transfercolor via lab converter now implemented by tensorflow-cpu, which is x2 faster than skimage.

We cannot use GPU for lab converter in converter multiprocesses, because almost all VRAM ate by model process, so even 300Mb free VRAM not enough for tensorflow lab converter.
Removed skimage dependency.
Refactorings.

gpufmkmgr/gpufmkmgr.py

@@ -5,6 +5,8 @@ import contextlib
 from utils import std_utils
 from .pynvml import *
 
+
+        
 dlib_module = None
 def import_dlib(device_idx):
     global dlib_module
@@ -22,18 +24,26 @@ keras_module = None
 keras_contrib_module = None
 keras_vggface_module = None
 
+def set_prefer_GPUConfig(gpu_config):
+    global prefer_GPUConfig
+    prefer_GPUConfig = gpu_config
+    
 def get_tf_session():
     global tf_session
     return tf_session
-    
-#allow_growth=False for keras model
-#allow_growth=True for tf only model
-def import_tf( device_idxs_list, allow_growth ):
+
+def import_tf( gpu_config = None ):
+    global prefer_GPUConfig
     global tf_module
     global tf_session
     
+    if gpu_config is None:
+        gpu_config = prefer_GPUConfig
+    else:
+        prefer_GPUConfig = gpu_config
+        
     if tf_module is not None:
-        raise Exception ('Multiple import of tf is not allowed, reorganize your program.')
+        return tf_module
 
     if 'TF_SUPPRESS_STD' in os.environ.keys() and os.environ['TF_SUPPRESS_STD'] == '1':
         suppressor = std_utils.suppress_stdout_stderr().__enter__()
@@ -48,14 +58,18 @@ def import_tf( device_idxs_list, allow_growth ):
     import tensorflow as tf
     tf_module = tf
     
-    visible_device_list = ''
-    for idx in device_idxs_list: visible_device_list += str(idx) + ','
-    visible_device_list = visible_device_list[:-1]
+    if gpu_config.cpu_only:
+        config = tf_module.ConfigProto( device_count = {'GPU': 0} )
+    else:    
+        config = tf_module.ConfigProto()
+        visible_device_list = ''
+        for idx in gpu_config.gpu_idxs: visible_device_list += str(idx) + ','
+        visible_device_list = visible_device_list[:-1]
+        config.gpu_options.visible_device_list=visible_device_list
+        config.gpu_options.force_gpu_compatible = True
         
-    config = tf_module.ConfigProto()
-    config.gpu_options.allow_growth = allow_growth
-    config.gpu_options.visible_device_list=visible_device_list
-    config.gpu_options.force_gpu_compatible = True
+    config.gpu_options.allow_growth = gpu_config.allow_growth
+    
     tf_session = tf_module.Session(config=config)
         
     if suppressor is not None:  
@@ -71,11 +85,15 @@ def finalize_tf():
     tf_session = None
     tf_module = None
 
+def get_keras():
+    global keras_module
+    return keras_module
+    
 def import_keras():
     global keras_module
     
     if keras_module is not None:
-        raise Exception ('Multiple import of keras is not allowed, reorganize your program.')
+        return keras_module
         
     sess = get_tf_session()
     if sess is None:
@@ -241,4 +259,48 @@ def getDeviceName (idx):
     if idx < nvmlDeviceGetCount():    
         result = nvmlDeviceGetName(nvmlDeviceGetHandleByIndex(idx)).decode()
     nvmlShutdown()
-    return result
+    return result
+    
+    
+class GPUConfig():    
+    force_best_gpu_idx = -1
+    multi_gpu = False
+    force_gpu_idxs = None
+    choose_worst_gpu = False
+    gpu_idxs = []
+    gpu_total_vram_gb = 0
+    allow_growth = True
+    cpu_only = False
+    
+    def __init__ (self, force_best_gpu_idx = -1, 
+                        multi_gpu = False, 
+                        force_gpu_idxs = None, 
+                        choose_worst_gpu = False,
+                        allow_growth = True,
+                        cpu_only = False,
+                        **in_options):
+                        
+        if cpu_only:
+            self.cpu_only = cpu_only
+        else:
+            self.force_best_gpu_idx = force_best_gpu_idx
+            self.multi_gpu = multi_gpu
+            self.force_gpu_idxs = force_gpu_idxs
+            self.choose_worst_gpu = choose_worst_gpu        
+            self.allow_growth = allow_growth
+      
+            gpu_idx = force_best_gpu_idx if (force_best_gpu_idx >= 0 and isValidDeviceIdx(force_best_gpu_idx)) else getBestDeviceIdx() if not choose_worst_gpu else getWorstDeviceIdx()
+
+            if force_gpu_idxs is not None:
+                self.gpu_idxs = [ int(x) for x in force_gpu_idxs.split(',') ]
+            else:
+                if self.multi_gpu:
+                    self.gpu_idxs = getDeviceIdxsEqualModel( gpu_idx )
+                    if len(self.gpu_idxs) <= 1:
+                        self.multi_gpu = False
+                else:
+                    self.gpu_idxs = [gpu_idx]
+            
+            self.gpu_total_vram_gb = getDeviceVRAMTotalGb ( self.gpu_idxs[0] )
+        
+prefer_GPUConfig = GPUConfig()