put the default value of THEANO_BLAS_LDFLAGS into config.py and changed so that…

theano/config.py

@@ -22,7 +22,8 @@ HOME = os.getenv('HOME')
 THEANO_CMP_SLOPPY = os.getenv('THEANO_CMP_SLOPPY', 0)
 
 #flag for compiling with an optimized blas library. Used for gemm operation
-THEANO_BLAS_LDFLAGS = os.getenv('THEANO_BLAS_LDFLAGS')
+#if THEANO_BLAS_LDFLAGS exist but empty, we will use numpy.dot()
+THEANO_BLAS_LDFLAGS = os.getenv('THEANO_BLAS_LDFLAGS','-lblas')
 
 #for gpu
 CUDA_ROOT = os.getenv('CUDA_ROOT')

theano/tensor/blas.py

@@ -33,22 +33,18 @@ def ldflags(libs=True, flags=False):
     Default: ['blas'], but environment variable THEANO_BLAS_LDFLAGS overrides this.
     """
     rval = []
-    if config.THEANO_BLAS_LDFLAGS:
-        tokens = config.THEANO_BLAS_LDFLAGS.split()
-        for t in tokens:
-            try:
-                t0, t1, t2 = t[0:3]
-                assert t0 == '-'
-            except:
-                raise ValueError('invalid token in THEANO_BLAS_LDFLAGS', t)
-            if t1 == 'L':
-                raise ValueError('library dir not allowed in THEANO_BLAS_LDFLAGS', t)
-            elif libs and t1=='l': # example -lmkl
-                rval.append(t[2:])
-            elif flags and t1!='l': # example -openmp
-                rval.append(t)
-    elif libs:
-        rval = ['blas']
+    for t in config.THEANO_BLAS_LDFLAGS.split():
+        try:
+            t0, t1, t2 = t[0:3]
+            assert t0 == '-'
+        except:
+            raise ValueError('invalid token in THEANO_BLAS_LDFLAGS', t)
+        if t1 == 'L':
+            raise ValueError('library dir not allowed in THEANO_BLAS_LDFLAGS', t)
+        elif libs and t1=='l': # example -lmkl
+            rval.append(t[2:])
+        elif flags and t1!='l': # example -openmp
+            rval.append(t)
     #print "blas linking against", rval
     return rval
 
@@ -371,6 +367,8 @@ class Gemm(GemmRelated):
         """
 
     def c_code(self, node, name, (_z, _a, _x, _y, _b), (_zout, ), sub): #DEBUG
+        if len(self.c_libraries())<=0:
+            return super(Gemm, self).c_code(node, name, (_z, _a, _x, _y, _b), (_zout, ), sub)
         full_code = self.build_gemm_call() % dict(locals(), **sub)
         return full_code
 
@@ -656,6 +654,8 @@ class Dot22(GemmRelated):
                 double b = 0.0;
         """
     def c_code(self, node, name, (_x, _y), (_z, ), sub): #DEBUG
+        if len(self.c_libraries())<=0:
+            return super(Dot22, self).c_code(node, name, (_x, _y), (_z, ), sub)
         full_code = self.build_gemm_call() % dict(locals(), **sub)
         return full_code
     def c_code_cache_version(self):