run the theano test suite like this:
+
+.. code-block:: bash
+
+    cd Theano
+    THEANO_FLAGS=warn.ignore_bug_before=all nosetests #execute all the tests
+
+
+THEANO_FLAGS is an environment variable that define Theano flags (:ref:`libdoc_config`).
+For Windows user, you can remove it or see the doc to know how to configure them differently.
+
+All tests should pass except the test marked as KnownFailureTest. If some test 
+fails on your machine, you are encouraged to tell us what went wrong on the 
+``theano-users@googlegroups.com`` mailing list.
+
+.. note::
+
+    `warn.ignore_bug_before=all` remove warning that you don't need to see here.
+    It is also recommended for new user to put this flag to a different value 
+    into their .theanorc file. Go 
+    `here <file:///u/bastienf/repos/Theano/html/library/config.html?libdoc-config#config.warn.ignore_bug_before>`__
+    for detail.
+
 Troubleshooting: Make sure you have a BLAS library
 -----------------------------------------------------
 
@@ -150,20 +176,6 @@ Here are some different way to configure BLAS:
     arguments to gcc, but the problem is not fixed yet.
 
 
-Testing your installation
----------------------------
-
-Once you have completed these steps, you should run the theano test suite like this:
-
-.. code-block:: bash
-
-    cd Theano
-    nosetests #execute all the tests
-
-All tests should pass except the test marked as KnownFailureTest. If some test 
-fails on your machine, you are encouraged to tell us what went wrong on the 
-``theano-users@googlegroups.com`` mailing list.
-
 Updating
 -------------
 

doc/library/config.txt

@@ -147,6 +147,30 @@ Config Attributes
 
     When the mode is Mode, it set the default optimizer used.
 
+.. attribute:: warn.ignore_bug_before
+
+    String value: 'None', 'all', '0.3'
+
+    Default: 'None'
+
+    When we fix a Theano bug that generated bad result in a case, we also make
+    Theano raise a warning when it enconter it again. This help to detect if fixed bug
+    affected your past experiments as you only need to run your experimentand not
+    understands the Theano internal that trigger the bug. A better way to detect
+    that see this will be implemented. See this
+    `ticket <http://trac-hg.assembla.com/theano/ticket/514>`__.
+
+    This flags allo new user to don't get warning about old fixed bug
+    that they don't need. You can set its value to the first version of Theano 
+    that you used(probably 0.3 or higher)
+
+    `None` mean that we should all warning.
+    `all` mean to hide all warning.
+
+    It is recommended that you put a version, so that you will see futur warning.
+    It is also recommended you put this into the .theanorc to have this always
+    actif.
+
 .. attribute:: home
 
     Default: env-variable $HOME

theano/configdefaults.py

@@ -107,23 +107,30 @@ AddConfigVar('experimental.mrg',
 ###
 ### To disable some warning about old bug that are fixed now.
 ###
-AddConfigVar('warn.old_bug_default',
-             "If False, will disable by default the warning about old Theano bug. If you never used Theano, you set it to False.",
-             BoolParam(True))
-default_warn = config.warn.old_bug_default
+AddConfigVar('warn.ignore_bug_before',
+             "If None, we warn about all Theano bug found by default. If all we don't warn about Theano bug found by default. If a version, we print warning only for Theano bug found after that version.",
+             EnumStr('None', 'all', '0.3', allow_override=False))
+
+default_0_3 = True
+if config.warn.ignore_bug_before=='None':
+    default_0_3 = True
+elif config.warn.ignore_bug_before=='All':
+    default_0_3 = False
+elif config.warn.ignore_bug_before>='0.3':
+    default_0_3 = False
 
 AddConfigVar('warn.argmax_pushdown_bug',
              "Warn if in past version of Theano we generated a bug with the optimisation theano.tensor.nnet.nnet.local_argmax_pushdown optimization. Was fixed 27 may 2010",
-             BoolParam(default_warn))
+             BoolParam(default_0_3))
 
 AddConfigVar('warn.gpusum_01_011_0111_bug',
              "Warn if we are in a case where old version of Theano had a silent bug with GpuSum pattern 01,011 and 0111 when the first dimensions was bigger then 4096. Was fixed 31 may 2010",
-             BoolParam(default_warn))
+             BoolParam(default_0_3))
 
 AddConfigVar('warn.sum_sum_bug',
              "Warn if we are in a case where Theano version between version 9923a40c7b7a and the 2 august 2010(fixed date), generated an error in that case. This happen when their is 2 consecutive sum in the graph, bad code was generated. Was fixed 2 August 2010",
-             BoolParam(default_warn))
+             BoolParam(default_0_3))
 
 AddConfigVar('warn.sum_div_dimshuffle_bug',
              "Warn if previous versions of Theano (between rev. 3bd9b789f5e8, 2010-06-16, and cfc6322e5ad4, 2010-08-03) would have given incorrect result. This bug was triggered by sum of division of dimshuffled tensors.",
-             BoolParam(default_warn))
+             BoolParam(default_0_3))