computer science

IFPS

IFPS is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand IFPS rather than just read about it. In short: IFPS (Interactive Financial Planning System) was a financial modeling language created by professor Gerald R. Wagner and his students of the University of Texas at Austin in the late 1970s.

Key takeaways

IFPS belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IFPS to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IFPS from memory before moving on to harder problems.

Reference excerpt

IFPS (Interactive Financial Planning System) was a financial modeling language created by professor Gerald R. Wagner and his students of the University of Texas at Austin in the late 1970s. IFPS was marketed by Execucom, an Austin-based company started by Wagner. The company was acquired by Comshare in 1991. IFPS was available for a variety of platforms, including IBM mainframes (VM/CMS), DEC VAX, various flavors of Unix, DOS-based PCs and Macintosh Computers (named "Mindsight"- running on two floppies). There were a number of versions, from about 1985, including optimization and a data area for storing data separately from models. IFPS seems to have been an important inspiration for the Javelin financial modeling application. Some parts of the IFPS approach were later used by Lotus's Improv, specifically the separation of model logic and data. Difference to spreadsheet software (Lotus 1-2-3 and later Excel): Mainframe and PC/Mac versions of IFPS completely separated the logic model (connections between variables) and the data. Both were bound together by data placeholder (like "earnings in Year1" in the logic model - to easily run scenarios . (Spreadsheet) columns were represented by Name1, Name2, name3 etc. The model logic was written in lines with placeholder- oriented text ( "earnings=sales-costs" etc.). Comment lines on the model could be included anywhere with //. IFPS mainframe versions also allowed to simulate stochastic events by providing a range of probability distributions. The IFPS approach made it easy to communicate complex models even to laymen and managers. IFPS was eventually out-competed by spreadsheets. IFPS was an essential financial model-development tool for long range planning and strategic planning, popular business practices in the 1980s. As an "English-like" language, IFPS made it very simple to express relationships among financial concepts without having to worry about sequential logic, as the program would figure out dependencies among variables. This allowed for simple creation of both financial and managerial accounting statements. I was fortunate to work with IFPS for over ten years as an analyst at Champlin Petroleum aka. Union Pacific Resources. I also attended seminars and conferences put on by Gerald Wagner and his team at EXECUCOM. I believe it was the rise of risk management in the commodity industries over "assumption-based" techniques like long range planning, rather than spreadsheets per se, which contributed to IFPS loss in popularity. [Edit by David Benepe]

References

Worked examples

Example 1 — a first encounter with IFPS

Start with the simplest possible case. Write down what IFPS claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to IFPS before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about IFPS ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of IFPS

In research: IFPS appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses IFPS in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: IFPS is common in secondary-school and first-year university syllabi. It links to neighbouring topics Financial software, Programming language topic stubs, so understanding it makes those chapters shorter.
In everyday life: Look for IFPS outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study IFPS in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IFPS means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain IFPS out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IFPS in simple terms?

IFPS (Interactive Financial Planning System) was a financial modeling language created by professor Gerald R. Wagner and his students of the University of Texas at Austin in the late 1970s.

Why does IFPS matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study IFPS?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on IFPS.