Calctus (カルクタス) is a calculator application for Windows developed for engineers.

→ See releases.

• Syntax highlighting and auto-completion.
• Decimal, hexadecimal, and binary numbers can be mixed.
• SI prefixes, datetime formats, RGB color representation and several other formats are also available.
• The formula history can be modified, and the calculation results are immediately regenerated.
• Built-in constants and built-in functions. Constants and functions can also be user-defined.
• Numerical solution of equations by Newton's method.

User-defined constants can also be used.

See Built-In Functions for details.

Now Calctus has 151 built-in functions.

Variables can be assigned using the equal sign.

a = 2
b = 3
a * b // --> 6.

JavaScript-style multiple assignment is available.

[a,b,c]=[10,20,30]
a // --> 10
b // --> 20
c // --> 30

User functions can be defined using the def keyword.

def f(x) = x^2
f(3) // --> 9.

Rust-style lambda function is available.

f=(a,b)=>a*b
f(3,4) // --> 12.

If there is only one argument, the parentheses can be omitted

f=x=>x^2
f(3) // --> 9.

Use the solve function to solve equations numerically by Newton's method.

def f(x)=x^2-2
solve(f) // --> [-1.414213562, 1.414213562].
solve(x=>x^2-2) // This gives the same result.

By default, the Newton's method is performed based on automatically generated initial values. Therefore, it may produce inaccurate results if the solution is concentrated in a small area or exists far from the origin.

In such cases, the 2nd argument can be given an initial value.

solve(sin,314) // --> 314.159265359.

That initial value can also be given as an array.

solve(sin,[-314,314]) // --> [-314.159265359, 314.159265359].

By providing the 2nd and 3rd arguments at the same time, a range of initial values can be specified. In this case, 101 values between these ranges are used as initial values.

solve(sin,-5,5) // --> [-3.141592654, 0, 3.141592654].

⚠️ Note that the solution obtained using the solve function is an approximation and does not necessarily correspond to the analytical solution.

Verilog-style part selection is available for arrays and scalar values.

array=[1,2,3]
array[1]   // --> 2.
array[1]=5 // --> [1, 5, 3].

x=0x1234
x[11:4]      // --> 0x23.
x[11:4]=0xab
x            // --> 0x1ab4.

Negative indexes represents distance from the end of the array. 🆕

array=[1,2,3,4,5]
array[-2]    // --> 4.
array[-3:-1] // --> [3, 4, 5].

Rust-style range operators can be used to generate sequences of numbers.

1..5  // --> [1, 2, 3, 4]
1..=5 // --> [1, 2, 3, 4, 5]

Python-style range functions can also be used.

range(1,5)              // --> [1, 2, 3, 4]
range(1,5,0.5)          // --> [1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5]
rangeInclusive(1,5)     // --> [1, 2, 3, 4, 5]
rangeInclusive(1,5,0.5) // --> [1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5]

Many unary and binary operators can be applied to arrays to perform operations on its individual elements.

-[1,2,3]        // --> [-1, -2, -3]
[1,2,3]*4       // --> [4, 8, 12]
[1,2,3]+[4,5,6] // --> [5, 7, 9]

Also functions with arguments marked with an asterisk can be vectorized by supplying an array for the argument.

For example, the power function pow(*x, y) can take an array as its x argument. pow([1,2,3],3) is equivalent to [pow(1,3),pow(2,3),pow(3,3)].

pow(2,3)        // --> 8
pow([1,2,3],3)  // --> [1, 8, 27]
prime(0..5)     // --> [2, 3, 5, 7, 11]

The opening parenthesis at the beginning of a line can be omitted.

1+2)*3 // --> 9

Exponent-part of E-notation and SI prefix can be adjusted using Alt + arrow keys.

If only an operator is entered, the expression is "popped" from the history and combined with that operator.

If you use RPN operation, it is recommended to turn off the automatic input of "ans" in the settings.

1 [Return]
2 [Return]
+ [Return] // --> "1" and "2" replaced with "1+2"
3 [Return]
4 [Return]
+* [Return] // --> "1+2", "3" and "4" replaced with "(1+2)*(3+4)"

Calctus can call scripts such as Python as functions.

Function arguments are passed to the script as command line arguments, and the standard output of the script is returned to Calctus.

1. Open the Scripts tab in the Calctus Settings dialog.
2. Check Enable External Script Functions.
3. If you want to specify the folder where you want to place the scripts, click the Change button to specify the folder.
4. Click the Open button. If asked if you want to create the folder, click Yes.
5. Place a python script add.py like the following in the folder.

   import sys
   a = float(sys.argv[1])
   b = float(sys.argv[2])
   print(a + b)

6. After closing the settings dialog, the add function is now available.

If you wish to use a scripting language other than Python, please register the extension and interpreter in the Scripts tab of the Settings dialog.

plot(func) can be used to draw a graph. func is a function that takes one argument. The value of the argument is plotted on the horizontal axis and the return value of the function on the vertical axis.

⚠️ This feature is experimental and may be removed in future versions.