Free graphical calculator software for linux

A practical lambda-calculator is a normal-order evaluator for the untyped lambda-calculus, extended with convenient commands and shortcuts to make programming in it more productive.

Shortcuts are distinguished constants that represent terms. Commands define new shortcuts, activate tracing of all reductions, compare terms modulo alpha-conversion, print all defined shortcuts and evaluation flags, etc.

Terms to evaluate and commands are entered at a read-eval-print-loop (REPL) "prompt" or "included" from a file by a special command. A Haskell branch is an embedding of the lambda calculator (as a domain-specific language) into Haskell. The calculator can be used interactively within Hugs or GHCi.

The present calculator implements what seems to be an efficient and elegant algorithm of normal order reductions. The algorithm is "more functional" than the traditionally used approach.

The algorithm seems identical to that employed by yacc sans one critical difference. The calculator also takes a more "functional" approach to the hygiene of beta-substitutions, which is achieved by coloring of identifiers where absolutely necessary. This approach is "more functional" because it avoids a global counter or the threading of the paint bucket through the whole the process. The integration of the calculator with Haskell lets us store terms in variables and easily and intuitively combine them.

The traditional recipe for normal-order reductions includes an unpleasant phrase "cook until done". The phrase makes it necessary to keep track of reduction attempts, and implies an ugly iterative algorithm. Were proposing what seems to be an efficient and elegant technique that can be implemented through intuitive re-writing rules.

Our calculator, like yacc, possesses a stack and works by doing a sequence of shift and reduce steps. The only significant difference from yacc is that the lambda-calculator "reparses" the result after the successful reduce step. The source and the target languages of our "parser" (lambda-calculator) are the same; therefore, the parser can indeed apply itself.

The parsing stack can be made implicit. In that case, the algorithm can be used for normalization of typed lambda-terms in Twelf.

The following examples show that lambda-calculus becomes a domain-specific language embedded into Haskell:

> c0 = f ^ x ^ x -- Church numeral 0
> succ = c ^ f ^ x ^ f # (c # f # x) -- Successor

> c1 = eval $ succ # c0 -- pre-evaluate other numerals
> c2 = eval $ succ # c1
> c3 = eval $ succ # c2
> c4 = eval $ succ # c3

It is indeed convenient to store terms in Haskell variables and pre-evaluate (i.e., normalize) them. They are indeed terms. We can always ask the interpreter to show the term. For example, show c4 yields (f. (x. f (f (f (f x))))).

let mul = a ^ b ^ f ^ a # (b # f) -- multiplication
eval $ mul # c1 ---> (b. b), the identity function
eval $ mul # c0 ---> (b. (f. (x. x))), which is "const 0"

These are algebraic results: multiplying any number by zero always gives zero. We can see now how lambda-calculus can be useful for theorem proving, even over universally-quantified formulas.

The calculator implements Dr. Fairbairns suggestion to limit the depth of printed terms. This makes it possible to evaluate and print some divergent terms (so-called tail-divergent terms):

Lambda_calc> let y_comb = f^((p^p#p) # (c ^ f#(c#c))) in eval $ y_comb#c
c (c (c (c (c (c (c (c (c (c (...))))))))))

It is amazing how well lambda-calculus and Haskell play together.

Date Calculator is a date calculator application written in pyqt. You can add or subtract days to a date, or calculate the number of days between two dates.

You can also choose to run your calculations using only working days and/or calculate inclusive of the start/end dates. There is a comprehensive gui for setting holiday dates.

Holidays can be fixed annual dates, variable dates, such as "the 1st Monday in June" or "the closest Monday to 22 February". This utility could be useful for people who need to be able to calculate time critical deadlines, such as lawyers.

Date Calculator application is also available as a superkaramba theme. You can download both from the download link.

Poor mans Financial Calculator project is a small financial and basic mathematical operations calculator applet.
The calculator registers work like the mythical HP-12C financial calculator, even the "n" rounding behaviour. The yellow fields also serve as operands for the arithmetic operations; for such ops, the blue field will show the result.
BEGIN button: If enabled, means that the first payment is made at the beginning of the period (important only for financial operations that involve PMT register)
FPC button: if enabled, Fractionary part of the Period ("n") will also be calculated using Compound interest; if disabled, fractionary part will use simple (linear) interest, which gives slightly higher interest values.
Enhancements:
- This release translates the code and messages to English and changes the license to the LGPL.

Command Line calculator "CLC" is the calculator that can calculate direct at the Linux console.

Extract the CLCC file to /usr/bin you might need to login as root or equvalent account, to be able to access it whenever you need it.

Then just write CLCC 67+89 and the answer will be presented to you directly.

CLCC calculates from left to right with no exceptions. CLC also have some extra parameters that is sent to CLC using backslash parameters.

CLCC r2 10/3 this will round the result to 2 decimals you can use 1 to 9 if you want to round the sum of.

the r parameter can also be combined with the other parameters but it must be added first like this

CLCC r3c 10/3 - to get 10 diveded with 3 rounded down to 3 decimals.

CLCC is tested with Ubuntu 6.10 and Puppy OS 2.13 but should work with any Linux version in console mode.

The program is developed using Hotbasic for Linux and is Freeware, hope you find it useful, send and email if you have any questions.

Hotbasic is a basic language that compiles into assembler direct, no interpeter that slows down the code, just pure assembler.

So if you want assembler in Linux but doesnt want to code in nasm, HotBasic is the compiler for you.

Debt Payoff Calculator is a simple set of PHP (5) scripts that will allow users of a web site to enter their monthly income, monthly budget, and outstanding debts.
The system can then generate a debt payoff report predicting how long it will take to pay off the debts.
The algorithm is:
1. Get total monthly income.
2. Get total monthly expenses.
3. Amount available for debt service is income - expenses;
4. Compute the "kicker" as %20 of Available, reduce available by this amount.
5. Compute the ratio of each debt to total debts.
6. Multiply Available by each ratio to get the potential payment.
7. For the smallest debt, add the kicker.
8. Test if any debts would be paid off
8a. If a debt could be paid off, make the payment, adjust the last debt pointer.
8b. Add any excess funds to the other potentials, using ratio2 which excludes the debt to be paid off.
8b. Repeat 8.
9. Make the remaining payments for debts not paid off.
Repeat 5-9 until all debts paid off.
Print the table of payments.
Enhancements:
- This release has been tested with Internet Explorer and Mozilla as clients.

Resistor Color Code Calculator project calculates the value of a resistor (an electronic component).

The colors on the resistor are input into the program, and the result displays the resistance value of the resistor.

This is much easier than memorizing rhymes to remember colors.