# modelx v0.11.0 (21 Nov 2020)¶

This release introduces the following enhancements and changes.

## Enhancements¶

Stack trace summary for performance checks

In order to diagnose performance bottlenecks, it is useful to have a report which shows how much time each formula took during an execution. get_stacktrace() now has a summarize option, and when the option is set to True, get_stacktrace() returns a dict whose keys are the representation strings of the called Cells, and whose values are dicts containing the statistics of the Cells. The sample code below creates a Model with two Cells, and runs the Model activating stack trace:

import time
import pandas as pd
import modelx as mx

m = mx.new_model()

m.time = time

@mx.defcells
def foo(x):
time.sleep(0.1)     # Waits 0.1 second
return foo(x-1) + 1 if x > 0 else bar()

@mx.defcells
def bar():
time.sleep(0.2)     # Waits 0.2 second
return 0

mx.start_stacktrace(maxlen=None)

foo(5)

df = pd.DataFrame.from_dict(mx.get_stacktrace(summarize=True), orient="index")

mx.stop_stacktrace()


The sample code above creates a DataFrame as df that shows how many times foo and bar Cells were called, how much time they took to execute their formulas, and the times that the execution entered into or left each of the formulas for the first and last time.

Cells

calls

duration

first_entry_at

last_exit_at

Model1.Space1.foo(x)

6

0.6097867488861084

1605873067.2099519

1605873068.0203028

Model1.Space1.bar()

1

0.20056414604187012

1605873067.8197386

1605873068.0203028

Deleted objects are now replaced with null objects

When deleted objects are referenced either in or outside of models, they are now replaced with null objects:

import modelx as mx

m = mx.new_model()
A = m.new_space("A")
B = m.new_space("B")

B.C = A

del m.A


In the sample model above, the Space A is a null object:

>>> A
<UserSpace null object>

>>> B.C
<UserSpace null object>


Accessing attributes of the null objects raises DeletedObjectError.

## Backward Incompatible Changes¶

• Cells._is_derived() and Cells._is_defined() are now methods instead of properties.

• repr of Spaces and Cells now based on their dotted names, such as <Cells Model1.B[3].foo(x)>

## Bug Fixes¶

• Fixed errors raised when reading models containing Pandas objects that were written by an older version of Pandas.

• Fixed errors raised when reading models containing pathlib.Path which were written on a different platform.