## Issue

I am unable to plot graph-neural-networking. I have seen few related questions(1, 2, 3) to this topic but their answers do not apply to graph-neural-networks.

What makes it different is that the input vector include objects of different dimensions e.g. properties matrix dimension is `[n_nodes, n_node_features]`

, adjacency matrix dimension is `[n_nodes, n_nodes]`

etc. Here is the example of my Model:

```
class GIN0(Model):
def __init__(self, channels, n_layers):
super().__init__()
self.conv1 = GINConv(channels, epsilon=0, mlp_hidden=[channels, channels])
self.convs = []
for _ in range(1, n_layers):
self.convs.append(
GINConv(channels, epsilon=0, mlp_hidden=[channels, channels])
)
self.pool = GlobalAvgPool()
self.dense1 = Dense(channels, activation="relu")
self.dropout = Dropout(0.5)
self.dense2 = Dense(channels, activation="relu")
def call(self, inputs):
x, a, i = inputs
x = self.conv1([x, a])
for conv in self.convs:
x = conv([x, a])
x = self.pool([x, i])
x = self.dense1(x)
x = self.dropout(x)
return self.dense2(x)
```

One of the answers in 2 suggested to add `build_graph`

function as follows:

```
class my_model(Model):
def __init__(self, dim):
super(my_model, self).__init__()
self.Base = VGG16(input_shape=(dim), include_top = False, weights = 'imagenet')
self.GAP = L.GlobalAveragePooling2D()
self.BAT = L.BatchNormalization()
self.DROP = L.Dropout(rate=0.1)
self.DENS = L.Dense(256, activation='relu', name = 'dense_A')
self.OUT = L.Dense(1, activation='sigmoid')
def call(self, inputs):
x = self.Base(inputs)
g = self.GAP(x)
b = self.BAT(g)
d = self.DROP(b)
d = self.DENS(d)
return self.OUT(d)
# AFAIK: The most convenient method to print model.summary()
# similar to the sequential or functional API like.
def build_graph(self):
x = Input(shape=(dim))
return Model(inputs=[x], outputs=self.call(x))
dim = (124,124,3)
model = my_model((dim))
model.build((None, *dim))
model.build_graph().summary()
```

However, I am not sure how to define dim or Input Layer using `tf.keras.layers.Input`

for such a hybrid data-structure as described above.

Any suggestions?

## Solution

Here is the minimal code to plot such subclass multi-input model. Note, as stated in the comment above, there are some issue of your `GINConv`

which is from `spektral`

and it’s not related to the main query. So, I will give general soluton of such multi-input modeling scenarios. To make it work with your `speckral`

, please reach to the package author for further discussion.

From `specktral`

repo, here, I got the idea the shape of the input tensors.

```
x, y = next(iter(loader_tr))
bs_x = list(x[0].shape)
bs_y = list(x[1].shape)
bs_z = list(x[2].shape)
bs_x, bs_y, bs_z
([1067, 4], [1067, 1067], [1067])
```

Similar model, it also takes same amount of inputs and with same shape. But without `GINConv`

.

```
class GIN0(Model):
def __init__(self, channels, n_layers):
super().__init__()
self.conv1 = tf.keras.layers.Conv1D(channels, 3, activation='relu')
self.conv2 = tf.keras.layers.Conv1D(channels, 3, activation='relu')
self.dense1 = Dense(channels, activation="relu")
self.dropout = Dropout(0.5)
self.dense2 = Dense(n_out, activation="softmax")
def call(self, inputs):
x, a, i = inputs
x = self.conv1(x)
x = tf.keras.layers.GlobalAveragePooling1D()(x)
a = self.conv2(a)
a = tf.keras.layers.GlobalAveragePooling1D()(a)
x = tf.keras.layers.Concatenate(axis=1)([a, x, i])
x = self.dense1(x)
x = self.dropout(x)
return self.dense2(x)
def build_graph(self):
x = tf.keras.Input(shape=bs_x)
y = tf.keras.Input(shape=bs_y)
z = tf.keras.Input(shape=bs_z)
return tf.keras.Model(
inputs=[x, y, z],
outputs=self.call([x, y, z])
)
```

```
model = GIN0(channels, layers)
model.build(
[
(None, *bs_x),
(None, *bs_y),
(None, *bs_z)
]
)
# OK
model.build_graph().summary()
# OK
tf.keras.utils.plot_model(
model.build_graph(), show_shapes=True
)
```

Answered By – M.Innat

**This Answer collected from stackoverflow, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0 **