What is Descriptive Analytics?

This approach proves to be particularly useful for modeling pointer values,since we don’t care about specific addresses Software development but just want to give a uniqueidentifier to a memory location. Assigning a constant to x allowsus to make a conclusion that x can only have one value. When control flow fromthe “then” and “else” branches joins, x can have either value. It can be used in business to analyze survey results, demand trends, market research, website traffic, and more. Data software like Tableau is designed to help you build advanced charts that adhere to industry-standard analytical benchmarks and visualization types.

Code Generation and Optimization

Generally, compilers and static analysis tools can assume undefinedbehavior does not happen. Wedescribe an analysis that finds uninitialized reads in a section below. When we move backward, we get our output by taking the union or intersection of all the inputs of all of the successors, and we get our intput by reasoning locally about our facts. The algorithm is executed until all facts converge, that is, until they don’t change anymore.

Types of Data Flow Analysis

Data Flow Analysis (DFA) is a technique used in compiler design to gather information about the flow of data in a program. It tracks how variables are defined, used, and propagated through the control flow of the program to optimize code and ensure correctness. In conclusion we can say that with the help of this analysis, optimization can be done. Descriptive analytics is a type of data analytics that uses raw, historical data to identify patterns, trends, and relationships. This process helps decision-makers understand what occurred in the past using historical data. Then, they can use the data findings to find opportunities and challenges looking forward.

Uninitialized variables and “bottom” values¶

The reaching definition analysis calculates for each program point the set of definitions that may potentially reach this program point. Modern idiomatic C++ uses smart pointers to express memory ownership, however inpre-C++11 code one can often find raw pointers that own heap memory blocks. A lattice element could also capture the source locations of the branches thatlead us to the corresponding program point. Diagnostics would use thisinformation to show a sample buggy code path to the user. There are also requirements that all usage sites of the candidate function mustsatisfy, for example, that function arguments do not alias, that users are nottaking the address of the function, and so on.

Further reading

• For example, we may want to know if there are any possible null-pointer exceptions in our program.
• Then, they can use the data findings to find opportunities and challenges looking forward.
• There are several implementations of IFDS-based dataflow analyses for popular programming languages, e.g. in the Soot12 and WALA13 frameworks for Java analysis.
• While entering the if branch we deduce that x.has_value() is implied by theflow condition.
• We could still handle this case by finding a maximal range in the code wherepi could be in the Compatible state, and only refactoring that part.

The definition of c in b2 can be removed, since c is not live immediately after the statement. To find the above inefficiency we can use the available expressions analysis tounderstand that m42 is evaluated twice. However, this flavor of deadcode is invisible to the compiler because the flag can be turned on at anymoment.

• Having access to so much data through the dashboards helped Bank Mandiri understand trends in both their customer’s expectations and the financial services industry.
• ”, predictive analytics can help answer the question, “What is likely to happen?” They’re similar because they are both used to pull insights from historical data and can be very useful in business.
• In the code below b1 should not be checked in both the outer and inner “if”statements.
• Whether you’re filling out a customer satisfaction survey, returning a purchase, or sharing a social media post, many of our interactions become data.
• Imagine that we would like to refactor output parameters to return values tomodernize old code.
• These sets can be represented efficiently as bit vectors, in which each bit represents set membership of one particular element.

Too much information and “top” values¶

For example, one group may have only collected customer’s email addresses while the other only collected phone numbers. Marrying data housed in older formats like spreadsheets with newer software may be time-consuming. Identifying trends in customer behavior and preference is a major benefit of descriptive analytics. For example, a restaurant could use descriptive analytics to analyze data surrounding what time customers came to eat or which dishes were the most popular. These insights could be used to change the menu or staff employees at certain times of the day.

A practical lattice that tracks sets of concrete values¶

Taint analysis is very well suited to this problem because the program rarelybranches on user IDs, and almost certainly does not perform any computation(like arithmetic). While entering the if branch we deduce that x.has_value() is implied by theflow condition. We could still handle this case by finding a maximal range in the code wherepi could be in the Compatible state, and only refactoring that part. To determine whether a statement reads or writes a field we can implementsymbolic evaluation of DeclRefExprs, LValueToRValue casts, pointerdereference operator and MemberExprs.

In the code below b1 should not be checked in both the outer and inner “if”statements. One solution is to always replace delete with a call to reset(), and thenperform another analysis that removes unnecessary reset() calls. In the following example, the raw pointer is used to access the heap objectafter the ownership has been transferred. Definitive initialization proves that variables are known to be initialized whenread. If we find a variable which is read when not initialized then we generatea warning.

• However, in the function below the parameter c is not an output parameterbecause its field name is not overwritten on every path through the function.
• The information gathered is often used by compilers when optimizing a program.
• It’s used to understand overall performance at an aggregate level as it relies on historical data that has been combined or summarized from multiple sources.
• Marrying data housed in older formats like spreadsheets with newer software may be time-consuming.

Basic principles

Let’s take a look at how we use data flow analysis to identify an outputparameter. The refactoring can be safely done when the data flow algorithmcomputes a normal state with all of the fields proven to be overwritten in theexit basic block SQL and Data Analyst/BI Analyst job of the function. Of course, in a program with loops, symbolic expressions for flow conditions cangrow unbounded. A practical static analysis system must control this growth tokeep the symbolic representations manageable and ensure that the data flowanalysis terminates.