# A simple code to calculate the performance metrics of a binary classifier

### 1. Code

import numpy as np

def perf_metrics_2X2(yobs, yhat):
"""
Returns the specificity, sensitivity, positive predictive value, and negeative predictive value
of a 2X2 table.

where:
0 = negative case
1 = positive case

Parameters
----------
yobs : array of . . .

February 08, 2018

# How to create an alias in Windows Powershell to launch Jupyter and Python

### - Why am I doing this?

Running Jupyter and PIP becomes painful if you don't have admin privileges for your computer; A solution to this is to enter the entire path to PIP and/or Jupyter but it can very time consuming and inefficient. A way around this is to create and alias for the terminal to interpret a short command as if you . . .

December 01, 2017

# Tuning scikit-learn parameters using optimization instead of random search

## The problem

On previous posts I described how to perform non-linear curve fitting in Ptyhon and Julia. At their core non-linear and linear curve fitting (or regression) are optimization problems in which we find the parameters that minimize an objective function. The entire field of mathematical optimization is concerned . . .

November 13, 2017

No content...

# Why am I doing this?

This is the second installment on a blog series about how to use Python for Data Analysis at CyVerse. If you are not familiar with CyVerse, please read my previous post.

## What you will need

1. An Instance (Virtual Machine) in Atmosphere. Read the previous blog on this series if you don't . . .

July 20, 2017

# Why am I doing this?

The current workflow for data analysis and scientific computing in medical imaging requires the storage and processing of tens of millions of voxels per patient. Unfortunately, a personal PC/laptop is inadequate for such tasks.

## What is CyVerse?

"OUR MISSION TO DESIGN, DEPLOY, . . .

July 20, 2017

# Non Linear regression in Julia is ~10X faster than Python and ~635X faster than Matlab.

## Why Julia ?

I gave a talk a couple weeks ago at the Tucson Python MeetUp about how Julia and Python can
be used to analyze medical images. It turns out that for a simple processing task of calculating a T1 map of a lemon Julia is ~10X faster than Python and ~635X faster than Matlab. Besides speed, Julia offers great features:

. . .